Propane Heater issues....please help

[capnkurt]

I agree with everyone saying your battery is gone. Just went through the same issues. If you let your battery get below 12.3 volts, you are doing damage to it. Mine got down to 10 volts while running the furnace one night and the fan would run but the igniter wouldn't work. It never recovered from that one low-voltage event. Yours getting down to 7-ish volts absolutely means it's finished.

Also, seems to me that's very strange behavior for your thermostat to be engaging your a/c (or the condenser fan) when it's in the heat position. It is a three-position switch, right? Even with low battery voltage this shouldn't be the case, so my guess is that the three-position thermostat switch is faulty. Also, if I'm not mistaken, I think that most/many thermostats run off low voltage, even those used in households. So, I'd replace the one in the van with an identical unit (if it turns out to be faulty) to guarantee that you get one that works with the systems in the van.

Capn

[86Scotty]

Unless the original was never compatible or wired wrong from SMB, or just wired to turn on the condensor/Danhard/Starcool/whatever on heat when it shouldn't come on at all. I had one in an RV do this once.

[JoeH]

Originally Posted by Glider

I
A final, somewhat on-topic note: wasps, mud daubers, and other friendly creatures love the Suburban furnace vents, as they are cozy, dry, warm places to nest. Make a habit of checking your vents when you do your walk-arounds, to ensure that they remain free of inhabitants. Some people install protective screens:
Mud Dauber Furnace Screen - $13.99

https://www.amazon.com/JCJ-M-300-fur.../dp/B00076WQBS

Good luck!

This was the source of all my issues with the Suburban.

[jkackley724]

I have a dumb question about battery monitors.
Will using the simple battery from Amazon (plugging it into my cigarette lighter) give me the voltage reading on my house battery (Deep AGM) or my car battery. I'm having problems with my furnace cycling. Basically my heater will come on just fine, heats up to thermostat setting and then shuts off and doesn't ever recycle or turn back on. I want to go ahead and rule out the battery issue. On a side note, in the morning, I turned the thermostat off and on a couple times to try and restart the heater, eventually it kicked back on and recycled several times before I eventually woke up to a warm van. Any thoughts/suggestions would be helpful.

[Flux]

Thermocouple?? Maybe an ailing ignitor??

I am assuming these use a peizo type ignitor. Furnace should shut off if no ignition or thermocouple senses no heat.

[MountainBikeRoamer]

The "heater limit switch" component went bad in my Suburban propane furnace and gave me similar symptoms to what you're experiencing, jkackley724.

Suburban Furnace Replacement Limit Switch
Manufacturer's Number: 230635
Suburban Furnace Replacement Limit Switch - $10.99



(By the way, this is a separate component from the thermocouple --- the thermocouple resides directly against the flame front, and shuts off the gas promptly if it senses that the flame has gone out.

By comparison --- the heater limit switch is designed to shut down the furnace if the overall furnace unit itself is running too hot. And its failsafe mode (if this component fails) is to shut the furnace down too. So if its gone bad....you get sketchy furnace behavior....)

For reference, the unsatisfactory heater behavior I observed:
The furnace would fire up (once!) and run just fine, happily heating up the van (to the thermostat setting....) but then after it had shut down...and the van had cooled down enough again to trigger the thermostat to fire up the heater again.....it just wouldn't fire a second time to heat the van. It would definitely keep trying (you'd hear the blower kick on, and the ignitor try several times and then give up....but the blower would keep running.....yet no flame, no heat.....)

Easy to swap in a new one of these heater limit switches, maybe worth a try.

EDIT: By the way, hat tip to forum member capnkurt for figuring this issue out with my heater!!!

[86Scotty]

To answer your battery monitor/cig lighter question: the dash ones are almost always on the starter battery since they come that way from the factory. Any additional ones SMB adds in the back are usually run off your house batteries. I’ve never seen a late model SMB without at least a couple in the back, always run off house batteries. Honestly, for the $5 or so these cost, get two and plug in to both (front and back) and get the readings. I bet they’ll be different with van off and match up when started when the alternator kicks power to both.


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[capnkurt]

Originally Posted by MountainBikeRoamer

The "heater limit switch" component went bad in my Suburban propane furnace and gave me similar symptoms to what you're experiencing, jkackley724.

Easy to swap in a new one of these heater limit switches, maybe worth a try.

EDIT: By the way, hat tip to forum member capnkurt for figuring this issue out with my heater!!!

Hey Mike, thanks for the props. I seem to remember, however that the limit switch itself wasn't the issue - correct me if I'm wrong: didn't we swap in the new switch only to find out that the symptoms were the same at first? Didn't we end up finding out that the wires that were hooked up to the switch had become oxidized/corroded enough that the resistance in them had built up enough to cause them not to be making sufficient contact and that was the ultimate issue? We ended up cleaning the contacts and then the furnace worked great, but we swapped out the switches anyway, since it didn't make any sense to put the old one back in.

capn