Bradford-White MI60T User Manual

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SERVICE PROCEDURE RG-IV

Piezo Igniter, Electrode Testing and Replacement

PIEZO IGNITER, ELECTRODE TESTING AND REPLACEMENT

With the pilot not in operation (no pilot flame) you can check the Piezo and electrode circuit by viewing pilot thru the sight glass located on the inner door and observing the spark action.

Step 1. Remove outer jacket door.

Step 2. Repeatedly depress the Piezo igniter while viewing the pilot thru the sight glass. If a spark is present, the circuit is OK. If there is no spark, proceed to step 3.

View spark Action through

Sight glass

Repeatedly

Depress Piezo

Igniter

Step 3 Remove orange wire from Piezo igniter and install a jumper wire in its place. Hold the other end of the jumper by the wire insulation or using an insulated tool, next to an unpainted surface such as the feedline or gas valve and depress the Piezo igniter. If there is a spark, the igniter is OK, the pilot is not functioning and must be replaced, see SERVICE PROCEDURE RG-IIIfor pilot replacement. If no spark is present the igniter is not functioning and must be replaced.

Step 4 With orange wire disconnected from piezo igniter. Using a common screw driver, place blade of screw driver under piezo bracket and gently pry bracket from front of combination thermostat/ gas valve and unhook bracket from rear of combination thermostat/gas valve.

Common Screw

Driver

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SERVICE PROCEDURE RG-V

Combination Thermostat/Gas Valve Testing

and Replacement

Combination Thermostat/Gas Valve Testing and Replacement

The combination thermostat/gas valve is a non repairable device. If trouble shooting has determined a problem with the combination thermostat/gas valve, it must be replaced.

If the burner and/or pilot do not function, service checks for gas pressure, thermocouple output, magnet assembly and ECO are to be performed. If these check OK, the combination thermostat/gas valve may be faulty.

LINE PRESSURE

The combination thermostat/gas valve is designed for a maximum line pressure of 14.0" w.c. and a minimum line pressure of 1.0"w.c. over the water heater rated manifold pressure. Line pressure must be checked with burner on and burner off to assure proper readings.

MANIFOLD PRESSURE TESTING (this procedure assumes a maximum line pressure of 14.0" w.c.)

Step 1. Set combination thermostat/gas valve to “OFF” position.

Step 2.

Remove pressure tap plug (3/16" Allen wrench) and install

 

 

pressure tap (7/16 wrench)

 

Step 3.

Connect manometer to pressure tap.

 

Step 4

Follow lighting instructions and proceed to light

Pressure Tap

 

main burner and observe manometer reading.

Shown Installed

Step 5

Proper operating range for natural gas is 4.0 ±0.3" W.C.

 

 

Proper operating range for L.P. gas is 10.0 ±0.5" W.C.

 

Step 6

If pressure is OK, set combination thermostat/gas valve to “OFF”

 

remove manometer and pressure tap and replace pressure tap plug. Check for gas leaks before placing water

 

heater back in operation. If pressure is out of the specification noted in step 5, proceed to step 7 or 8 for proper

 

service procedure.

 

Step 7

For White Rodgers control, the manifold pressure is not adjustable. If manifold pressure is outside the range

 

in step 5, the control must be replaced.

 

Step 8

For Robertshaw control, the manifold pressure is adjustable, proceed to step 9 for adjustment procedure

Step 9

While burner is in operation, remove regulator access cap to expose the regulator adjusting screw. With small

 

screw driver, rotate adjusting screw clockwise to increase pressure and counter clockwise to decrease pressure.

Step 10 Replace regulator access cap, set combination thermostat/gas valve to “OFF”. Remove manometer and pressure tap and replace pressure tap plug. Check for gas leaks before placing water heater back in operation.

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SERVICE PROCEDURE RG-V

Combination Thermostat/Gas Valve Testing

and Replacement

THERMOCOUPLE TESTING

See SERVICE PROCEDURE RG-II

MAGNET ASSEMBLY TESTING (White Rodgers Control)

Step 1. 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.

Probe top terminal on back of combination

thermostat/gas valve

Alligator clip to copper sheath of thermocouple

Step 6. With a meter reading of 13 millivolts or greater, rotate knob of combination thermostat/gas valve to the “OFF” position.

