Bradford-White M430T'F(BN User Manual

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Flammable Vapor Ignition Resistant Water Heater

SERVICE

MANUAL

Troubleshooting Guide and Instruction for Service

(To be performed ONLY by qualified service providers)

For the Bradford White

Defender Safety System

Models:

MI30T*F(BN,CX)2

M430T*F(BN,CX)2

MI30S*F(BN,CX)2

M4403S*F(BN,CX)2

MI303T*F(BN,CX)2

M4403T*F(BN,CX)2

MI40T*F(BN,CX)2

M450S*F(BN,CX)

MI403S*F(BN,CX)2

M1XR403S*F(BN,CX)2

MI404T*F(BN,CX)2

M1XR504T*F(BN,CX)2

MI503*F(BN,CX)2

M2XR504T*F(BN,CX)2

MI50L*F(BN,CX)2

M2C504T*F(BN,CX)

MI504S*F(BN,CX)2

50T65F(BN,CX)

 

(*) Denotes Warranty Years.

Manual 44943A

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Flammable Vapor Ignition Resistant Water Heater

Table of Contents

 

Page

Service Procedure

Introduction

3

- - -

Trouble shooting Chart

4

- - -

Inner Door Gasket Removal, Inspection, Replacement and Installation

5

RG-I

Thermocouple Testing and Replacement

8

RG-II

Pilot Assembly Inspection Cleaning and Replacement

10

RG-III

Piezo Igniter and Electrode Testing

11

RG-IV

Combination Thermostat/Gas Valve Testing and Replacement

12

RG-V

Burner Operation Inspection, Adjustment, Cleaning and Replacement

17

RG-VI

Resettable Thermal Switch Testing and Replacement

20

RG-VII

ScreenLok Flame Arrestor Cleaning

22

RG-VIII

Dip Tube and Anode Inspection and Replacement

23

RG-IX

Generic Parts List

25

- - -

2

Introduction

The Bradford White DEFENDER Safety System

The Bradford White DEFENDER Safety SystemTM was designed to resist the ignition of flammable vapors that can occur outside of the water heater. Use and installation are nearly identical to previous versions of atmospherically fired and vented water heaters. A number of exclusive design features are incorporated in the system that will require additional knowledge on the part of the qualified service provider. The following information will instruct service professionals on the function, proper diagnosis and repair of water heaters employing the Bradford White DEFENDER Safety System .

How the Safety System Works

During normal operation, air for combustion is drawn into the water heater through the openings in the jacket. This air travels down and around the combustion chamber and enters through holes in the very bottom of the corrosion-resistantcombustion chamber. The air then travels up through the oriented flame arrestor plate louvers, where the velocity of the air is increased and its direction altered. The air then mixes in a normal manner with supplied gas and is efficiently combusted, producing very low NOx emissions. In the unlikely event trace amounts of flammable vapors are present in the air flowing into the combustion chamber, the vapors are harmlessly ignited by the burner / pilot flame. If flammable vapors are in sufficient quantity to prevent normal combustion, the burner / pilot flame is shut down. Should the flammable vapors continue to burn, the flame arrestor plate prevents the flames from traveling backwards and igniting vapors outside of the combustion chamber. The calibrated, multipurpose thermal switch recognizes this and shuts down the pilot and main burner. This switch also deactivates the burner and pilot in the unlikely event of restricted airflow caused by severe lint, dust or oil accumulation on the arrestor plate. If accumulation occurs, the ScreenLok flame arrestor can be easily cleaned and when the inner door is properly secured the unit can then be placed in operation. A cleaning procedure is included in this service manual.

3

Troubleshooting Chart

Flammable Vapor Ignition Resistant Water Heaters

SYMPTOM

 

PROBABLE CAUSE

CORRECTIVE ACTION

SERVICE

 

PROCEDURE

 

 

 

 

 

 

 

 

 

1. No incoming gas or too

1. Turn on gas supply and/or check line pressure.

1. See Service Procedure

 

 

low gas pressure.

RG-V,Page 12.

 

 

2. Review lighting instruction.

 

2.

Gas control knob set

 

 

Set combination/thermostat gas valve to correct

4. See Service Procedure

 

 

to wrong position.

 

 

position.

Pilot Will

3.

Pilot light button not being fully

RG-III,Page 10.

