Empire Heater Propane RH65, pilot wont stay lit

[Its.me.again]

Can anyone help with this?

We have an Empire RH65, propane, B-vent heater. We depress the off/pilot/on control knob and light the pilot. As soon as the pilot knob is released, the pilot flame goes out. The gas valve on this is heater is a Mertik Maxitrol GV31. The heater is between 5-10 years old.

OK- we replaced the thermocouple, the pilot flame is big and blue and covers the thermocouple end. Also, when we hold a small propane hand torch on the thermocouple end to pre-heat it, when we release the pilot knob, the pilot flame still goes out. The thermocouple is screwed in tight at the gas valve end

The vent safety switch wires (by the flue output), we can bypass and this makes no difference in pilot operation.

This heater did this before last month, I took the plastic cover off the valve body and turned an adjustment screw "out" on the top of the valve body. I dont know if this is some sort of spring tension control for an internal magnet. It is not the pilot flame adjustment screw as this is non-adjustable on LP valve and on the side of the valve body.

Well, we got the heater started after that. (Coincidence or not?) Now the heater is off because we had to change propane bottle and cant restart the heater, pilot flame goes out when knob released. The heater ran fine last winter but started to develop these pilot flame issues at the end of last season.

BOTTOM LINE QUESTION....is there a "magnet" in the valve body that goes bad (becomes saturated-whatever that means) and wont work anymore? Do we need a new valve body? What does the adjustment screw I turned really do? So confused. Dont understand gas valves at all but guess its time to learn. Replacing the valve is a can do, but really dont want to if it is really another minor issue.

Thanks.

[jadnashua]

Futzing with gas when you don't know what you're doing can be quite dangerous for both your health and your property! A magnet doesn't go 'bad', but it might be possible it got corroded. The thermocouple generates a small electical current when it is heated. If the wires are shorted or open, it can't control the valve. Basically, it triggers the gas valve so it can work when it senses the pilot is lit. Not sure what you adjusted, but it was probably coincidence things worked after that. It may have been a gas/air adjustment, but that wouldn't affect the burner's ability to fire, only on how well it actually burned once on. Other than that, I've pretty much exhausted my knowledge on the subject. There may be another interlock somewhere - the manual should show them all.

[alternety]

I am not an expert. Some ideas that may help others to diagnose. Does the gas go through a pressure controller before it gets to the valve? If there is, perhaps that regulator is faulty. If there is not (or maybe if there is), there would likely be a regulator in the valve; which may have an external adjustment screw. Does the tank supply only this heater? If not, has any other attachment changed?