Atmospheric Gas Water Heaters For Models Using White Rodgers, Robertshaw and Honeywell Gas Control 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,SX) MI75S*(BN,CX,SX) M2XR75S*(BN,CX,SX) MI100T*(BN,CX,SX) 65T65*(BN,CX,SX) 75T80*(BN,CX,SX) C(S,D)W275T*(BN,CX,SX) (*) Denotes Warranty Years (GX155S6BN Model Shown) Manual 238-46647-00B Save this manual
Table of Contents Page 3 Service Procedure --- Troubleshooting Chart Honeywell Gas Control 4 --- Thermocouple Testing and Replacement White Rodgers and Robertshaw Gas Control 6 AG-I Thermopile Testing and Replacement Honeywell Gas Control 7 AG-I Pilot Assembly Inspection Cleaning and Replacement White Rodgers and Robertshaw Gas Control 9 AG-II Pilot Assembly Inspection Cleaning and Replacement Honeywell Gas Control 10 AG-II Gas Control Testing and Replacement White Rodgers and Robertshaw 1
Troubleshooting Chart For Models Using White Rodgers or Robertshaw Thermostat 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.
Troubleshooting Chart For Models Using Honeywell Gas Control Observe LED indicator on gas control. Error flash codes are displayed with a three second pause before repeating. Check and repair the system as noted in the troubleshooting table below: LED Status Not on and/or not flashing Control Status LED Indicator Probable Cause Pilot flame may not be present. Pilot flame is not present. Service Procedure 1.
Troubleshooting Chart (cont.) For Models Using Honeywell Gas Control LED Status Five flashes and a three second pause. Seven flashes and a three second pause. Control Status Probable Cause Service Procedure Thermowell fault 1. Damage to thermowell wires. 2. Thermowell sensor resistance out of range. See Service Procedure AG-III, Page 16 Gas control fault detected. 1. Gas control needs to be reset. 2. Gas control is wet or physically damaged.
SERVICE PROCEDURE AG-I Thermocouple Testing and Replacement For Models Using White Rodgers or Robertshaw Gas Control OPEN CIRCUIT THERMOCOUPLE TESTING Step 1. Disconnect thermocouple from gas control. 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. Figure 1 Step 3.
SERVICE PROCEDURE AG-I Thermocouple Testing and Replacement For Models Using Honeywell Gas Control OPEN CIRCUIT THERMOPILE TESTING Step 1. Disconnect red and white thermopile wires from the wire harness leading to the gas control. Step 2. Using a multimeter capable of reading millivolts, check across thermopile leads. Step 3.
SERVICE PROCEDURE AG-I Thermopile Testing and Replacement For Models Using Honeywell Gas Control THERMOPILE REPLACEMENT Step 1. Turn off the gas supply to the water heater by rotating the gas control knob to the “OFF” position (see Figure 7). Step 2. Remove outer jacket door. Step 3. Remove or slide open the inner combustion chamber door. Step 4. Disconnect red and white thermopile wires from the wire harness leading to the gas control. Step 5.
SERVICE PROCEDURE AG-II Pilot Assembly Inspection, Cleaning and Replacement For Models Using White Rodgers or Robertshaw Gas Control R For White Rodgers gas control, depress knob slightly and rotate clockwise to the “OFF” position. PILOT ASSEMBLY INSPECTION, CLEANING AND REPLACEMENT Figure 8 Step 1. Turn off gas supply to water heater. Rotate knob of gas control to “OFF” position. Step 2. Remove outer jacket door. Step 3. Slide open inner combustion chamber door. Step 4.
SERVICE PROCEDURE AG-II Pilot Assembly Inspection, Cleaning and Replacement For Models Using Honeywell Gas Control R PILOT ASSEMBLY INSPECTION, CLEANING AND REPLACEMENT Step 1. Turn off the gas supply to the water Heater. Rotate gas control knob to the “OFF” position. Primary Air Opening Step 2. Remove outer jacket door. Step 3. Remove burner assembly per Service Procedure AG-IV page 20. Figure 12 Step 4. Remove the pilot assembly from the burner assembly. Step 5.
