Furnace from hell (I need help)

[epic44]

I have a Keystone Cougar 30' travel trailer. The furnace is a Suburban SF30. Earlier this Spring it would not fire up. But it did so earlier in the season. I removed the furnace and replaced the Ignightor, Module Board and the Sail Switch. As long as I had it out I did not want to do it again. I was very careful in the removal and reinstallation. After all was done I tried it out. It worked perfect, fired right up, fans running and lots of hot air coming out of the registers. I celebrated, but I should not have. The next morning I decided to try it out again. Just to make sure. The fans came on, I could hear the click from the ignightor but no ingition, only room air temperature coming out. Why would it work 12 hours before but not the second time. All the replacement parts were new. The only thing left is the gas valve. But why did it work the night before. Other than that there is nothing else left to replace that did not work. It was the same thing as the original problem. Unbelieveable. Thought I had saved myself money by doing it myself. By the way no fuses blew before or after. No short. As a side comment the wires were joined with the smallest wire ties. To small for the wire sizes. Supprised it still held together pulling the trailer around. Your help would be greatly appreciated.

[Festus2]

epic44 -
1. It could be a problem with the propane ---- low level in tank or low gas pressure OR
2. Low battery voltage OR
3. defective or malfunctioning thermostat OR
4. Clogged main burner jet OR
5. defective limit switch OR
6. none of the above .... sorry, but ran out of ideas

When, not if, you find out what the problem is, let us know for future reference for others. Thanks and good luck...

[epic44]

The red flag is showing about 3/4 with a tank 80 % full. Stove works. Replaced everything else how about the furnace gas valve? Very confusing. The fans run unit tries to start x3 then goes in the shutdown mode. If the pressure regulator is bad why does the water heater and stove work

[labs4life]

My furnace displayed the same symptoms. Turned out to be the furnace brain. Replaced it under warranty and back in business.
Mine did EXACTLY as u describe yours doing.

[hankaye]

epic44, Howdy;

What temp. is the thermostat set to ??? It
was cooler back in the Spring wasn't it?

Had to ask.

hankaye

[LM3929]

I had the same problem and found that the inside of the propane pipe just before the metering jet was corroding and the flakes were plugging the jet.

I took the piece of pipe out and used a rust preventer in the pipe and never had a problem after that.

Lorne M.

[Roller4Tan]

On my changeover valve if it shows red the tank that the lever points to is empty. If the valve on the other tank is open then gas should come from that tank. I then switch the lever to the other tank and fill the empty one. Make sure you open the tank valves very slowly. Anyway, your picture shows the tank is empty.

[epic44]

Originally Posted by hankaye

epic44, Howdy;

What temp. is the thermostat set to ??? It
was cooler back in the Spring wasn't it?

Had to ask.

hankaye

Somewhat summer in NY I had to raise the set point up to 85 when it tried to start. The hand held remote does not show anymore the ambient temperature only the desired temp

[epic44]

When I reassembled the furnace apparently I did not position the igniter accurately. Took it apart and located it exactly per the I instructions. Works great. It must be exact or the spark will not ignite the gas.