SF-30F Suburban furnace (intermittent)

[We_ride___]

Guys - Heard the clicking but no furnace or fan coming on.
Thermostat set to 'Furnace or Off' makes no difference.

So I took out the furnace, took it out of its aluminum shell/sleeve - tested the sail switch (good continuity).

Blew out the gas lines with HP air.

Took off the circuit board while running it successfully during the bench test; no intermittent problems.

When I slide it back in to try it hooked up to the propane, it works fine - and comes on and off with the appropriate temp settings.

However when I go get the aluminum shall/sleeve, and slide the whole item back in, the original symptoms re-appear.

It just clicks, with no blower and no igniter. What am I missing?

Cheers,



Kyle

[opnspaces]

Since the sleeve is the limiting factor I wonder if it is an airflow problem. If you are testing on a bench, can you test with the sleeve only partially installed at different levels and see if it works? Maybe once you find the point that it stops working the problem may be more obvious.

Does the furnace work inside the sleeve, but with the sail switch unplugged and the wires jumpered together? Don't leave it like this, but it is a test I would probably try.

Also in the link I provided above there is a Suburban Technical Information link (fifth one down in the Furnace Service Manuals section) that describes each part of the system. In that manual they describe the 10 most common failures of the furnace.

[We_ride___]

Cheers - to confirm, it just not work when its IN the the sleeve. Outside the sleeve, it works fine.

I cannot see it grounding anywhere.

[opnspaces]

The way I read your two posts they contradict each other. Does it only work inside the sleeve or only work outside the sleeve. Have you tried the service manual to see if there are any possible hints? I believe BryantRV has that specific manual online.
Link

[We_ride___]

Hi thanks - the click I'm reporting is the not the igniter, but relay clicking on, and nothing is happening.

It just works inside the sleeve, and does not work outside the sleeve. Cant see it grounding anywhere.

My Father just reminded me, we have new manual thermostat in the wall, from about a month ago - but neither the new or old thermostats have worked 100% correct.
As in the Furnace/off/Cool switch has never worked properly, and that he only ever uses the temperature to control the on/off during the days and nights.

[garyemunson]

The 'click' sounds like the fan relay. You must not be talking about the clicking of the spark igniter because I do not think it comes on unless you get the sail switch made up which would not be happening if the blower is not running. You might want to see if the sleeve is tweaking something and interrupting the 12 volt feed to the fan. The sleeve should really be secured on the RV letting you easily pull the unit in and out of it. A lot of times the builders don't cut the hole in the RV big enough and just force everything in. In your case, maybe binding something? I had the small hole problem and had to do some "tin knocking" to get the sleeve back in shape although in my case it didn't affect the operation. Made the hole the proper size and put the sleeve back in. Now I can just pull a single screw on the bottom of the unit and slide it easily out of the permanently attached sleeve.

I used a trailer wire plug to make a quick disconnect for mine with extra wire to put it on a sawhorse next to the RV. There was already enough extra gas hose to reach

[opnspaces]

Is there a wire that shorts to ground when you slide the sleeve back on?