Bradford White 6A User manual

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Manual 238-47202-00A
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
6A, 12A, 20A, 30A, 40A, 50A, 80A, 120A
ASME SERIES IMMERSION THERMOSTAT
WITH CONTACTORS
COMMERCIAL ELECTRIC ENERGY SAVER
WATER HEATER
®

Table of Contents
Page Service Procedure
Introduction ………………………………………………………………………. 2 - - -
Tools……………………………………………………………………………… 2 - - -
General Information ……………………………………………………………… 3 - - -
Sequence of Operation …………………………………………………………… 10 - - -
Troubleshooting ………………………………………………………………….. 13 - - -
Heating Element Testing ……………..................................................................... 15 ACE-I
Line Voltage Testing………………...…………………………………………… 16 ACE-II
Fuse Testing…......................................................................................................... 17 ACE-III
High Limit (ECO) Testing……………………………………………………..…. 18 ACE-IV
Immersion Thermostat Operation Testing………................................................... 19 ACE-V
Contactor Operation Testing……………………………………………………… 20 ACE-VI
Immersion Thermostat Removal and Replacement…………….………………… 21 ACE-VII
High Limit (ECO) Removal and Replacement……………..…………………….. 22 ACE-VIII
Heating Element Removal and Replacement …………………………………….. 23 ACE-IX
Anode Inspection and Replacement ……………………………………………… 24 ACE-X
Generic Parts List ………………………………………………………………… 25 - - -
Glossary of Terms…………………………………………………………………. 26 - - -
Page 2
This service manual is designed to aid service and maintenance professionals on the function, proper diagnosis and repair of
Bradford White Commercial Electric Water Heaters.
The text and illustrations in this manual provide step by step instructions to facilitate proper operation and troubleshooting
procedures. Contact the Bradford White Technical Support Group immediately if diagnosis can not be made using the
methods described in this service manual.
Introduction
ASME Series
Commercial Electric Water Heaters
Tools
- Multi Meter. - Phillips Head Screw Driver.
- 2-1/8" Deep Well Socket. - Common Screw driver.
- 1-1/16" Deep Well Socket. - Thermometer.
- ¼" Nut Driver. - Drain Hose.
- Other Hand Tools: Pipe Wrench, Channel Locks, Pliers (common & needle nose), Wire cutters, Wire Strippers,
Allen Wrench Set, Flash Light.
2

GENERAL INFORMATION
120A - 24 - 3 - 108B - BBG
Pressure Gage Option.
Control Circuit Option Code.
Any combination of the following optional controls:
- Heating Element Time Delay Sequencing.
- Low Water Power Interrupt.
- Panel Door Interlock
- High Pressure Power Interrupt
- Low Pressure Power Interrupt
- Alarm Horn
Power Circuit Code.
- Voltage
- kW Rating
- Phase
- Amp Rating
Warranty
Tank
BRADFORD WHITE CORPORATION
200 LAFAYETTE ST. MIDDLEVILLE MI 49333
Model No: 120A-24-3-108B-BBG
Serial No: ZB2564812
Cap. 120(gal.)/454.2(liters)
Press: Test 300(psi), Working 150(psi)
Volts 240 Max Temp 180°
Phase Single Amps 100
kW Each 6 Total kW 24 4 Elements
Wattage Rating Based Upon 60 Hz
Page 3
Typical Rating Plate
Located On Front Of Water Heater
Model Number
Electrical Characteristics
Model Number Breakdown
kW Rating
In the Field, this information
is obtained from the heaters
rating plate
NOTE: Code “AA”
denotes no optional
controls used.
3

Page 4
GENERAL INFORMATION
General Controls Layout
Pressure
Gage
(optional)
Control Circuit
Transformer
Thermostat
Control
Heating Element
Time Delay
Sequencers
(optional)
Terminal strip
High Limit
(ECO)
Power Circuit
Fuse Blocks
Terminal
Block
Control Circuit
Fuse Block
Contactors
High Limit
Immersion Bulb
Thermostat
Immersion
Bulb
Heating
Element
Alarm
Horn
(optional)
Alarm
Horn Relay
(optional)
Low Water
Level Control
(optional)
Low Pressure
Limit Switch
(optional)
High Pressure
Limit Switch
(optional)
Contactor
Terminal connections to the
fuse block and/or terminal block
Terminal connections to the
heating elements
Terminal connections of
contactor operating coil.
Contactor operation is achieved by energizing a 120 volt operating coil located within the contactor 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. Optionally, time delay sequencers may be used to stage contactor activation thereby reducing the
inrush of current to the water heater.
Standard Controls
4