Step 7. The magnet should remain closed for a drop of at least 6 millivolts. You will here a “snap” or “click” sound when the magnet opens, if you hear this sound prior to a drop of 6 millivolts, the magnet is out of specification and the combination thermostat/gas valve should be replaced.

MAGNET ASSEMBLY 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.

Step 6. With a meter reading of 13 millivolts or greater, rotate knob of combination thermostat/gas valve to the “OFF” position.

Step 7. The magnet should remain closed for a drop of at least 6 millivolts. You will here a “snap” or “click” sound when the magnet opens, if you hear this sound prior to a drop of 6 millivolts, the magnet is out of specification and the combination thermostat/gas valve should be replaced.

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SERVICE PROCEDURE RG-V

Combination Thermostat/Gas Valve Testing

and Replacement

ECO (Energy Cut Off) TESTING

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

Step 2. Using a multimeter capable of measuring Ohms (or continuity), attach one lead (alligator clip) to the pilot tube. Insert the other lead (probe) fully into the magnet opening, Be sure the probe makes contact only at the top center of the magnet opening. Do not allow the probe to make contact with the threaded sides of the opening.

Step 3. If continuity is indicated, the ECO is OK. If continuity is not indicated, the ECO has opened and the combination thermostat/gas valve must be replaced.

COMBINATION THERMOSTAT/GAS VALVE REPLACEMENT

Step 1. Rotate knob of the combination thermostat/gas valve to the “OFF” position.

Step 2. Turn off gas supply to water heater.

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

Step 3. Disconnect gas supply line from combination thermostat/gas valve.

Step 4. Turn off water supply and drain water heater completely.

Step 5. Remove outer jacket burner access door.

Step 6. Right side inner door removal.

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

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

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 right side inner door and set aside. Be careful not to damage gasket material on inner door.

Remove

Resettable Thermal Switch

Wire Tie

Wire Connection

 

¼" Hex Drive Screws shown on

 

Right Side Inner Door.

 

¼" Hex Drive Screws at

 

Flange section of Inner Door

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SERVICE PROCEDURE RG-V

Combination Thermostat/Gas Valve Testing

and Replacement

Step 7. Removal of combination thermostat/gas valve.

a)Disconnect main burner feedline (¾” wrench), pilot tube (7/16" wrench) and thermocouple (3/8" wrench) from combination thermostat/gas valve & remove burner from combustion chamber.

NOTE: Feed line nut for natural gas control uses right hand threads,

LP control uses left hand thread.

b)Remove piezo bracket with piezo igniter (refer to SERVICE PROCEDURE RG-IV)from Combination Thermostat/Gas Valve.

c) Remove Combination Thermostat/Gas Valve from heater,

 

Wrench Boss

rotating counter clockwise using a control body wrench or a

 

 

 

length of ½" NPT pipe threaded into inlet of control.

 

 

To remove or install control, insert only ½" NPT threaded pipe into inlet and use to loosen or tighten control.

Step 8. Installation of Combination Thermostat/Gas Valve.

a)Install new combination thermostat/gas Valve using a control body wrench or a length of ½" NPT pipe threaded into inlet of control. DO NOT OVER TIGHTEN. Use caution not to damage cast

aluminum body of combination thermostat/gas valve. Be certain not to damage the bundled wire leads. Note: Combination thermostat/gas Valve must be installed in proper upright position to

assure the feedline will align properly at the inner door flange.

DO NOT OVER TIGHTEN. If control is turned past proper alignment, do not reverse direction to align.

b)Reattach Piezo bracket with Piezo igniter to combination thermostat/gas valve.

c)Reattach main burner feedline, pilot tube and thermocouple to combination thermostat/gas valve.

NOTE: Feedline nut for natural gas control uses right hand threads,

LP control uses left hand thread.

d)Gather wire leads of combination thermostat/gas valve and Piezo igniter and secure along side of feedline using new wire tie provided.

e)Connect gas supply piping to inlet of control. Use back up wrench on wrench boss of control, never use back up wrench on body of control.

Step 9. Reinstallation of inner door assembly.

a) Prior to reinstallation of inner door, fully inspect inner door gasket for the following:

> Tears

> Gasket Adhesion to inner door

> Missing Material

> Other imperfections that will inhibit proper seal

> Cracks

> Material left on combustion chamber

> Dirt or debris

 

If the gasket is not effected by any of the above, gasket replacement will not be required. If replacement is required, replace using new gasket kit following the instructions provided with kit.

