Bradford-White M2XR504T User Manual

Size:
1.47 Mb
Download

The Bradford White

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) M430T*F(BN,CX) MI30S*F(BN, CX) M440T*F(BN, CX) MI303T*F(BN,CX) M4403S*F(BN,CX) MI40T*F(BN,CX) M4403T*F(BN,CX) MI403S*F(BN,CX) M450S*F(BN,CX)

MI404T*F(BN,CX) M4503*F(BN,CX) MI503*F(BN,CX) M460T*F(BN,CX) MI50L*F(BN,CX) M1XR403S*F(BN,CX) MI504S*F(BN,CX) M1XR504T*F(BN,CX) MI60T*F(BN,CX) M2XR504T*F(BN,CX)

M2C504T*F(BN,CX)

50T65F(BN,CX)

(*) Denotes Warranty Years.

Save this manual for future reference

Manual 44943C

FLAMMABLE VAPOR

IGNITION RESISTANT WATER HEATERS

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

- - -

3

INTRODUCTION

The Bradford White DEFENDER Safety System®

The Bradford White DEFENDER Safety System® 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 opening 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 the supplied gas and is efficiently combusted, producing very low NOx emissions.

In the case where 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 the burner, 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.

4

TROUBLESHOOTING CHART

Flammable Vapor Ignition Resistant Water Heaters

SYMPTOM

PROBABLE CAUSE

Pilot Will Not Light

Pilot Will Not stay lit

when button is released

Pilot will light but the main burner will not come on

Pilot goes out periodically (after heating cycles, once a day, once a week etc.)

1.No incoming gas or too low gas pressure.

2.Gas control knob set to wrong position.

3.Pilot light button not being fully depressed when attempting to light pilot.

4.Pilot orifice or pilot tube is obstructed or kinked.

5.Pilot electrode not sparking to pilot.

6.Piezo igniter not functioning.

1.Poor thermocouple connection at combination thermostat/gas valve.

2.Thermocouple not fully engaged in pilot assembly bracket.

3.Pilot flame is not fully enveloping the thermocouple “hot” junction.

4.Weak or defective thermocouple.

5.Open ECO on combination thermostat/ gas valve.

6.Defective magnet in combination thermostat/gas valve.

7 Resettable thermal switch has opened.

1.Combination thermostat/gas valve set too low for desired water temperature.

2.Combination thermostat/gas valve temperature is satisfied.

3.Insufficient gas supply or low gas pressure.

4.Combination thermostat/gas valve has wide differential or is out of calibration.

1.Insufficient combustion air supply.

2.Incorrect, clogged vent system/ vent terminal or location.

3.Inconsistent gas supply or gas pressure.

CORRECTIVE ACTION

SERVICE

PROCEDURE

1.

Turn on gas supply and/or check line

1.

See Service Procedure

 

pressure.

 

RG-V,Page 12.

2.

Review lighting instruction. Set

 

 

 

combination/thermostat

4.

See Service Procedure

 

gas valve to correct position.

 

RG-III,Page 10.

3.

Review lighting instruction. Fully depress

 

 

 

pilot lighting button.

5.

See Service Procedure

4.

Clean, repair or replace.

 

RG-III,Page 10.

5.

Verify correct electrode position. Replace

 

 

 

pilot assembly.

6.

See Service Procedure

6.

Replace Piezo igniter.

 

RG-IV,Page 11.

1.Check connection at combination thermostat/gas valve. Proper tightness should be finger tight plus ¼ turn.

2.Inspect thermocouple to ensure that it is fully engaged into pilot bracket.

3.

Adjust tip of thermocouple to be fully

4.

See Service Procedure

 

engulfed by pilot flame.

 

RG-II,Page 8

4.

Check thermocouple and replace if

 

 

 

necessary.

5.

See Service Procedure

5.

Check ECO continuity and replace

 

RG-V,Page 14

 

combination thermostat/gas valve if

 

 

 

necessary.

6.

See Service Procedure

6.

Check magnet operation and replace

 

RG-V,Page 13

 

combination thermostat/gas valve if

 

 

 

necessary.

 

 

7.Determine cause of switch activation. To reset, depress button on resettable thermal switch located on inner door.

1.Adjust temperature dial on combination thermostat/gas valve.

2.Check temperature dial setting on combination thermostat/gas valve.

3.Check gas supply and line pressure.

4.Check combination thermostat/gas valve for proper operation, replace if necessary.

1.Verify adequate combustion air is available to the unit. Check and clear Jacket slot openings of any dirt, dust, restrictions or other obstructions. Inspect flame arrestor plate and clean with stiff bristled brush and/or vacuum to remove any debris accumulation.

2.Check venting for proper sizing and proper operation

3.Check gas supply and line pressure.

2.See Installation & operation manual.