GENERAL INFORMATION
Page 5
Immersion Style Thermostat Control
Immersion Thermostat Control
Standard Controls (continued)
Direct
Immersion
bulb
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.
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 over
heated water has been determined, The control must be manually
reset to restore normal operation.
Immersion Style High Limit (ECO) Control for
Contactor Models
Direct
Immersion
bulb
Manual Reset
Buttons
5

Page 6
GENERAL INFORMATION
Optional Controls
High and Low Water Pressure Controls-
These controls interrupt the electrical current to the contactor coil when the pressure settings are exceeded. The
operation and setting of these controls are described in the manual provided by the control manufacturer. This manual is
included with the water heater Installation and Operating Instruction manual provided with the water heater.
The pressure settings for these controls are adjustable. These controls are specified for use when the installation has
unique pressure requirements that must be safeguarded. Therefore, before adjusting the pressure values, it is
recommended that you consult the person responsible for the facility that the water heater is servicing.
The electrical connections are referenced in the Control Circuit Wiring Diagram and in the pressure control manual
provided by the control manufacturer. Refer to these instructions when servicing the controls.
2-1/8 Hex
Screw-in Flange
Terminal Block
Screw
Terminal Block
Zinc Plated Copper or
Incoloy Sheath
Element Rating Ink Stamped
on face of Terminal Block.
Direct Immersion “Screw-in” Type Heating Element
Standard Controls (continued)
Certain control components are available as “Optional“. When these optional components are installed with the water
heater, the control circuit wiring diagram accordingly will include these components. The optional equipment available
from the manufacturer includes the following:
-High Water Pressure Switch -Heating Element Time Delay Sequencers
-Low Water Pressure Switch -Electrical Door Lock
-Low Water Level Switch -Alarm Horn
6

GENERAL INFORMATION
Optional Controls (continued)
This control will interrupt the electrical current to the contactor coil when a low water level condition is sensed inside the
water heater tank. When the low water level condition is corrected the control will automatically sense the new situation
and electrical current will again energize the contactor coil. Normal water heater operation will be resumed.
To remove the low water level control from the tank you must first loosen the control by un-threading it from the tank
fitting and then rotating the control until the arrow printed on the side of the hex fitting is pointing downward. This will
enable the float orientation to align itself with the opening in the tank-fitting.
Low Water Level Control-
When installed, refer to the direction of the arrow on the hex and insure that it is pointing upwards. If it is not pointing
upward, the control switch will not activate when the tank is refilled with water. Refer to illustration below for clarification.
Heating Element Time Delay Sequencers-
Heating element sequencers are available in order to stage the activation of the heating elements thereby, reducing the
inrush of electrical current to the water heater. The sequencers will control one or more contactor coils depending upon
the water heater voltage, phase, and KW.
One contactor will be energized immediately when there is heating demand, the second contactor, controlled with a
sequencer, will be activated approximately 20 seconds later, and the third contactor will be activated in another 20
seconds thereby, staging the three contactors over the 40 second time period. The staging occurs in a similar manner
for applications having more than three contactors.
Refer to the Control Circuit Wiring Diagram for the specific application being serviced.
Note: On the occasion of servicing the water heater where frequent restarts in a short time interval are encountered (i.e.
on, off, on, etc.), the timing sequences will not begin until the sequencers have experienced a time interval to reset.
Page 7
7

GENERAL INFORMATION
Optional Controls (continued)
Electrical Door lock-
An electrical door lock is offered in order to secure the access to the water heater control cabinet. This device will lock
the control cabinet door when the 120VAC control circuit voltage is applied to it.
Note: Once the door is opened, the water heater can be re-energized, if necessary, for service diagnosis.
Alarm Horn-
The Alarm Horn is an option specified when the installation desires an audible signal to immediately sound an alert
when the water heater operation is interrupted for certain faults. Referring to the control circuit wiring diagram, the alarm
will activate when any one of the following events occur:
The Hi-Limit control has been tripped
The High Water Pressure Control senses excessive pressure
The Low Water Pressure Control senses insufficient pressure
The Low Water Level Control senses an insufficient quantity of water
The alarm will sound only for the options specified (i.e. if a low water level control is not specified then the alarm will not
recognize a low water level condition).
Horn Relay
Horn Relay
Internal Wiring
Page 8
Combination Temperature and Pressure Gage-
A non-electrical device to visually reference water temperature and internal tank pressure.
8