SERVICE PROCEDURE AG-II Pilot Assembly Inspection, Cleaning and Replacement For Models Using Honeywell Gas Control R IGNITER/ELECTRODE TESTING AND REPLACEMENT With the pilot not in operation (no pilot flame) the igniter and electrode circuit function can be observed by opening the combustion chamber door and viewing whether there is a sparking action. Step 1. Make sure the gas control is in the “OFF” position. Step 2. Remove outer jacket door. Repeatedly Depress Igniter Step 3.
SERVICE PROCEDURE AG-III Gas Control Testing and Replacement For Models using White Rodgers or Robertshaw Gas Control Gas Control Testing and Replacement The gas control is a non repairable device. If trouble shooting has determined a problem with the gas control, 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 gas control may be faulty.
SERVICE PROCEDURE AG-III Gas Control Testing and Replacement For Models using White Rodgers or Robertshaw Gas Control THERMOCOUPLE TESTING See SERVICE PROCEDURE AG-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 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 Gas Control Testing and Replacement For Models using White Rodgers or Robertshaw Gas Control ECO (Energy Cut Off) TESTING Step 1. Disconnect thermocouple from gas control. 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 Gas Control Testing and Replacement For Models using White Rodgers or Robertshaw Gas Control Step 7. Removal of gas control. a) Disconnect main burner feedline, pilot tube and thermocouple from gas control & 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-III Honeywell Thermowell Testing and Replacemet HONEYWELL THERMOWELL TESTING Step 1. If gas control has gone into lockout due to excessive tank temperature (four flashes and a three second pause) reset the gas control to the “OFF” position. Then follow the instructions located on the lighting instruction label or the lighting instructions located in the installation and operation manual. Step 2. Observe the water heater operation.
SERVICE PROCEDURE AG-III Honeywell Thermowell Testing and Replacement DETERMINE WATER HEATER TANK TEMPERATURE NOTE: It is important to understand once the resistance for the thermowell is determined, water flow through the water heater should not occur. Prior to performing the steps below turn off cold water supply to the water heater. This will prevent cold water flow into the tank affecting the resistance value of the thermowell.
SERVICE PROCEDURE AG-III Honeywell Gas Control and Thermowell Replacement HONEYWELL GAS CONTROL & THERMOWELL REMOVAL Gas Control Thermowell Step 1. Turn the gas control knob to the “OFF” position. Step 2. Turn off water supply and drain water heater completely. Step 3. Turn off and disconnect gas supply to control Step 4. Disconnect wire harness and burner assembly from the gas control. Figure 31 Step 5. Remove gas control and thermowell by rotating flats of the thermowell counter clockwise.
SERVICE PROCEDURE AG-III Honeywell Gas Control and Thermowell Replacement HONEYWELL GAS CONTROL ASSEMBLY TO THERMALWELL Step 1. Install threaded end of thermowell into water heater. When tight, be sure thermowell flange is positioned so that thermowell relief opening is in the 6 o’clock position for proper control alignment (see Figure 35). Thermowell flange slots Route wire through relief opening 6 o’clock position Figure 35 Step 2. Route lead wires through the relief opening (see Figure 35). Step 3.
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. Be certain that thermocouple or thermopile, and pilot tube are routed correctly through the relief opening in the combustion chamber. Position thermocouple or thermopile, and pilot tube. Step 5.
SERVICE PROCEDURE AG-IV Burner Operation Inspection, Adjustment Cleaning and Replacement BURNER CLEANING (Cont.) Step 5. Steel Burner: Disconnect (unscrew) burner from main burner orifice. Cast Iron Burner: Disconnect (unscrew) main burner feedline from burner. Figure 44 Step 6. Remove main burner orifice from feedline. Inspect and clean if necessary. Step 7. Inspect pilot assembly per service procedure AG-II. Step 8. Reassemble burner assembly. Step 9.
SERVICE PROCEDURE AG-V Diptube and Anode Inspection and Replacement R DIPTUBE INSPECTION AND REPLACEMENT WARNING Water 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 the gas control knob to the “OFF” position. For White Rodgers Control, depress knob slightly and rotate clockwise to the “OFF” position.
SERVICE PROCEDURE AG-V Diptube and Anode Inspection and Replacement ANODE INSPECTION AND REPLACEMENT WARNING Water 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 gas control knob to “OFF” position. For White Rodgers Control, depress knob slightly and rotate clockwise to the “OFF” position. For Honeywell gas control, rotate knob counter clockwise to the “OFF” position.