3.See Service Procedure RG-V,Page 12

4.See Service Procedure RG-V,Page 12

1.See Service Procedure RG-VIII,Page 22

3.See Service Procedure RG-V,Page 12

Not enough hot water

1.Combination thermostat/gas valve set too low for desired water temperature.

2.Cold inlet water temperature is very cold.

3.High demand periods.

4.Incorrectly sized water heater for application.

5.Combination thermostat/gas valve is out of calibration/not functioning.

6.Out of spec dip tube is diluting hot water with cold water.

1.Check dial on combination thermostat/gas valve.

2.Extremely cold water going into the heater will decrease the amount of hot water produced. It may be necessary to temper incoming water supply.

3.Adjust high demand usage.

4.Contact Plumbing professional.

5.Check combination thermostat/gas valve for proper operation, replace if necessary.

6.Inspect dip tube and replace if necessary.

5.See Service Procedure RG-V,Page 12

6.See Service Procedure RG-IX,Page 23

5

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.

For White Rodgers Control, depress knob slightly and rotate clockwise to the “OFF” position.

For Robertshaw Control, rotate knob clockwise to the “OFF” position.

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

¼" Hex Drive Screws

Right and Left Side Inner Door.

 

¼" Hex Drive Screws at

 

Flange Area of 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.

6

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. Place the left side inner door into position first. Firmly position the radiused channel of the inner door aroundthe feedline. Using the 1/4” hex drive screws from step 3d, secure left side inner door in place. DO NOT OVER TIGHTEN SCREWS.

Step 9 Position thermocouple, pilot tube and Piezo wire against left side inner door flange gasket.

DO NOT ROUTE THROUGH RADIUSED CHANNEL WITH FEEDLINE.

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.

Position thermocouple, pilot tube and piezo wire.

Radiused Channel

for Feedline

7

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 ¼” 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

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.

Secure flange with ¼" drive screws.

Verify threaded hole alignment with slotted openings in inner door.

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

Step 13. Replace outer jacket burner access door.

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

8

SERVICE PROCEDURE RG-II

Thermocouple Testing and Replacement

CLOSED CIRCUIT THERMOCOUPLE TESTING (White Rodgers Control)

Step 1. Closed circuit testing is the preferred method for testing thermocouple. Following the lighting instruction label on the heater, proceed to light the pilot and allow to operate for three minuets. If the pilot will not stay lit, hold the pilot button (located on the combination thermostat/gas valve) down during this test

Step 2. Using a multimeter capable of measuring millivolts, connect one lead

using an alligator clip to the copper sheath of the thermocouple, use the second lead of the multi meter to probe the top terminal located at the back of the combination thermostat/gas valve.

Step 3. If meter reads 10 millivolts or higher, the thermocouple is OK. If reading is below 10 millivolts, replace the thermocouple.

Probe top terminal on back of combination

thermostat/gas valve

Alligator clip to copper sheath of thermocouple

CLOSED CIRCUIT THERMOCOUPLE TESTING (Robertshaw Control)

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

Step 2. Connect a thermocouple adaptor

(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 adaptor. Make certain all connections are tight (finger tight plus ¼ turn)

Step 4 Using a multimeter capable of measuring millivolts, connect one alligator clip to the set screw of the adaptor, 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 minuets. 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 below 13 millivolts replace the thermocouple.

9

SERVICE PROCEDURE RG-II

Thermocouple Testing and Replacement

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 pilot button down continuously throughout this test.

A reading of 20 to 30 millivolts indicates good thermocouple output.

THERMOCOUPLE REPLACEMENT

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

For White Rodgers Control, depress knob slightly and rotate clockwise to the “OFF” position.

For Robertshaw Control, rotate knob clockwise to the “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 the 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 + ¼ turn).

Step 6. Inspect inner door gasket per

SERVICE PROCEDURE RG-I,Step 4.

Thermocouple position

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.

10

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.

For White Rodgers Control, depress knob slightly and rotate clockwise to the “OFF” position.

For Robertshaw Control, rotate knob clockwise to the “OFF” position.

Step 4 Disconnect thermocouple (3/8" wrench), pilot tube (7/16" wrench), and feedline (¾" wench) from combination thermostat/gas valve.

NOTE: Feedline nut for natural gas control

uses right hand threads, LP control uses left hand thread.

Step 5 Disconnect piezo ignition wire from piezo igniter.

Step 6. Remove burner assembly from combustion chamber.

Step 7. Remove pilot/electrode assembly from feedline (¼" drive tool)

Step 8. Inspect pilot for the following:

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,

Primary Air

 

the pilot must be replaced.

Opening

Step 9.

Inspect pilot orifice:

 

a)Remove ½" 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.

Feedline

Nut

Pilot Orifice

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.

11