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Document DEVICE REPORTBock-service-manual-commercial-electric-heater
http://waterheatertimer.org/3-phase-water-heater.html
Energy Saver
Commercial Electric Energy Saver Water Heater
IMMERSION AND SURFACE MOUNTED THERMOSTAT MODELS
SERVICE MANUAL
Troubleshooting Guide and Instructions for Service
(To be performed ONLY by qualified service providers)
For Models 50(A)*(SF, CF)-** 80(A)*(SF, CF)-** 120(A)*(SF, CF)-** *Denotes kW Rating **Denotes Wiring Code
Manual 238-47174-00B - Save this manual for future reference

Commercial Electric

Water Heaters

Table of Contents

Introduction/Tools General Information Sequence of Operation Troubleshooting Heating Element Testing Line Voltage Testing Fuse Testing High Limit (ECO) Testing (Surface Mounted) High Limit (ECO) Testing (Surface Mounted @ 600V) High Limit (ECO) Testing (Contactor Models) Thermostat Operation Testing (Surface Mounted) Thermostat Operation Testing (Surface Mounted @ 600V) Thermostat Operation Testing (Contactor Models) Contactor Operation Testing Thermostat Removal & Replacement (Surface Mounted) Thermostat Removal & Replacement (Contactor Models) ECO Removal & Replacement (Contactor Models) ECO Removal & Replacement (Surface Mounted @ 600V) Heating Element Removal & Replacement Anode Inspection & Replacement Generic Parts List Glossary of Terms

Page 2 3 10 13 15 16 17 18 19 20 21 22 23 24 26 27 28 29 30 31 32 33

Service Procedure - - - - - - - - I II III IV V VI VII VIII IX X XI XII XIII XIV XV XVI - - - - -

Introduction
This service manual is designed to aid service and maintenance professionals in the function, proper
diagnosis and repair of Bock Water Heaters Commercial Electric Water Heaters.

The text and illustrations in this manual provide step-by-step instructions to facilitate proper operation and troubleshooting procedures. Contact Bock Water Heaters Technical Support immediately if diagnosis cannot be made using the methods described in this service manual.

Tools
- Multi-Meter - 1-1/2" Deep Well Socket - 1-1/16" Deep Well Socket - 1/4" Nut Driver

- Philips Head Screw Driver - Common Screw Driver - Thermometer - Drain Hose.

Other hand tools: pipe wrench, channel locks, pliers (common & needle nose), wire cutters, wire strippers, allen wrench set, flash light.

2

Commercial Electric
General Information
Bock Waters Heaters Commercial Electric water heaters can be manufacturered with a choice between two different types of thermostat control options as follows:
Surface Mounted Thermostats. Immersion Thermostat (contactor models).
The model number is coded to identify the specific thermostat control system used for a particular unit. Below is a typical model number and coded definitions.
50 SF 6 208/240
Volts
kW Rating
CF - Contactor w/Fuse (Immersion Thermostat) SF - Surface Thermostat w/Fuse
Tank Capacity

Model Number Electrical Characteristics

MFG FOR: BOCK WATER HEATERS, INC. 110 S. DICKINSON, MADISON WI 53703 Model No: 50SF-6, 208/240 Serial No: ZB2564812 Cap. 50(gal.)/189.3(liters) Press: Test 300(psi), Working 150(psi)

Volts 240

Max Temp 180°

Phase Three Amps 29

kW Each 4

Total kW 12 3 Elements

Wattage rating based upon 60 Hz

Typical Rating Plate Located on Front of Water Heater

3

GENERAL INFORMATION

Contactor Models General Controls Layout

Upper Control Box
Thermostat Direct Immersion Bulb
Lower Control Box

Ground Lug Terminal Block
Fuse Block (s)
Contactor (s) High Limit (ECO) Direct Immersion Bulb High Limit (ECO) Control Immersion Thermostat Control
Heating Elements

Surface Mounted Thermostat Models General Controls Layout

Upper Control Box

Ground Lug Terminal Block Fuse Block (s)

Lower Control Box

Surface Mounted Thermostats with ECO
Heating Elements

4

GENERAL INFORMATION

600V Surface Thermostat (w/Contactors) Models General Controls Layout

Upper Control Box

Ground Lug Terminal Block

High Limit (ECO) Control

Contactor(s) Surface Thermostats

Lower Control Box

Heating Elements

5

GENERAL INFORMATION
Surface Mounted Thermostats
Surface mounted thermostats are mounted into a bracket above each heating element. The bracket holds the thermostat against the side of the tank responding to tank surface temperatures to sense a call for heat, set point temperature and high limit (ECO) activation. As each element has a dedicated thermostat (for all models excluding 600V), it is possible to sequence the elements by varying the settings on the thermostats.

Manual ECO (High Limit) Reset Button
Temperature Control Dial

Surface Mount Combination Thermostat/
ECO (high limit) 89T Series

Immersion Style Thermostat Control for Contactor Models
The thermostat will complete control circuit voltage upon a call for heat. Likewise, the control will interrupt control circuit voltage when the water temperature is sufficient to satisfy the adjustable temperature limit of control.

Direct Immersion
Bulb

Immersion Style High Limit (ECO) Control for Contactor Models
The high limit (ECO) control will interrupt control circuit voltage causing the heater to shut down when the high temperature limit of the control is reached (196° F ± 4° F). Once the cause for overheated water has been determined, the control must be manually reset to restore normal operation.

Manual Reset Button

Direct Immersion Bulb

6

GENERAL INFORMATION

Surface Mounted Thermostats (w/Contactors) for 600V Models
600V models use contactors to deliver line voltage to the heating elements. However, rather than the immersion type high limit and thermostat devices, surface mounted thermostats are used to operate the control circuit of the water heater.

Surface Mounted Thermostat 59T Series

Surface Mounted ECO (High Limit)

Temperature Control Dial

Manual Reset Button

7

GENERAL INFORMATION
Contactor
Contactor operation is achieved by energizing an operating coil in response to a call for heat from the immersion thermostat. Upon a call for heat, one or more contactors will energize all heating elements simultaneously. The operating coils are voltage specific. When contactor replacement is required be sure to order the proper operating coil based on the voltage rating found on the rating plate located on the front of the water heater.

