Product Alert Regarding GSW Water Heaters Using SIT Model 650 AC4 Gas Control

Attached is a Product Alert issued by GSW concerning certain of their Natural Gas and Propane Gas water heaters using an SIT Model 650 AC4 gas control. In some circumstances, during an initial start-up, main burner gas may flow while the control knob is in the pilot position. The problem is most prevalent if the unit has been stored or is being installed in a cold environment.

The alert provides additional instructions for the initial start-up of the heaters and information for determining the need for replacement.

GSW and SIT have worked to contain the problem encountered with the control and water heaters with a serial number beyond 0301263882 are not affected.

Water Heater Gas Control

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Product Alert



Subject:Temperature calibration of SIT GAS CONTROL VALVE Model 650 AC4
GSW Part # 62635-(01,02,03,04,05,06,07,08,09)

Product Affected:GSW Natural Gas Water Heaters with SIT blue gas / temperature control knob and blue or black knob inserts produced before serial # 0301263882
GSW LPG Water Heaters with SIT red gas / temperature control knobs
produced before serial # 0301263882

Date:January 23, 2003

GSW has received some reports of ignition of the main burner on initial start-up under limited circumstances when the gas / temperature control knob is in the pilot position and the pilot button depressed. When the installer then attempts to light the pilot, the unexpected main burner ignition could result in a burn or cuts to the installer in reacting to the situation.

Flame Rollout at initial start-up: At initial start-up, the gas control valve may hold the main valve open in a call for heat and therefore while lighting the pilot, the main burner could unexpectedly ignite. This condition is more likely to occur if the unit has been stored or is being installed in cold conditions. If this condition is identified, the gas control valve should be replaced.

When installing a water heater with a SIT 650 AC4 gas control valve in the identified group the following instructions must be complied with:

·Follow the installation instructions described in the owner’s manual.
·Fill the water heater with water prior to lighting the pilot.
·Turn the gas / temperature control knob to the maximum setting, then slowly turn the knob back to the pilot position. Listen for the main valve to close – this would be a snapping or clicking sound.

If the unit has been stored or is being installed in a cold environment and main valve does not close before the knob is turned back to the pilot position, the gas control valve must be warmed up to a temperature above 0 °C or 32 °F. Once warmed up, repeat the procedure above. If the gas control valve still does not close (clicking sound), replace the valve.

·Before lighting the water heater, install a pressure tap fitting and connect a manometer to the outlet pressure test port. When the pilot button is depressed, no pressure should read on the outlet test port. If there is pressure at the outlet port, replace the gas control valve.

·If there is a service call for high water temperature or the temperature and pressure relief valve was opening, check the gas control valve using the above steps and inspect the temperature and pressure relief valve for proper function. If the temperature and pressure relief valve is functioning properly the gas control valve must be replaced.

All new shipments of water heaters with serial # 0301263882 or beyond have been inspected to address this condition. If you have any questions please contact GSW Water Heating at 1-800-447-6575 Ext. 2