Thermostat quits

[McAulif]

Our Coleman Mach Comfort RV thermostat works fine...until it doesn't. When I turn it on the furnace heats the View perfectly then shuts off. As the temperature cools the thermostat usually kicks the furnace back on but inevitably a cycle will occur in which the heat comes on for about thirty seconds and shuts off. It will not restart until I switch "off" the thermostat then back to "heat". The same pattern will then occur. Sometimes five or six cycles will work. Sometimes only one. I have replaced the thermostat with the exact model. Same thing happened! Any ideas? The nights are getting cold!

[DavidM]

I don't think the problem is the thermostat. The furnace comes on as called for by the thermostat, then something happens to shut it down: maybe the air flow is too low which causes a trip due to high temps, maybe the thermocouple isn't getting enough flame on it and trips out. Something like that. It takes a shut off to restart it. This is all guessing on my part.

Maybe if you took off the cover you can see where the thermocouple is and if it is positioned right. Or maybe dust has plugged up the air flow and with low flow it gets too hot. Something like that may be the problem.

David

[McAulif]

Grateful for your suggestion!

[creativepart]

Any time your furnace doesn't light within a prescribed amount of time the furnace will turn off. So, what will happen is, the thermostat or thermocouple will request heat, the fan will begin running and the furnace will attempt to light the propane burners. The fan will be running for this entire time. However, once the heater fails to light - as registered by the flame sensor in the gas flow - it will shut down as a safety measure.

This can be caused by low propane, some problem in the propane gas line, a problem with the gas igniter, or the flame sensing thermocouple. It has nothing to do with the thermostat.

[McAulif]

Took View for service. The problem with the "thermostat" was actually a micro crack in the furnace control panel! When cold, the printed circuits would work. With heat expansion the printed circuit was interrupted, thus the furnace would not come on! Gimme a break!! New panel came with three year warrantee. works well. The technician said this is an extremely common failure in RV furnaces past ten years or so! Aargh!

[1237dmctlc]

Originally Posted by McAulif

Took View for service. The problem with the "thermostat" was actually a micro crack in the furnace control panel! When cold, the printed circuits would work. With heat expansion the printed circuit was interrupted, thus the furnace would not come on! Gimme a break!! New panel came with three year warrantee. works well. The technician said this is an extremely common failure in RV furnaces past ten years or so! Aargh!

Anybody like to guess where that board is probably made? And just because it might be assembled in the good old USA that the parts were?

[nownzen]

Use Dinosaur control boards! They are made in the USA
https://www.dinosaurelectronics.com/Ignitor_boards.htm