Terminal Connections to the Fuse Block and/or Terminal Block
Terminal Connections to the Heating Elements

Terminal Connections of Contactor Operating Coil

Direct Immersion "Screw-in" Type Heating Element

1- ½" Hex Screw-in Flange

Terminal Block

Zinc-plated Copper or Incoloy Sheath

0642 4500W 240V RC02404524

Terminal Block Screw Element Rating Ink Stamped on Side of Terminal Block

8

GENERAL INFORMATION

Commonly Used Formulas

(Single Phase)

Amps

=

Watts Volts

(Balanced 3 Phase)

Amps =

Watts Volts x 1,732

Watts = Amps x Volts

Common Service Wire Configurations

240V 1Ph

BLACK Ungrounded

GREEN Grounding

RED Ungrounded

Ohms

=

Volts2 Watts

240

120

120

208 3Ph

Neutral A

B

C

120

120

120

208

208

208

RED BLACK RED

240 3Ph

Neutral A

B

C

120

120

120

240

240

240

RED BLACK RED

480 3Ph/277 1Ph

Neutral A

B

C

277

277

277

480

480

480

RED BLACK RED

Commonly Used Formulas

208 Volt

240 Volt

277 Volt 380 Volt 415 Volt

480 Volt

600 Volt

kW 1 Phase 3 Phase 1 Phase 3 Phase 1 Phase 3 Phase 3 Phase 1 Phase 3 Phase 3 Phase

6

28.8

16.6

25.0

14.4

21.6

9.1

8.3

12.5

7.2

5.8

9

43.2

25.0

37.2

21.6

32.4

13.6

12.5

18.7

10.8

8.7

12

57.6

33.3

50.0

28.9

43.3

18.2

16.7

25.0

14.4

11.5

13.5 64.9

37.5

56.2

32.5

48.7

20.5

18.8

28.1

16.2

13.0

15

72.1

41.6

62.5

36.1

54.1

22.7

20.9

31.2

18.0

14.4

18

86.5

50.0

75.0

43.4

64.0

27.3

25.0

37.5

21.6

17.3

24 115.4

66.7

100.0

57.8

86.6

36.4

33.4

50.0

28.9

23.1

27 129.8

75.0

112.5

65.0

97.4

41.0

37.5

56.2

32.5

26.0

30 144.2

83.3

125.0

72.2

108.3

45.6

41.7

62.5

36.1

28.9

36 173.0 100.0 150.0

86.7

129.9

54.7

50.1

75.0

43.3

34.6

45

216.3 125.0 187.5 108.3 162.4

68.4

62.6

93.7

54.1

43.3

54

259.6 150.0 225.0 130.0 194.9

82.0

75.1

112.5

65.0

52.0

9

SEQUENCE OF OPERATION

Bock's commercial electric water heaters can use either immersion thermostats (contactor models) or surface mounted thermostats. Sequence of operation for each configuration is explained below. It would be impractical to show all wire diagrams applicable to both configurations. A "typical wiring diagram" is illustrated to aid in understanding the principles of the operating sequence.

Immersion Thermostats (Contactor Models): Configured to use a single immersion thermostat to control one or more contactors to energize or de-energize all elements simultaneously. In addition, a separate high limit (ECO) control with manual reset is wired in series with the thermostat. Both controls use a direct immersion bulb inserted into the tank to sense water temperature. Immersion thermostat and high limit control are mounted to provide temperature adjustment and manual reset access from the exterior of the unit.

Surface Mounted Thermostats: Surface mounted thermostats are mounted inside the lower control box, in a bracket above

each heating element. The bracket holds the thermostat against the side of the tank, responding to tank surface temperatures

to sense a call for heat, set-point temperature and high limit (ECO) activation. As each element is controlled by a dedicated

thermostat, it is possible to sequence the elements by varying the settings on the thermostat. However, 600V models with

surface mounted thermostats operate contactors in the

Line Voltage

same manner as an immersion thermostat model, only using

surface thermostats to sense the call for heat.

Sequence of operation for each system is explained below.

OR

Fuse Block

Sequence of Operation: Immersion Thermostat (Contactor Models).

Terminal Block

The system has two distinct circuits: 1. Power Circuit (solid line). 2. Control Circuit (dotted line).

Contactor Coil

1. Line voltage is applied across terminals of fuse block or a terminal block. Line voltage continues down and connects to terminals L1, L2 and L3 of one or more contactors.

Contactor

ECO (High Limit)

A. Contactor is open (no call for heat), so there is no

voltage across terminals T1, T2 and T3 of contactor.

T'stat

B. The contactor is controlled by the control circuit consisting of the immersion thermostat, ECO (high limit) and contactor coil.

2. When the thermostat calls for heat, contacts close inside the thermostat completing the circuit through the ECO and energizing the contactor coil.

3. The energized contactor coil causes the contactor to close energizing the elements from terminals T1, T2 and T3 of the contactor.

4. When the temperature setting of the thermostat is reached, the contacts in the thermostat open. This interrupts current flow through the control circuit de-energizing the contactor coil.

5. The de-energized contactor coil causes the contactor to open, interrupting current flow through the elements. The heater is now in stand-by, waiting for the next call for heat.

Heating Elements

10

Sequence of Operation: Surface Mounted Thermostats.
1. Line voltage is applied across terminals of fuse block or a terminal block. Line voltage continues down and connects to surface mounted thermostats at terminals L1 and L3.

SEQUENCE OF OPERATION

Line Voltage
1
Fuse Block

Terminal Bloc

2. ECO (high limit) in thermostat is closed, so there is line voltage

2

present at terminal L4 of

thermostats and to one side of each element.

ECO Closed

Power to one side of element

3. Water in the tank is cold, so all thermostats are closed at

Thermostat closed

3

terminal T2 (calling for heat). This

at terminal T2

completes the circuit and allows

current to flow through heating

elements.

4. As each thermostat is satisfied, it opens at terminal T2, interrupting

4

current flow through the

respective element. The system is now in stand-by mode waiting for the next call for heat.