3. Review lighting instruction. Fully depress pilot

Not Light

 

depressed when attempting to

lighting button.

5. See Service Procedure

 

light pilot.

 

4. Clean, repair or replace.

 

4.

Pilot orifice or pilot tube is

RG-III,Page 10.

 

5. Verify correct electrode position.

 

 

obstructed or kinked.

 

 

 

Replace pilot assembly.

6. See Service Procedure

 

5.

Pilot electrode not sparking to pilot.

 

6. Replace Piezo igniter.

 

6.

Piezo igniter not functioning.

RG-IV,Page 11.

 

 

 

 

 

 

 

 

1. Poor thermocouple connection at

1. Check connection at combination thermostat/gas

 

 

valve. Proper tightness should be finger tight

 

 

 

combination thermostat/gas valve.

plus 1/4 turn.

 

 

2.

Thermocouple not fully engaged in

2. Inspect thermocouple to ensure that it is fully

4. See Service Procedure

Pilot will not

 

pilot assembly bracket.

engaged into pilot bracket.

 

RG-II,Page 8.

3.

Pilot flame is not fully enveloping the

3. Adjust tip of thermocouple to be fully engulfed

stay lit when

 

thermocouple “hot” junction.

by pilot flame.

5. See ServiceProcedure

4.

Weak or defective thermocouple.

4. Check thermocouple and replace if necessary.

button is

5.

Open ECO on combination

5. Check ECO continuity and replace combination

RG-V,Page 13.

released

 

thermostat/gas valve.

thermostat/gas valve if necessary.

6. See Service Procedure

6.

Defective magnet in combination

6. Check magnet operation and replace

 

RG-V,Page 13.

 

 

thermostat/gas valve.

combination thermostat/gas valve if necessary.

 

 

 

 

7. Resettable thermal switch has

7. Determine cause of switch activation. To reset,

 

 

 

opened.

depress button on resettable thermal switch

 

 

 

 

located on inner door.

 

 

 

 

 

 

1. Combination thermostat/gas valve

 

2. See Installation

 

 

set too low for desired water temp.

1. Adjust temperature dial on combination

Pilot will light

 

& operation manual.

2.

Combination thermostat/gas valve

thermostat/gas valve.

but the main

 

temperature is satisfied.

2. Check temperature dial setting on combination

3. See Service Procedure

3.

Insufficient gas supply or low gas

thermostat/gas valve.

burner will

 

pressure.

3. Check gas supply and line pressure.

RG-V,Page 12.

4.

 

not come on

Combination thermostat/gas valve

4. Check combination thermostat/gas valve for

4. See Service Procedure

 

has wide differential or is out of

proper operation, replace if necessary.

 

 

calibration.

 

RG-V,Page 12.

 

 

 

 

 

 

 

 

 

Pilot goes out

 

 

1. Verify adequate combustion air is available to the

 

periodically

 

 

unit. Check and clear Jacket slot openings of any

 

1. Insufficient combustion air supply.

dirt, dust, restrictions or other obstructions.

1. See Service Procedure

(after heating

2.

Incorrect, clogged vent system/ vent

Inspect flame arrestor plate and clean with stiff

RG-VIII,Page 22.

cycles, once a

 

terminal or location.

bristled brush and/or vacuum to remove any

 

3.

Inconsistent gas supply or gas

debris accumulation.

3. See Service Procedure

day, once a

 

pressure.

2. Check venting for proper sizing and proper

RG-V,Page 12.

 

 

operation

 

week etc.)

 

 

3. Check gas supply and line pressure.

 

 

1. Combination thermostat/gas valve

1. Check dial on combination thermostat/gas valve.

 

 

 

set too low for desired water temp.

2. Extremely cold water going into the heater will

 

 

2.

Cold inlet water temp. is very cold.

decrease the amount of hot water produced.

5. See Service Procedure

Not enough

3.

High demand periods.

It may be necessary to temper incoming water

RG-V,Page 12

4.

Incorrectly sized water heater for

supply.

 

hot water

5.

application.

3. Adjust high demand usage.

6. See Service Procedure

 

Combination thermostat/gas valve is

4. Contact Plumbing professional.

RG-IX,Page 23

 

 

out of calibration/not functioning.

5. Check combination thermostat/gas valve for

 

 

6.

Out of spec dip tube is diluting hot

proper operation, replace if necessary.

