A.O. Smith PCG6240T403NOV 100, GAHH 40 100 GAS Control VALVE/THERMOSTAT Removal / Replacement

GAS CONTROL VALVE/THERMOSTAT REMOVAL / REPLACEMENT

Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician.

Tools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdriver, a short length of 1/2” threaded Pipe.

Removing the Gas Control Valve/Thermostat:

1.Set the gas control valve/thermostat to its lowest setting by pressing the “COOLER” and “HOTTER” buttons together at the same time holding for 1 second. Then press the “COOLER” button to the lowest setting (Figure 112).

2.Turn gas control switch to the “OFF” position (located right side of the gas control valve/ thermostat) and turn off the gas supply to the unit (Figure 113).

3.Disconnect the electric connection by unplugging the transformer from the wall outlet (Figure 113).

4.Release water pressure by opening a nearby hot water faucet, let run until water is cool to touch. Turn off water supply to the water heater.

5.Remove the manifold cover/ outer door from the unit by depressing on the lower portion and pulling outward.

6.Connect a drain hose to the drain valve and run it to an adequate drain or to the exterior of the building. Open the water heater drain valve and allow the water to drain from the tank.

7.Unplug all the electrical connections from the bottom of the gas control valve/thermostat (Figure 114).

8.Using a 3/4” open end wrench or a crescent wrench remove the manifold tube from the gas control valve/thermostat (turning counterclockwise -natural gas). Grasp the manifold tube and push down slightly to free the manifold tube from the gas control valve/thermostat (Figure 114).

9.Using a phillips head screwdriver remove the transformer box from the front of the water heater by removing the one (1) screw at the top of the transformer box (save screw for reinstallation later) (Figure 115).

10.Disconnect the two (2) electrical flag connectors from the pressure switch, also disconnect the air pressure tubing. Using a phillips head screwdriver remove the pressure switch from the water heater’s front by removing the two (2) screws securing it (save screws for reinstallation later) (Figure 115).

Figure 112.

HOTTER COOLER

Electronic Control Display

Figure 113.

ON

OFF

ON/OFF

SWITCH

UNPLUGGED

Figure 114.

IMPORTANT:
WHEN BRUSHING ON AN		GAS CONTROL
APPROVED NONCORROSIVE
LEAK DETECTION SOLUTION,		VALVE/THERMOSTAT
DO NOT SPLASH SOLUTION
ONTO ELECTRICAL CON-
NECTIONS.
		PRESSURE
MANIFOLD TUBE		SWITCH/FAN,
		FV SENSOR
POWER SUPPLY	IGNITER/	CONNECTOR
TRANSFORMER	FLAME
CONNECTOR	SENSE	DISPLAY, ANODE
	CONNECTOR	ROD CONNECTOR

Figure 115.

PRESSURE

SWITCH

MANIFOLD

TUBE

SCREW AT

TRANSFORMER

BOX

50