Thermostat open at terminal T2

Surface Mounted Thermostat
Heating Element

11

SEQUENCE OF OPERATION

Sequence of Operation: 600V Surface Mounted Thermostats (w/Contactors).
The system has two distinct circuits. 1. Power Circuit - Line Voltage (600V) 2. Control Circuit - 120V
1. Line voltage is applied across terminals of fuse block or a terminal block. Line voltage continues down and connects to terminals L1, L2 and L3 of one or more contactors.
A) Contactor is open (no call for heat), so there is no voltage across terminals T1, T2, and T3 of contactor.
B) The contactor is controlled by the control circuit consisting of the surface mounted thermostat, ECO (high limit) and contactor coil.
2. When the thermostat calls for heat, contacts close inside the thermostat completing the circuit through the ECO and energizing the contactor coil.
3. The energized contactor coil causes the contactor to close, energizing the elements from terminals T1, T2 and T3 of the contactor.
4. When the temperature setting of the thermostat is reached, the contacts in the thermostat open. This interrupts current flow through the control circuit de-energizing the contactor coil.
5. The de-energized contactor coil causes the contactor to open, interrupting current flow through the elements. The heater is now in stand-by waiting for the next call for heat.
6. Notice in the wiring diagram at right that each row of elements is equipped with a surface mounted thermostat on the highest element in the row. These thermostats are individually wired in series to the contactor whose line voltage corresponds to the same row of elements. Each thermostat and contactor combination are wired to the ECO in parallel. This allows for each row of elements to be powered "ON" independent of the other element rows. However, the ECO is wired in series so that voltage can be interrupted to the entire control circuit if the ECO senses that the tank water has become overheated.

6 Element Configuration Shown (9 Elements Possible)

Transformer 60VA

Fuse Block

Line Voltage

Contactor

High Limit 59T 59T

Heating Elements

12

TROUBLESHOOTING
The most common cause of improper electric water heater operation can be linked to heating element failure.
When troubleshooting an electric water heater with the incidence of "no hot water" or "insufficient amount of hot water" it is always a good idea to check the heating elements first following the procedure on Page 15.
Common heating element failures are:
1. Dry Firing. Elements may be partially submerged in water or most likely, completely exposed with no water in the tank at all. In open air, an energized element (dry-fired) will become completely inoperable within seconds. In some cases sediment or lime build up around an element can eventually cause an air pocket, resulting in a dry-fired element. When element replacement is required, be sure tank is full of water prior to energizing the water heater.
2. Grounded Element. In most cases, an element with a short circuit to ground will cause the circuit breaker in the service panel to open or shut off. In some cases there may not be enough current draw for the circuit breaker to open. This will allow the heating element to be in continuous operation resulting in overheated water, limited only by the ECO located in the thermostat circuit. Repeated actuation of the ECO usually is the result of a grounded heating element.
3. Sediment Buildup. Slow hot water recovery can usually be traced back to sediment or lime build-up around heating element. Sediment build-up can also, over time, cause a dry-fired element.
If a heating element is found to be inoperative, it must be replaced. Follow service procedure MCE-XV on Page 30.
The illustration below shows a common "screw-in" type heating element identifying certain features commonly referred to throughout this manual.

Typical Direct Immersion "Screw-In" Type Heating Element

1- ½" Hex Screw-in Flange

Terminal Block

Zinc-plated Copper or Incoloy Sheath

0642 4500W 240V RC02404524

Terminal Block Screw Element Rating Ink Stamped on Side of Terminal Block

13

TROUBLESHOOTING

Quick Step Plan to Hot Water
1. STOP, DANGER! Turn power "OFF" to water heater.
2. Check all wire connections to insure that they are snug and corrosion free.

WARNING High voltage exposure. Use caution when making voltage checks to avoid hazard to
life or property.

3. Reset high limit (ECO) (Page 18-20).

4. Check for inoperative heating element (Page 15).

5. Check line voltage (Page 16), and internal fuses (Page 17).

6. Refer to table below if items 1 through 5 above do not correct problem.

SYMPTOM

PROBABLE CAUSE

No Hot Water
Not Enough Hot Water or
Continues Operation
Slow Hot Water Recovery
Overheated Water
Noisy (singing or hissing) Elements Noisy Contactor

1. No power to heater. 2. Blown water heater fuses. 3. Loose wire connections. 4. Inoperative heating elements. 5. Inoperative thermostat(s) 6. Open ECO. 7. Inoperative contactor(s).
1. Inoperative heating element. 2. Sediment or lime buildup on element(s). 3. Thermostat(s) set too low. 4. Inoperative thermostat(s). 5. Inoperative contactor(s). 6. Loose wire connection. 7. High demand period. 8. Undersized heater. 9. Very cold inlet water to heater. 10. Plumbing connections reversed.
1. Sediment or lime buildup on element(s). 2. Loose wire connections. 3. Inoperative thermostat(s). 4. Inoperative contactor(s). 5. Derated heating element installed.
1. Surface thermostat(s) not flush with tank. 2. Grounded heating element(s). 3. Thermostat set too high. 4. Inoperative thermostat(s). 5. Inoperative ECO.
1. Lime formation on element(s). 2. High or low line voltage.
1. Low line voltage. 2. Debris between contactor plates. 3. Incorrect or defective operating coil. 4. Loose wire connections.

CORRECTIVE ACTION
1. Check circuit breakers at service panel. 2. Check water heater fuses. 3. Check all wire connections. 4. Check heating element(s). 5. Check thermostat(s) operation. 6. Reset (check) ECO. 7. Check contactor operation.
1. Check heating element(s). 2. Clean or replace heating element(s). 3. Increase thermostat setting. 4. Check thermostat(s). 5. Check contactor operation. 6. Check all wire connection. 7. Reduce demand. 8. Replace with larger heater. 9. Temper water to heater. 10. Correct plumbing connections.
1. Clean or replace heating elements. 2. Check all wire connections. 3. Check thermostat(s). 4. Check contactor operation. 5. Verify element voltage and wattage rating.
1. Check surface thermostat(s) mounting. 2. Check heating element(s). 3. Adjust thermostat(s) to desired setting. 4. Check thermostat(s). 5. Check ECO.

