Repairing Tankless Girard GSWH-1M

[edsamuel1957]

A couple of months ago we took our first trip with our 2013 Greyhawk. We bought it used a few month ago. Took it down to the coast and the temperatures where in the high 90's and low 100's. The first time I tried to use the hot water it started to oscillate hot and cold with it set to the lowest temperature. The pressure wasn't that great at the RV park, so I tried using the fresh water tank and pump. Got the same results. Long story short. This is what I had to do to fix it.

1. Replaced the ECO Thermostat sensor/switch with a 82c version. The orginal was 55c. Barely above the normal hot water temperature. (Didn't fix my problem, but the oscillations were longer intervals.
2. Replaced the LP gas modulation valve inside the water heater. The valve was sticking in the full on position.

For anyone having problems with theirs. Apparently this valve can go bad if it sits for a long time unused. The side of the valve which feeds the burner is exposed to the outside air. Over time humidity and and other contaminates can damage it.

The gas modulator is difficult to find. Had to order it from Girard.