Repairs
Thermal Regulator
The thermal regulator is behind a screw off cap between the in/out pipes in the heaters header. With the pump off, unscrew the cap and pull the regulator out. Note, if the regulator does not come out easily and feels like it hung up on something, then the bypass is broken and hanging in the way. If it comes out with no issues I'm sure you find it's all gunked up. Then use you fingers and stick them in the opening and feel up around towards the top middle and you should feel a round button like item, that's the bypass. If you feel it and it seems to be solid, then you are good with that.[1]
To test the thermal regulator Put it in hot water (130 to 140 F) to see if it opens.
The thermal regulator is sensitive to water chemistry and can get erosion.
Bypass Valve
If the byass valve is broken the heater will short cycle and make noise
You will have to take the manifold off to replace the Internal by-pass kit P/N 77707-0001.
Guide to replacing the bypass valve
Bad Temperature Sensor
- Problem - Heat will not fire, blower does not even turn... heat is set at 89*. membrane is showing water temp 107... easy touch panel temp reading is accurate (thermometer in pool 83*).[2]
Blower not Operating
Listen closely when you turn the heater on, after it cycles through the 888, 128, R13. You may need to put your ear right next to the top of the heater (where the board is) to hear if the small relay on the board clicks (May sound more like a "tick" than a "click"), giving voltage to the blower. This click will be more subtle than the click you normally hear when the gas valve opens (you wont hear that one though if the blower never starts).[3]
If you can hear the click, look at the blower. No click, look at the board. If you are getting the AFS error, that means the safety switches have been satisfied, and the board should be telling the blower to start (power to relay coil).
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