SERVICE PROCEDURE
2. III, Page 17 4. I, Page 15 5. VII-IX, Page 21-23 6. IV, VI, Page 18-20 7. X, Page 24-25
1. I, Page 15 2. XV, Page 30 4.VII-IX, Page 21-23 5. X, Page 24-25
1. XV, Page 30 3. VII-IX, Page 21-23 4. X, Page 24-25 5. See Page 8
1. XI, Page 26 2. I Page 15 4. VII-IX, Page 21-23 5. IV-VI, Page 18-20

1. Clean or replace heating element(s). 2. Verify line voltage to heater.

1. XV, Page 30 2. II, Page 16

1. Verify line voltage to heater. 2. Replace contactor. 3. Replace contactor. 4. Check wire connections.

1. II, Page 16

14

Test for Open or Burned Out Element.

1. STOP, DANGER! Turn power "OFF" to water heater.

2. Remove access cover from lower control box. Remove insulation from inside of control box.

3. Disconnect wires from heating element.

4. Set multi-meter to "ohms" setting.

5. Touch probes of multi-meter to screw terminals of heating element (see illustration 1).

6. Reading should be 12.8 ohms (± 6%) for a 240 volt, 4500 watt element, see table below for other elements.

Ohms = Volts2 Watts

A reading outside the range using the formula above (± 6%) indicates a bad element and the element must be replaced.

Ohms of Electrical Resistance for Commonly Used Elements

Element Wattage
2000 3000 4000 4500 5000 6000

Voltage Rating of Element

208

240

480

21.6

28.8

115.2

14.4

19.2

76.8

10.8

14.4

57.6

9.6

12.8

51.2

8.7

11.5

46.1

7.2

9.6

38.4

Test for Grounded Heating Element (Damaged Heating Element with Short Circuit to Ground).

1. STOP, DANGER! Turn power "OFF" to water heater.
2. Remove access cover from lower control box. Remove insulation from inside of control box.
3. Disconnect wires from heating element.
4. Set multi-meter to "ohms" setting.
5. Touch one probe of multi-meter to either screw terminal of heating element and the other on the element flange (see illustration 2). There should be no reading on the ohm meter. Any reading indicates a grounded element and the element must be replaced. Repeat this step for the other screw terminal.

SERVICE PROCEDURE I Heating Element Testing
WARNING High voltage exposure. To avoid hazard to life or property, be sure power is turned OFF to water heater while performing this
procedure.
NOTE Disconnect
Element Wires
Element Screw Terminals
Illustration 1

NOTE Disconnect
Element Wires
Element Flange

Illustration 2

Element Screw Terminal

15

SERVICE PROCEDURE II Line Voltage Testing

Line Voltage Testing.
Line voltage (single phase or three phase) will connect to a terminal block or directly to a fuse block located inside the control panel. Determine heaters voltage and phase by referring to the rating plate located on the front of the water heater. Apply the appropriate phase procedure below to determine if proper line voltage is present.
Single Phase Line Voltage Testing.
1. STOP, DANGER! Turn power "OFF" to water heater.
2. Open upper control panel door.
3. Determine connection point for line voltage from service panel, terminal block or fuse block.
4. Set multi-meter to volts AC. Be sure to scale meter for appropriate voltage.
5. Use caution and turn power "ON" to water heater.
6. Use caution and check voltage across top terminals where service voltage connects to water heater (see illustration 3).
A) Rated voltage IS present, power to the water heater is okay.
B) Rated voltage NOT present, check service panel.
Three Phase Line Voltage Testing.
1. STOP, DANGER! Turn power "OFF" to water heater.
2. Open upper control panel door.
3. Determine connection point for line voltage from service panel, terminal block or fuse block.
4. Set multi-meter to volts AC. Be sure to scale meter for appropriate voltage.
5. Use caution and turn power "ON" to water heater.
6. Use caution and check voltage across top terminals where service voltage connects to water heater (see illustration 4).
A) Rated voltage IS present, power to the water heater is okay.
B) Rated voltage NOT present, check service panel.

WARNING High voltage exposure. To avoid hazard to life or property, use extreme caution when
making voltage checks.

Line voltage from service panel
connected to Terminal block of heater

OR

Line voltage from service panel
connected to Fuse block of heater

Check voltage across top terminals.
Illustration 3

Line voltage from

Line voltage from

service panel connected to Terminal block

OR

service panel connected to Fuse block

of heater

of heater

Check voltage across top terminals.
Illustration 4

16

Fuse Testing. 1. STOP, DANGER! Turn power "OFF" to water heater. 2. Open upper control box to allow access to fuse block. 3. Locate fuse block and remove fuses. 4. Set multi-meter to the ohms setting. 5. Check continuity across fuse (see illustration 5).
A) Continuity IS present, fuse is okay. B) Continuity NOT present, replace fuse.

SERVICE PROCEDURE III Fuse Testing
WARNING High voltage exposure. To avoid hazard to life or property, be sure power is turned OFF to water heater while performing this
procedure.
Illustration 5

17

SERVICE PROCEDURE IV High Limit (ECO) Testing

High Limit Control (ECO) Testing for Surface Thermostat Models (NOT including 600V)
1. This procedure assumes line voltage and fuses are in working order.

WARNING High voltage exposure. To avoid hazard to life or property, use extreme caution when
making voltage checks.

2. This procedure illustrates testing of just one surface thermostat. Repeat this procedure for all surface thermostats on the water heater.
3. Turn power "OFF" to water heater.

ECO reset button

4. Remove lower control box cover and remove insulation from inside of control box.

5. Remove plastic cover from thermostat(s).

6. Turn power "ON" to water heater.

7. Use caution and check voltage across terminals L1 and L4 for all thermostats (see illustration 6).

A) Rated voltage IS present, ECO is okay. B) Rated voltage NOT present, proceed to step 8.

ELEMENT
Illustration 6

8. Turn power "OFF" to water heater and firmly press ECO reset button on thermostat(s). Turn power "ON" to water heater and recheck voltage across terminals L1 and L4 of thermostat(s).

A) Rated voltage IS present, the ECO has previously opened indicating the water in the tank, at some point, did overheat. Check the following:

1. Thermostat must be in full contact with tank. 2. Be sure heating element(s) is not shorted to ground (see Page 15). 3. Proper thermostat operation (see Page 21).

B) Rated voltage NOT present, water in tank may be overheated.