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SERVICE PROCEDURE RG-V

Combination Thermostat/Gas Valve Testing

and Replacement

Step 9. Reinstallation of inner door assembly. (cont.)

b)Clean any gasket residue or other debris from combustion chamber surface before installing the inner door/gasket assembly.

c)Position thermocouple, pilot tube and Piezo wire against left side inner door flange gasket. DO NOT ROUTE

THROUGH RADIUSED CHANNEL WITH FEEDLINE. Be sure that thermocouple and pilot tube are not in position to interfere with outer jacket burner access door when reinstalled.

WARNING

A seal breach may result in a fire or

explosion causing property damage,

personal injury or death.

Position thermocouple, pilot tube and Piezo wire.

d)Firmly place right side inner door flange against the left side inner door flange and secure with two ¼” hex drive screws from step 6c. DO NOT OVER TIGHTEN SCREWS.

e)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 openings. Verify seal integrity around combustion

opening. Secure right side inner door using 1/4” hex drive screws from step 6b. 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 10. Reconnect wire leads from combination thermostat/gas valve to resettable thermal switch (See photo in step 6). Note: wire terminations are interchangeable with either resettable thermal switch connection.

Step 11. Replace outer jacket burner access door.

Step 12. Reconnect gas supply to Combination Thermostat/Gas Valve.

Step 13. Resume water supply to water heater. Be sure tank is full of water.

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.

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SERVICE PROCEDURE RG-VI

Burner Operation Inspection, Adjustment

Cleaning and Replacement

MAIN BURNER: Inspection, Adjustment,

Cleaning and Replacement

At periodic intervals (not more then 6 months) a visual inspection should be made of the main burner for proper operation and to insure no debris accumulating.

Main burner should light smoothly from pilot and burn with a blue flame with a minimum of yellow tips.

Steel burner models have a self adjusting air mixture and do not have an adjustable air shutter. Cast iron burner can have the gas and air mixture properly proportioned by adjusting the air shutter on the mixer face of the main burner (see step 2 below).

Main burner must be free from any debris accumulation that may effect burner operation (see burner cleaning procedure on page 17).

CAST IRON BURNER ADJUSTMENT

DANGER

Under no circumstances shall flammable materials be used or stored in the vicinity of the water heater. With the inner door removed the Bradford White Defender Safety System will be inactivated. If flammable vapors are present, a fire or explosion may result causing property damage, personal injury or death.

Upon completion of the cast iron burner adjustment procedure, the inner door must be replaced per SERVICE PROCEDURE RG-1,steps 4 through 14 to reactivate Bradford White Defender Safety System.

WARNING

Inner door and burner components may be HOT when performing this operation. Take necessary precaution to prevent personal injury.

Step 1. With main burner in operation, remove right side inner door per service procedure I, steps 3b & 3c. Be sure to maintain wire connection to resettable thermal switch for this adjustment procedure.

Step 2. To adjust for proper burning, loosen the air shutter nut, rotate the shutter to close the opening in the burner, then slowly rotate the shutter until the yellow tips disappear and the flame becomes blue. Tighten the air shutter nut. Too much air will cause the flame to lift off the burner ports and create noisy burner operation. Too little air (yellow tips) will result in soot formation.

Place right side inner door into proper position to confirm proper burner flame pattern and correct air shutter adjustment. It may be necessary to allow the burner to operate for several minutes for burner flame to stabilize.

Air Shutter Nut

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SERVICE PROCEDURE RG-VI

Burner Operation Inspection, Adjustment

Cleaning and Replacement

MAIN BURNER: Inspection, Adjustment,

Cleaning and Replacement (cont.)

Step 3. Fully inspect inner gasket per SERVICE PROCEDURE RG-I,step 4. Replace gasket if required following SERVICE PROCEDURE I, steps 5 & 6.

Step 4. Be certain that thermocouple, pilot tube and piezo wire are routed by inner door flange as shown and Reinstall inner door per SERVICE PROCEDURE RG-I,step 10 and 11.

Position thermocouple, pilot tube and Piezo wire.