 

 

 

water with cold water.

6. Inspect dip tube and replace if necessary.

 

 

 

 

 

 

4

SERVICE PROCEDURE RG-I

Inner Door/Gasket Removal, Inspection

Replacement and Reinstallation

Inner Door Removal Procedure

Step 1. Rotate knob of the combination thermostat/gas valve to the “OFF” position. Step 2. Remove outer jacket burner access door

Step 3. Inner Door Removal.

a)Disconnect resettable thermal switch wire leads (leading from combination thermostat/gas valve).

b)Remove (2) 1/4" hex drive screws from right side inner door.

c)Remove (2) 1/4" drive screws from flange section of inner door.

d)Remove (2) 1/4" drive screws from left side inner door.

e)Remove inner door and inspect per step 4.

Resettable Thermal Switch

Wire Connection

1/4" Hex Drive Screws at

Flange Area of Inner Door

1/4" Hex Drive Screws

Right and Left Side Inner Door

Step 4.

Fully inspect inner door gaskets for the following:

 

>Tears

>Other imperfections that will inhibit proper seal

 

>Missing Material

>Gasket adhesion to inner door

 

>Cracks

>Material left on combustion chamber (around opening)

 

>Dirt or debris

 

If the gasket is not effected by any of the above, gasket replacement is not required.

If replacement is required, proceed to Inner Door Gasket Replacement Procedure.

Inner Door Gasket Replacement Procedure

! WARNING

If the information in these instructions is not followed exactly, a fire or explosion may result causing property damage, personal injury or death.

Step 5. After inspection of inner door as noted in step 4, completely remove gasket and adhesive residue from right and left side inner doors as needed.

Step 6. Use RTV sealant (recommended bead size 1/8") to secure the inner door gasket to the inner door sections (right & left). Refer to illustration on next page for proper application. Note the overlap configuration in the flange area of the inner door. Set the flange section first, this will help to achieve the proper over lap position.

5

SERVICE PROCEDURE RG-I

Inner Door/Gasket Removal, Inspection

Replacement and Reinstallation

Installation of Inner Door with Gasket

Step 7.

Clean any residual gasket residue or other debris

 

 

from combustion chamber surface before

 

 

installing the inner door/gasket assembly.

Step 8.

into position first.

 

 

channel of the inner

 

 

 

 

the 1/4” hex

 

 

 

 

left side inner

 

 

SCREWS.

Step 9.

tube and Piezo wire

 

 

 

 

gasket.

 

 

 

 

RADIUSED

 

 

.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

! WARNING

Stripped fastener connections may allow for seal breach of inner door. A seal breach may result in a fire or explosion causing property damage, personal injury or death. Do not over tighten screws in steps 8, 10 and 11.

If a fastener connection is stripped, contact the manufacturer listed on the water heater rating plate.

Radiused Channel for Feedline

Position thermocouple,

pilot tube and Piezo wire

 

6

SERVICE PROCEDURE RG-I

Inner Door/Gasket Removal, Inspection

Replacement and Reinstallation

Step 10. Firmly place right side inner door flange against the left side inner door flange and secure with two 1/4” drive screws from step 3c. DO NOT OVER TIGHTEN SCREWS.

Step 11. Align right side inner door to combustion chamber and verify the fastener holes of the combustion chamber are aligned with the right side inner door slotted opening. Verify seal integrity around combustion chamber opening. Secure right side inner door using 1/4” hex drive screws from step 3b.

DO NOT OVER TIGHTEN SCREWS. Verify both left and right sides of the inner door are properly positioned and sealed against the combustion chamber.

Verify threaded hole alignment with slotted openings in inner door

Secure flange with 1/4" drive screws

Step 12. Reconnect lead wires from combination thermostat/gas valve to in step 3). Note, wire terminations are interchangeable with either connections.

Step 13. Replace outer jacket burner access door.

Step 14. To resume operation follow the instructions located on the lighting instructions located in the installation and operation manual.

7

SERVICE PROCEDURE RG-II

Thermocouple Testing and Replacement

Closed Circuit Thermocouple Testing

Step 1. Disconnect thermocouple from combination thermostat/gas valve.

Step 2. Connect a thermocouple adapter (BWC P/N 239-44642-00,Robertshaw P/N 75036) at the thermocouple location in the combination thermostat/gas valve.