1. If water is overheated, turn "OFF" power to water heater and flow water through tank to cool below set point of upper thermostat. Reset ECO and recheck voltage.
2. If water is cool, replace thermostat(s).

18

SERVICE PROCEDURE V High Limit (ECO) Testing

High Limit Control (ECO) Testing for 600V Surface Thermostat Models.
1. This procedure assumes line voltage, transformer, fuses and thermostat are in working order.

WARNING High voltage exposure. To avoid hazard to life or property, use extreme caution when
making voltage checks.

2. Turn power "OFF" to water heater. 3. Remove lower control box cover and remove insulation from inside of control box.

ECO reset button

4. Use caution and check continuity across terminals 1 and 2 (see illustration 7).

A) Continuity IS present, ECO is okay.

B) Continuity NOT present, proceed to step 5.

5. Turn power "OFF" to water heater and firmly press ECO reset button on thermostat(s). Turn power "ON" to water heater and recheck continuity across terminals 1 and 2 of thermostat(s).

A) Continuity IS present, the ECO has previously opened indicating the water in the tank, at some point, did overheat. Check the following:

Illustration 7

1. Thermostat must be in full contact with tank. 2. Be sure heating element(s) is not shorted to ground (see Page 15). 3. Proper thermostat operation (see Page 22).

B) Continuity NOT present, water in tank may be overheated.

1. If water is overheated, turn "OFF" power to water heater and flow water through tank to cool below set point of upper thermostat. Reset ECO and recheck continuity.
2. If water is cool, replace ECO.

19

SERVICE PROCEDURE VI High Limit (ECO) Testing

High Limit Control (ECO) Testing for Contactor Models
Switch Contacts: Normally closed. Open on rise @ 196°F ± 4°F. Manual Reset.
1. Determine of high limit (ECO) has actuated. This can be done by simply depressing the reset buttons. If you hear and/or feel a small click, the switch has actuated.
2. Use caution and turn power on to water heater and observe heating cycle following the high limit heating cycle flow chart.
High Limit Control Continuity Testing for Contactor Models
1. STOP, DANGER! Turn power "OFF" to water heater.
2. Water temperature must be below 196°F ± 4°F.
3. Remove high limit switch from control panel. It is not necessary to remove immersion bulb from tank at this time. See general controls layout on Page 4 for location.
4. Disconnect wire leads to high limit control during this test.
5. Depress reset buttons to insure switch contacts are closed.
6. Set multi-meter to ohms setting. Check continuity through circuit A and B as showing in the illustrations below.
A) Continuity IS present, switch is okay.
B) Continuity NOT present, replace switch.

WARNING High voltage exposure. To avoid hazard to life or property, be sure power is turned OFF to water heater while performing this
procedure.

Observe heating cycle. N Does switch open? Y
Is water temperature Y over 196°F? N

Is water temperature over 196°F?

Y

Switch OK.

Replace switch.

High Limit Heating Cycle Flow Chart

NOTE Disconnect Wire Leads to Control

Circuit "A" Continuity Testing
20

Circuit "B" Continuity Testing

SERVICE PROCEDURE VII Thermostat Testing

Surface Mounted Thermostat. Operation Testing (NOT including 600V).
Water in Tank is Cold with Power ON.
1. This procedure assumes line voltage, ECO and elements are in working order.

WARNING High voltage exposure. To avoid hazard to life or property, use extreme caution when
making voltage checks.

2. Turn power "OFF" to water heater.

3. Remove access cover from lower control box. Remove insulation from inside of control box. Remove plastic cover from thermostat.

4. Turn power "ON" to water heater.

5. Set multi-meter to Volts AC.

6. Use caution and check voltage across terminals L1 and L3

ELEMENT

for all thermostats (see illustration 8).

Illustration 8

A) Rated voltage NOT present, check fuses and/or line voltage.

ELEMENT
Illustration 9

B) Rated voltage IS present, proceed to step 7.

7. Check across terminals L4 and T2 of thermostat (see illustration 9).

A) Rated voltage NOT present, recheck ECO. If ECO is okay, replace thermostat.

B) Rated voltage IS present, thermostat is calling for heat, go to step 8.

8. Check across element terminals (see illustration 10)

A) Rated voltage NOT present, check wire connections from thermostat to element. B) Rated voltage IS present, repeat element testing (see Page 15). Water in Tank is Above Thermostat Settings.

ELEMENT
Illustration 10

1. This procedure assumes line voltage, ECO and elements are in working order.

2. Turn power "ON" to water heater.

3. Set multi-meter to Volts AC.

4. See illustration 9, check across terminals L4 and T2 of thermostat.

A) Rated voltage IS present, replace thermostat.

B) Rated voltage NOT present, thermostat is okay.

C) Lower than rated voltage IS present, recheck for grounded element (see Page 15).

21

SERVICE PROCEDURE VIII Thermostat Testing

600V Surface Mounted Thermostat Models Operation Testing.
Water in Tank is Cold with Power ON.
1. This procedure assumes line voltage, ECO, transformer, thermostat, and elements are in working order.

WARNING High voltage exposure. To avoid hazard to life or property, use extreme caution when
making voltage checks.

2. Turn power "OFF" to water heater.

3. Remove access cover from lower control box. Remove insulation from inside of control box.

4. Using a phillips head screwdriver, disconnect the wire lead at terminal 2 of the thermostat. Only check one thermostat at a time to insure wires are correctly reinstalled upon completion. Mark wires if necessary for reinstallation.

5. Set multi-meter to check continuity.

6. Use caution and check continuity across terminals 1 and 2 for all thermostats (see illustration 11).
A) Continuity NOT present, replace thermostat. B) Continuity IS present, thermostat is okay.

Illustration 11

Water in Tank is Above Thermostat Settings.

1. This procedure assumes line voltage, ECO, thermostat, transformer, and elements are in working order.

2. Turn power "OFF" to water heater.

3. Remove access cover from lower control box. Remove insulation from inside of control box.

4. Using a phillips head screwdriver, disconnect the wire lead at terminal 2 of the thermostat. Only check one thermostat at a time to insure wires are correctly reinstalled upon completion. Mark wires if necessary for reinstallation.