Step 5. Observe burner operation through sight glass of inner door. Burner should operate as adjusted in step 2, if not, repeat procedure compensating air shutter position for proper burner operation with inner door in place.

Step 6. It may be necessary to clean main burner or main burner orifice to achieve proper burner operation. If cleaning is required proceed to burner cleaning section in this procedure.

BURNER CLEANING (Steel & Cast Iron)

Step 1. Remove inner door assembly per SERVICE PROCEDURE RG-I,steps 1 through 3c.

Step 2. Disconnect main burner feed line (¾ wrench), pilot tube (7/16 wrench) and thermocouple (3/8) wrench from combination thermostat gas valve and remove burner assembly from combustion chamber.

NOTE: Feedline nut for natural gas control uses right hand threads,

LP control uses left hand thread.

Step 3. Thoroughly inspect burner surface area and burner ports and remove any loose debris accumulation.

Burner Surface Area

Burner Port Area

Step 4. On cast iron burners, inspect

Burner Venturi

for any debris build up inside Opening burner venturi. If found,

disconnect feedline from burner and remove debris build up.

Feedline

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SERVICE PROCEDURE RG-VI

Burner Operation Inspection, Adjustment

Cleaning and Replacement

BURNER CLEANING (Cont.)

Step 5. Disconnect (unscrew) Main burner (stamped steel “B” burner) from main burner orifice or on cast iron burners (“C” burner), loosen air shutter & disconnect (unscrew) feedline from burner.

Step 6. Remove main burner orifice from feed line (½” wrench on steel burner, 3/8" wrench on cast iron). Inspect and clean if necessary.

Step 7. Remove pilot assembly, refer to SERVICE PROCEDURE RG-IIIfor cleaning and inspection.

Step 8. Reassemble burner.

Step 9. Inspect combustion chamber area of heater prior to reinstallation of burner assembly. If cleaning is required, refer to SERVICE PROCEDURE RG-VIII.

Step 10. Reinstall burner assembly into combustion chamber, reconnect feedline, thermocouple and pilot tube to the combination thermostat/gas valve.

Step 11. Reinstall inner door per SERVICE PROCEDURE RG-I,steps 4 through 13.

Step 12. To resume operation, follow the instructions located on the lighting instruction label or the lighting instructions located in the installation and operation manual.

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SERVICE PROCEDURE RG-VII

Resetting Thermal Switch

Testing and Replacement

RESETTABLE THERMAL SWITCH CONTINUITY TESTING

Step 1. Remove outer jacket door.

Step 2. Disconnect wire leads from resettable thermal switch.

Step 3. Using a multimeter capable of measuring continuity (Ohms), place one probe of meter on one of the brass connection tabs of the resettable thermal switch, and the remaining probe on the other connection tab.

Step 4. If continuity is indicated, the switch is closed, allowing millivolt current to pass.

Step 5. If continuity is not indicated, the switch is open, possibly due to an over heating condition. The switch is designed to open at predetermined temperatures depending on model. An open switch can be reset by depressing the red colored button located at the center of the switch. The overheating condition must be determined prior to putting the heater back in service.

PROBABLE CAUSE FOR RESETTABLE THERMAL SWITCH ACTIVATION

 

PROBABLE CAUSE

 

CORRECTIVE ACTION

 

 

 

1.

Verify adequate combustion air supply is

 

 

 

 

 

 

 

available.

 

 

Insufficient combustion Air

2.

Clear jacket slot openings of any dirt, dust,

 

 

 

restrictions or other obstructions.

 

 

 

 

 

 

 

3. inspect flame arrestor plate and clean with

 

 

 

 

stiff brush and/or vacuum to remove scale

 

 

 

 

deposits and debris.

 

 

 

 

 

 

1. Weak switch or switch

1. Replace resettable thermal switch

 

 

out of calibration.

 

 

 

 

 

2. Verify switch color code and approximate

 

 

2. Incorrect switch.

 

temperature.

 

 

 

 

 

 

Resettable thermal switch color code reference.

 

Approximate switch

 

Color Code

activation temperature

 

 

(open)

 

 

 

 

Blue

240°

 

 

 

 

Yellow

270°

 

 

 

 

Red

290°

 

 

 

 

Flammable vapor incident 1. Replace water heater.

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