Step 3. Reconnect thermocouple to adapter. make certain all connections are tight (finger tight plus 1/4 turn)

Step 4. Using a multimeter capable of measuring millivolts, connect one alligator clip to the set screw of the adapter, and the other alligator clip to copper portion of the thermocouple.

Step 5. Following the lighting instruction label on the heater, proceed to light the pilot and allow to operate for three minutes. If the pilot will not stay lit, hold the red reset button (located on the combination thermostat/gas valve) down during this test.

Step 6. If meter reads 13 millivolts or higher, the thermocouple is OK. If reading is below13 millivolts replace the thermocouple.

Open Circuit Thermocouple Testing

Step 1. Disconnect thermocouple from combination thermostat/gas valve.

Step 2. Using a multimeter capable of measuring millivolts, connect one alligator clip to the end ball or contact portion of the thermocouple, and the other alligator clip to copper portion of the thermocouple.

Step 3. Following the lighting instruction label on the heater, proceed to light the pilot and allow to operate for three minutes. It will be necessary to hold the red reset button continuously

throughout this test. If meter reads 20 millivolts or higher, the thermocouple is OK. If reading is below20 millivolts, replace the thermocouple.

8

SERVICE PROCEDURE RG-II

Thermocouple Testing and Replacement

Thermocouple Replacement

Step 1. Turn off gas supply to water heater. Rotate knob of combination thermostat/gas valve to “OFF” position.

Step 2. Remove outer jacket door.

Step 3. Remove right side of inner door per SERVICE PROCEDURE RG-I,steps 3a through 3c.

Step 4. Disconnect thermocouple from combination thermostat/gas valve (3/8" wrench). Locate other end of thermocouple inside of combustion chamber and remove from pilot bracket. Pull firmly pulling away from the pilot assembly.

Step 5. Install new thermocouple into pilot bracket making certain thermocouple is fully engaged into the pilot bracket. Position thermocouple against left side inner door flange at its original position. Connect other end of thermocouple to combination thermostat/gas valve (finger tight + 1/4 turn).

Position thermocouple, in its original position

Make certain thermocouple is fully engaged into bracket

Step 6. Inspect inner door gasket per SERVICE PROCEDURE RG-I,Step 4.

Step 7. Install right side inner door per SERVICE PROCEDURE RG-I,Step 10 through Step 13.

Step 8. To resume operation follow the instructions located on the lighting instruction label or the lighting instructions located in the installation and operation manual.

9

SERVICE PROCEDURE RG-III

Pilot Assembly Inspection,

Cleaning and Replacement

Pilot/Electrode Assembly Inspection,

Cleaning and Replacement

Step 1. Turn off gas supply to water heater. Rotate knob of combination thermostat/gas valve to “OFF” position.

Step 2. Remove outer jacket door.

Step 3. Remove right side of inner door per SERVICE PROCEDURE RG-I,steps 3a through 3c.

Step 4. Disconnect thermocouple from combination thermostat/gas valve (3/8" wrench). Disconnect pilot tube from combination thermostat/gas valve (7/16" wrench). Disconnect feedline from combination thermostat/gas valve (3/4" wench).

Primary Air Step 5. Disconnect Piezo ignition wire from Piezo igniter. Opening

Step 6. Remove burner assembly from combustion chamber.

Step 7. Remove pilot/electrode assembly from feedline (1/4" drive tool).

Step 8. Inspect pilot for the following: (not required if replacing with new pilot)

a)Primary air openings for blockage. Must be free from any debris (dirt, lint, etc).

b)Kinks or cracks in the pilot tube. If found, the tubing must be replaced.

Step 9. Inspect pilot orifice: (not required if replacing with new pilot)

a)Remove 1/2" nut from bottom of pilot assembly.

b)Remove pilot tube and pilot orifice.

c)inspect pilot orifice for blockage, must be cleaned or replaced.

Step 10. Install pilot/electrode assembly to feedline, secure with screw from step 7.

Step 11. Re-Installburner assembly into combustion chamber, connect feedline, pilot tube and thermocouple to combination thermostat/gas valve.

Step 12. Install inner door per SERVICE PROCEDURE RG-I,step 4 through 13.

Step 13. To resume operation follow the instructions located on the lighting instruction label or the lighting instructions located in the installation and operation manual.

10