5. Set multi-meter to check continuity.

6. Use caution and check continuity across terminals 1 and 2 for all thermostats (see illustration 11). A) Continuity NOT present, replace thermostat. B) Continuity IS present, thermostat is okay.

22

SERVICE PROCEDURE IX Thermostat Testing

Immersion Thermostat Operation Testing.
Thermostat Specification. Calibration: 184°F/176°F Max Differential: 6°F Operating Range: 80°F to 180°F

WARNING High voltage exposure. To avoid hazard to life or property, use extreme caution when
making voltage checks.

Providing the water temperature in tank is within the operating range of the thermostat, checking thermostat operation can be as simple as rotating the thermostat dial and listening to the contactor(s) to see if they respond to a call for heat.
Use caution and turn power "ON" and rotate the thermostat dial to call for heat. With water temperature below the thermostat setting, the contactor(s) close. With the contacts closed, use caution and check for rated voltage across lower terminals of contactor(s) (see illustration 12). If rated voltage is present, the thermostat is calling for heat.

L1 L2 L3 T1 T2 T3

Rotate thermostat dial to the minimum setting. With water temperature above the thermostat setting the contactor(s) will open. With the contacts open, voltage should not be present at lower terminals of contactor(s).
Thermostat Control Continuity Testing.

Check voltage across lower terminals of contactor(s)
Illustration 12

1. This procedure assumes line voltage, ECO and contactor(s) are in working order. 2. Turn power "OFF" to water heater.

3. Remove access cover from lower control box. Remove insulation from inside of control box.
4. Locate thermostat control (see general controls layout on Page 4) and remove wire leads to control screw terminals.

5. Water temperature in tank must be within operating range of thermostat for this test. If above or below,

it will be necessary to drain tank and remove thermostat immersion bulb from tank to warm or cool the

bulb to be within operating range of thermostat.

Thermostat Immersion Bulb

6. Set multi-meter to the "Ohms" setting.

7. Rotate thermostat dial to highest setting.

8. Check across screw terminals of control (see illustration 13).

A) Continuity NOT present, replace thermostat. B) Continuity IS present, proceed to step 9.

9. Rotate thermostat dial to lowest setting.
10. Check across screw terminals of control (see illustration 13). A) Continuity NOT present, thermostat is okay. B) Continuity IS present, replace thermostat.

NOTE: Disconnect Wire Leads to Control
Screw Terminals

Thermostat Dial

Illustration 13

23

SERVICE PROCEDURE X Contactor Testing

Contactor Operation Testing. Noisy Contactor.

WARNING High voltage exposure. To avoid hazard to life or property, use extreme caution when
making voltage checks.

Noisy or chattering contactor operation in most cases is due to voltage variations being supplied to the water heater. Extended periods of voltage variations will cause damage to the operating coil of the contactor causing noisy operation. Determine that service voltage to the unit meets the electrical requirements per the rating plate located on the front of the water heater.

In addition, debris between the contact plates will cause noisy operation.

Contactor Operating Coils.

Contactor operation is achieved by energizing an operating coil in response to a call for heat from the thermostat. There are three different operating coils used depending on voltage rating of the water heater as follows:

Description

Color Code

208/240 Volt Coil 277 Volt Coil 480 Volt Coil

Green Blue Black

All the coils have a color code for visual confirmation. In addition, the 277 and 480 volt coils are labeled with voltage rating for proper identification. All contactors supplied for replacement are equipped with the 208/240 volt operating coil. By removing the rear mounting plate of the contactor, the operating coils can be changed based on desired service voltage. When contactor replacement is required be sure to order the proper operating coil base on the voltage rating found on the rating plate located on the front of the water heater.

Rear Mounting Plate

Operating Coil

Color Code Location Identification Label Location

24

SERVICE PROCEDURE X Contactor Testing

Contactor Operation Testing (continued).
This procedure assumes control circuit is operating correctly.
Providing the water temperature in tank is within the operating range of the thermostat, checking contactor operating can be as simple as rotating the thermostat dial and listening to the contactor(s) to see if they respond to a call for heat.

WARNING High voltage exposure. To avoid hazard to life or property, use extreme caution when
making voltage checks.

1. Turn power "ON" and rotate thermostat dial to the maximum setting. With water temperature in tank below the thermostat setting the contactor(s) will close. With the contacts closed, check for line voltage across operating coil terminals (see illustration 14).

A) Line voltage IS present, go to step 2.

B) Line voltage NOT present, verify control circuit operation.

2. Check for rated voltage across lower terminals of contactor(s) (see illustration 15).
A) Rated voltage IS present, go to step 3.

Illustration 14

B) Rated voltage NOT present, replace contactor.

3. Rotate thermostat dial to the minimum setting. With water temperature in tank above thermostat setting, the contactor(s) will open. With the contacts open, voltage should not be present at lower terminals of contactor(s).
4. Check for line voltage across operating coil terminals (see illustration 14).
A) Line voltage IS present, verify control circuit operation.

L1 L2 L3 T1 T2 T3

B) Line voltage NOT present, go to step 5.

5. Check for rated voltage across lower terminals of contactor(s) (see illustration 15).
A) Rated voltage IS present, replace contactor.

Check voltage across lower terminals of contactor(s)
Illustration 15

B) Rated voltage NOT present, contactor is okay.

25

SERVICE PROCEDURE XI
Thermostat Removal and Replacement

Surface Mounted Thermostat Removal and Replacement
1. STOP, DANGER! Turn power "OFF" to water heater.
2. Remove access cover from lower control. Remove insulation from inside of control box. Remove plastic cover from thermostat.

WARNING High voltage exposure. To avoid hazard to life or property, be sure power is turned OFF to water heater while performing this
procedure.

3. Disconnect wires from thermostat terminals. It may be necessary to label wires for proper reconnection to new thermostat.

4. Note thermostat temperature setting for proper setting of new thermostat.

5. Slide thermostat upwards and out of mounting bracket.

6. Use a stiff brush to remove any debris or loose scale from tank surface where new thermostat will be installed.

7. Slide new thermostat down into thermostat bracket until it snaps into place. IMPORTANT - thermostat must set completely flat or flush to tank surface. An improperly installed thermostat will cause improper water heater operation.

