Atmospheric Gas Water Heaters SERVICE MANUAL Troubleshooting Guide and Instructions for Service (To be performed ONLY by qualified service providers) Models Covered by This Manual : GX225S*BN GX155S*BN 25X78B*N 55X80B*N M1XR65T*(BN,CX) MI75S*(BN,CX) M2XR75S*(BN,CX) MI100T*(BN,CX) 65T65*(BN,CX) 75T80*(BN,CX) (*) Denotes Warranty Year Manual 238-46647-00A Save this manual for future reference
Table of Contents Page Service Procedure Trouble shooting Chart 3 --- Thermocouple Testing and Replacement 4 AG-I Pilot Assembly Inspection Cleaning and Replacement 5 AG-II Combination Thermostat/Gas Valve Testing and Replacement 6 AG-III Burner Operation Inspection, Adjustment, Cleaning and Replacement 10 AG-IV Dip Tube and Anode Inspection and Replacement 13 AG-V Page 2 2
Troubleshooting Chart SYMPTOM 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.) Not enough hot water PROBABLE CAUSE CORRECTIVE ACTION 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.
SERVICE PROCEDURE AG-I 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.
SERVICE PROCEDURE AG-II Pilot Assembly Inspection, Cleaning and Replacement R PILOT ASSEMBLY INSPECTION, CLEANING AND REPLACEMENT For White Rodgers Control, depress knob slightly and rotate clockwise to the “OFF” position. 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. Slide open inner combustion chamber door.
SERVICE PROCEDURE AG-III 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.
SERVICE PROCEDURE AG-III Combination Thermostat/Gas Valve Testing and Replacement THERMOCOUPLE TESTING See SERVICE PROCEDURE AG-I 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 minutes. If the pilot will not stay lit, hold the pilot button (located on the combination thermostat/gas valve) down during this test Step 2.
SERVICE PROCEDURE AG-III 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.
SERVICE PROCEDURE AG-III 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.
SERVICE PROCEDURE AG-IV Burner Operation Inspection, Adjustment Cleaning and Replacement R 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.
SERVICE PROCEDURE AG-IV Burner Operation Inspection, Adjustment Cleaning and Replacement MAIN BURNER: Inspection, Adjustment, Cleaning and Replacement (cont.) Step 3. Fully inspect combustion chamber for debris or carbon build up. Step 4. Burner should operate as adjusted in step 2, if not, repeat procedure compensating air shutter position for proper burner operation with inner door closed. Step 5. It may be necessary to clean main burner or main burner orifice to achieve proper burner operation.
SERVICE PROCEDURE AG-IV Burner Operation Inspection, Adjustment Cleaning and Replacement BURNER CLEANING (Cont.) Step 5. Disconnect (unscrew) Main burner (stamped steel burner) from main burner orifice or on cast iron burners, 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. Inspect pilot assembly per service procedure AG-II. Step 8.
SERVICE PROCEDURE AG-V Dip Tube and Anode Inspection and Replacement R DIP TUBE INSPECTION AND REPLACEMENT WARNING Heater components and stored water may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury. Step 1. 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.
SERVICE PROCEDURE AG-V Dip Tube and Anode Inspection and Replacement ANODE INSPECTION AND REPLACEMENT WARNING Heater components and stored water may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury. Step 1. Turn off water 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.
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