GENERAL INFORMATION
Watts
Volts x 1.732
Watts = Amps x Volts Volts
Watts
2
Commonly Used Formulas
240V 1Ph
Ungrounded
Ungrounded
Grounding
BLACK
RED
GREEN
240
120
Common Service Wire
Configurations
Page 9
120
(balanced 3 phase)
Amps =
Watts
Volts
(Single phase)
Amps = Ohms =
120
ABCNeutral
RED BLACK RED
120
120 208
208 208
208 3Ph
120
ABCNeutral
RED BLACK RED
120
120 240
240 240
240 3Ph
277
ABCNeutral
RED BLACK RED
277
277 480
480 480
480 3Ph/277 1Ph
Full Load Current Amps
208 Volt
1 Ph 3 Ph
6
kW
9
12
13.5
15
18
24
27
30
36
45
54
28.8 16.6
43.2 25.0
57.6 33.3
64.9 37.5
72.1 41.6
86.5 50.0
115.4 66.7
129.8 75.0
144.2 83.3
173.0 100.0
216.3 125.0
259.6 150.0
240 Volt 277 Volt 380 Volt 415 Volt 480 Volt
25.0 14.4
37.2 21.6
50.0 28.9
56.2 32.5
62.5 36.1
75.0 43.4
100.0 57.8
112.5 65.0
125.0 72.2
150.0 86.7
187.5 108.3
225.0 130.0
12.5 7.2
18.7 10.8
25.0 14.4
28.1 16.2
31.2 18.0
37.5 21.6
50.0 28.9
56.2 32.5
62.5 36.1
75.0 43.3
93.7 54.1
112.5 65.0
1 Ph
21.6
32.4
43.3
48.7
54.1
64.9
86.6
97.4
108.3
129.9
162.4
194.9
3 Ph
8.3
12.5
16.7
18.8
20.9
25.0
33.4
37.5
41.7
50.1
62.6
75.1
3 Ph
9.1
13.6
18.2
20.5
22.7
27.3
36.4
41.0
45.6
54.7
68.4
82.0
1 Ph 3 Ph 1 Ph 3 Ph
314.4 -12.5 -6.3 -10.8 --
81 389.4 224.8 337.5 194.8 168.7 97.4292.4 112.6123.1
600 Volt
3 Ph
5.7
8.66
11.5
13.0
14.4
17.3
23.1
26.0
28.8
34.6
43.3
52.0
-
78.0
9

SEQUENCE OF OPERATION
This water heater has two distinct electrical systems. One system, referred to as the “Control Circuit”, controls the
water heater operation, while the other system referred to as the “Power Circuit”, connects the electrical power to the
heating elements, The electrical contactors interconnect these two systems. In order to clearly illustrate the electrical
circuits, two wiring diagrams are provided. These diagrams are labeled as the “Control Circuit Wiring Diagram” and the
“Power Circuit Wiring Diagram” and they are attached to the surface of the panels inside the water heater control
cabinet.
The control circuit operates with 120VAC electrical service. This voltage is provide by the multi-tap transformer which
has the primary coil connected to the field wiring that is serving the water heater. The Transformer, Thermostat, Hi-Limit
control, and the Contactor Coil are always included in the Control Circuit.
Control Circuit Description-
Certain other control components are available as “Optional“. When these optional components are installed with the
water heater, the control circuit wiring diagram accordingly will include these components. The optional equipment
available from the manufacturer includes the following:
High Water Pressure Switch
Low Water Pressure Switch
Low Water Level Switch
Alarm Horn
Heating Element Sequencers
Electrical Door Lock
Control Circuit Wire Diagram
4When the thermostat calls for heat, contacts close
inside the thermostat completing the circuit and
energizing the contactor coil.
The energized contactor coil causes the contactor to
close energizing the heating elements.
5
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.
6The de-energized contactor coil causes the contactor
to open, interrupting current flow through the Heating
elements.
7
Page 10
NOTE: To help understand the concept of the operating sequence,
the control circuit shown is without any optional controls. See page
11 For control circuit showing all available optional controls
Control Circuit Sequence of Operation-
Line voltage from
power circuit
1Line voltage is applied to control circuit fuse block.
2Line voltage continues to transformer with one leg of
voltage connecting to the common terminal and the
other leg connecting to the appropriate line voltage
multi-tap terminal. Transformer output (always 120
volts) continues to high limit (ECO) control.
3Hi limit (ECO) control is closed so one leg of 120 volts
continues to one side of the contactor coil. The other
leg is connected to the thermostat.
Appropriate line
voltage multi-tap
terminal
10