8. Refer to the wire diagram located on the inside of the upper control box cover and reconnect wires to the thermostat. Be sure wire connections are snug and corrosion free. Do not over tighten as that may damage thermostat.

9. Set thermostat to the original thermostat setting found on the old thermostat.

10. Restore power to water heater and verify proper heater operation.

Tank Surface
Thermostat
Thermostat mounting bracket

Proper Thermostat mounting flush with tank surface
Improper Thermostat mounting. Thermostat not flush with tank surface

Front View Thermostat Mounting
26

Side View Proper Thermostat
Mounting

Side View Improper Thermostat
Mounting

SERVICE PROCEDURE XII
Thermostat Removal and Replacement

Immersion Thermostat Removal and Replacement
1. STOP, DANGER! Turn power "OFF" to water heater.
2.Turn off cold water supply to heater. Connect hose to drain spigot of water heater and route to an open drain. Open a nearby hot water faucet to vent heater for draining. Open drain spigot of water heater and allow water heater to drain to a point below the immersion bulb location (see illustration 16).

WARNING High voltage exposure. To avoid hazard to life or property, be sure power is turned OFF to water heater while performing this
procedure.

3. Close drain spigot and remove hose.

4. Remove lower control box cover and insulation.

5. Locate thermostat inside lower control box mounted to the right side of the box below the ECO control (see illustration 16).

6. Follow copper capillary tube from thermostat to the immersion bulb location and remove immersion bulb from tank using 11/16" wrench.

Immersion Thermostat Bulb
Location

7. Remove (pull) thermostat control dial from stem of thermostat.
8. Remove the two thermostat mounting screws located under thermostat dial (see illustration 16).
9. Once thermostat is removed, disconnect wire leads to the thermostat. NOTE: It may be necessary to identify wires for proper reconnection to new thermostat.

Copper Capillary Tube
Immersion Thermostat
Control

ECO Control
Thermostat Control Mounting Screws Located Under Thermostat Dial

10. Refer to wiring diagram located on the inside of the upper control box cover and properly reconnect wire leads to new thermostat and remount control inside control box using screws from step 8.

11. Replace control dial to stem of thermostat.

Illustration 16

12. Loosen ferrule nut of immersion bulb (see illustration 17).

Immersion Bulb

Ferrule Nut

Tank Nut

Copper Capillary
Tube

Illustration 17
13. Position tank nut at end of immersion bulb as shown in illustration 17. Insert immersion bulb into tank and tighten tank nut.

14. Gently pull copper capillary tube to insure the immersion bulb is in a horizontal position as shown in illustration 17 and tighten ferrule nut.

15. Resume water supply, full tank and check for leaks.

16. Be sure tank is full of water and resume power supply to water heater. Verify proper thermostat operation.

27

SERVICE PROCEDURE XIII
Contactor Model High Limit (ECO) Control
Removal and Replacement

Contactor Model High Limit (ECO) Control Removal and Replacement.
1. STOP, DANGER! Turn power "OFF" to water heater.
2.Turn off cold water supply to heater. Connect hose to drain spigot of water heater and route to an open drain. Open a nearby hot water faucet to vent heater for draining. Open drain spigot of water heater and allow water heater to drain to a point below the immersion bulb location (see illustration 18).

WARNING High voltage exposure. To avoid hazard to life or property, be sure power is turned OFF to water heater while performing this
procedure.

3. Close drain spigot and remove hose.

4. Remove lower control box cover and insulation.

5. Locate ECO Control inside lower control box mounted to the right side of the box above the thermostat control (see illustration 18).

6. Follow copper capillary tube from ECO Control to the immersion

bulb location and remove immersion bulb from tank using 11/16" wrench.

ECO Immersion Bulb
Location

7. Remove the two ECO control mounting screws located outside

the lower control box.

8. Once ECO control is removed, disconnect wire leads to the

Copper Capillary Tube

control. NOTE: It may be necessary to identify wires for proper

reconnection to new control.

ECO Control
Thermostat Control

9. Refer to wiring diagram located on the inside of the upper control box cover and properly reconnect wire leads to new ECO control and remount control inside control box using screws from step 7.

10. Loosen ferrule nut of immersion bulb. (see illustration 19).

Immersion Bulb

Ferrule Nut

Illustration 18

Tank Nut
Illustration 19

Copper
Capillary Tube

11. Position tank nut at end of immersion bulb as shown in illustration 19. Insert immersion bulb into tank and tighten tank nut.
12. Gently pull copper capillary tube to insure the immersion bulb is in a horizontal position as shown in illustration 19 and tighten ferrule nut.
13. Resume water supply, full tank and check for leaks.
14. Be sure tank is full of water and resume power supply to water heater. Verify proper ECO operation.

28

SERVICE PROCEDURE XIV
600V Model High Limit (ECO) Control
Removal and Replacement

600V Surface Thermostat Model High Limit (ECO) Control Removal and Replacement.
1. STOP, DANGER! Turn power "OFF" to water heater.
2. Remove lower control box cover and insulation.
3. Locate high limit switch (ECO) mounted to the tank above the element spuds (see illustration 20).

WARNING High voltage exposure. To avoid hazard to life or property, be sure power is turned OFF to water heater while performing this
procedure.

4. Disconnect wire leads to the ECO. NOTE: It may be necessary to identify wires for proper reconnection to the new control.

5. Remove the two ECO mounting nuts holding the sensor to the tank. Take care not to damage the mounting studs.

6. Fasten the replacement ECO to the tank using the nuts from step 5. Take care not to damage the mounting studs. Refer to wiring diagram located on the inside of the upper control box cover and properly reconnect wire leads to new ECO.

High Limit Switch

7. Verify proper ECO operation.

Mounting Stud

Illustration 20

29

SERVICE PROCEDURE XV
Heating Element Removal
and Replacement

Heating Element Removal and Replacement.
1. STOP, DANGER! Turn power "OFF" to water heater.
2. Turn off cold water supply to heater. Connect hose to drain spigot of water heater and route to an open drain. Open a nearby hot water faucet to vent heater for draining. Open drain spigot of water heater and allow heater to drain to a point below the element(s).

WARNING High voltage exposure. To avoid hazard to life or property, be sure power is turned OFF to water heater while performing this
procedure.

