Rick: I think because you do not want to uproot yourself to take your unit to a dealer and the dealer says it cannot be tested without taking it in you are looking for ways to troubleshoot the problem yourself.
The tests you have performed indicate there is no problem with the high limit switch and thermostat (not high/low sensors)
To confirm you have propane to the heater propane valve you can first ensure there is no power going to the heater, ensure there is no open flame near the heater then carefully open the propane line going to the valve. You will hear/smell propane right away if you have propane there. Re-tighten the fitting and turn off the propane. Now check the solonoid. You can do this by removing the electrical connections to the solonoids and checking the continuity across the two connections. You should have a double solonoid if it is like my Suburban heater so check both of them. They should read infinite resistance. However even though they may read correctly that does not mean they are not sticking or that the control board is sending 12V to them to open them.
With the propane still off, re-connect the electrical connections to the propane valve coils (solonoids) and turn on the heater, when you do this the control board should send 12V to the solonoids to open the valve, you should be able to measure that at the coil, this voltage should not fluctuate but remain constant until the control board stops sending the 12V to the coils. The igniter should now be sparking also. After several seconds the board will sense no ignition and stop the igniter and stop sending 12V to the solonoids, if the propane were on it would shut it off at the propane valve. Turn off the heater as you cannot repeat this process for about 15 seconds or more because the control board will not open the valve or start the igniter for a time period so that any propane not ignited is purged. If you get the voltage at the coils and the system shuts off after a short period of time I think you can be fairly certain the control board is ok. (however the condition might be intermittent, so you cannot yet dismiss it entirely)
To confirm the propane valve is actually opening and allowing propane through you can turn the propane on and repeat the above process but use a butane lighter at the burner, if there is propane there and you can light it with the butane lighter and you have a good blue flame then it is a likely a problem with the igniter which may not be close enough to the flame to ignite it in the time limits of the control board.
The most likely problem is either the propane valve or the control board.
Here is a link to the operators manual on your model of heater:
http://www.dyersonline.com/downloadf...tfile_id/1984/
I hope this helps in some way to resolve your issue. There are things I would do that I would not necessarily recommend to others but I have worked on these heaters many times and am very careful.
Linear Mode