3. Close drain spigot and remove hose.
4. Remove access cover and insulation from lower control box. Remove plastic cover from thermostat.
5. Disconnect wires from element terminals.
6. Remove element from tank using 1-½" deep well socket or appropriate wrench. Unscrew element counter-clockwise to remove from tank.

WARNING Heater components and stored water may be HOT when performing the following steps in this procedure. Take necessary precaution to
prevent personal injury.

7. Be sure to remove old element gasket from the tank. It is recommended to replace the gasket with a new one.

8. Check new element terminal block for proper electrical rating. NOTE: Some elements have dual ratings, be sure to check all surfaces of the element terminal block (see illustration 21).

9. Apply new element gasket to the new element. Be sure gasket is seated flat against element flange without rolls or gaps (see illustration 21).

10. Clean any debris from element fitting on tank.

11. Thread new element clockwise into tank. Tighten element using 1-½" deep well socket or appropriate wrench. Do not over tighten, over tightening may damage element gasket.

12. Reconnect wires to element. Be sure connections are snug and corrosion free. Do not over right as that may damage terminal block.

13. Resume water supply to heater. Be sure tank is full of water and check for leaks.

14. Reinstall plastic thermostat protector(s).

15. Reinstall insulation and control box cover.

16. To resume operation BE SURE TANK IS FULL OF WATER and restore power to water heater. Verify proper heater operation.

Date Code

Element Rating. Example: (4500 Watt, 240 Volt)
Element Flange
Element Gasket Seated Flat Against Element Flange Without Rolls or Gaps

0642 4500W 240V RC02404524

Terminal Block

Manufacturer Identification
Illustration 21

30

SERVICE PROCEDURE XVI
Anode Rod Inspection and Replacement

Anode Rod Inspection and Replacement.
1. STOP, DANGER! Turn power "OFF" to water heater.
2. Turn off cold water supply to heater. Connect hose to drain spigot of water heater and route to an open drain. Open a nearby hot water faucet to vent heater for draining. Open drain spigot of water heater and allow heater to drain to a point below the anode rod locations at the top of the tank.
3. Close drain spigot and remove hose.
4. Remove the plastic anode rod access plugs at the anode rod locations.
5. Remove anode rods from the water heater using a 1-1/16" socket wrench.

WARNING High voltage exposure. To avoid hazard to life or property, be sure power is turned OFF to water heater while performing this
procedure.
WARNING Heater components and stored water may be HOT when performing the following steps in this procedure. Take necessary precaution to
prevent personal injury.

6. Visually inspect anode rods. Anode rods should show signs of depletion, this is normal. If depletion is 1/2 of the original anode rod diameter (original diameter is approximately ¾"), replacement is recommended. If any of the steel core of the anode rod is exposed, replacement is recommended.

7. Upon completion of inspection and/or subsequent replacement of the anode rod, reinstall the anode into the water heater, resume water supply, refill water heater with water and check for leaks.

8. To resume operation, BE SURE TANK IS FULL OF WATER and turn power "ON" to water heater.

Anode Rod Locations

31

TERMINAL BLOCKS

FUSE BLOCKS

CONTACTORS

GENERIC PARTS LIST
FUSES

31

32

33

39 36

37

40

41

CONTACTOR COILS

34

35

35

38

1

30

42 2

43

44

45

GROUND LUGS

46

47

48

TRANSFORMER (600V ONLY)

50

29 28 49
27 5A
26 25

20 21 22 23
24

19 18

17 16 15 14

3

3A

4

8

4A

7

6

5

9

10 10A 11/11A 12/12A 13

32

GENERIC PARTS LIST

Item 1 2 3 3A 4 5 5A 6 7 8 9 10 10A 11 11A 12 12A 13 14 15 16 17 18 19 20 21 22 23

Description Anode Rod Hot Water Outlet Nipple T&P Nipple T&P Coupling T&P Relief Valve High Limit Switch Surface High Limit Switch Hex Nut Lock Washer Screw High Limit Spacer Cleanout O-Ring Cleanout Gasket (ASME) Cleanout Cover Cleanout Cover (ASME) Cleanout Cover Screw Cleanout Cover Screw (ASME) Cleanout Access Cover Brass Drain Valve Escutcheon Drain Extender Thermostat Dial Screw Immersion Thermostat Heating Element Surface Thermostat Bracket Surface Thermostat Surface Thermostat Cover

Item 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Description Lower Control Box Cover Heating Element Plug Heating Element Gasket Cold Water Inlet Nipple Plastic Snap Bushing Lower Control Box Upper Control Box Terminal Block (Block A) Terminal Block End (used for Block A) Terminal Block 2 Pole Terminal Block 3 Pole Screw Fuse Block 2 Pole, Class G Fuse Block 3 Pole, Class G Fuse Block 3 Pole, Class J Contactor 3 Pole Contactor 4 Pole Screw Contactor Coil Fuse, Class G Fuse, Class J Fuse, Class J Ground Lug Small Ground Lug Large Screw ¾" NPT Plug Transformer - 120V

Glossary of Terms

Term Voltage Current Resistance Energy Power

Definition Electrical potential Rate of voltage flow Ability of a device to dissipate power irreversibly Ability to do work Energy per unit of time

Unit of Measure Volts Amperes (amp) Ohms kW/hr, Joule Watts, kW, VA

One Kilowatt (1kW) = 1,000 Watts = 3,412 BTU DC = Direct Current AC = Alternating Current Hz = Hertz °F = Degrees Fahrenheit °C = Degree Centigrade

BTUH = British Thermal Units per Hour PSI = Pounds per Square Inch GPM = Gallons per Minute GPH = Gallons per Hour ECO - Energy Cut Off NPT - National Pipe Thread ASME - American Society of Mechanical Engineers

33

NOTES
34

NOTES
35

Madison, Wisconsin
For U.S. and Canada field service, contact your professional installer or local Bock Water Heaters sales representative
Sales/608-227-3311 Fax/608-327-3311
Application & Sizing/608-227-3311 Fax/608-327-3311
Technical Support/888-784-8322 Fax/610-683-9208
Warranty/608-227-3319 Fax/608-327-3300
Email [email protected]
www.bockwaterheaters.com


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