Furnace

[dcarver]

My furnace keeps turning off after running at the set temp for an extended period of time. For example: I set the thermostat at 68 when we go to sleep at night. Wake up in the morning and it's 60 in the camper. I cannot get the furnace to turn back on unless I pull the fuse at the control panel. Then it kicks back on like there was no problem, however it will do the same thing later on. Any ideas?

[jflood1274]

Three possible problems
Thermostat - Remove from wall, disconnect wires, and "nut" them together. If furnace runs without shutting off, you've found your problem. Easy to replace.
High Limit Switch - Shuts furnace off when output air reaches an "unsafe" high temp. Also fairly easy and inexpensive fix.
Sail Switch - Monitors air flow across burner; shuts off furnace if inadequate. Inexpensive part but may be difficult to access depending upon your unit.
You may want to be sure that output ducting is clear / not crimped or crushed, and that all registers are fully open.
I have also seen intake or exhaust air access partially blocked due to insect infestation (nesting, etc). This is checked from outside your coach. Good Luck

[Skip426]

As always, more info will get you better answers.

Could you add your furnace brand, age, and model number and your thermostat's info to your post.

[Gigattime]

Originally Posted by jflood1274

Three possible problems
Thermostat - Remove from wall, disconnect wires, and "nut" them together. If furnace runs without shutting off, you've found your problem. Easy to replace.
High Limit Switch - Shuts furnace off when output air reaches an "unsafe" high temp. Also fairly easy and inexpensive fix.
Sail Switch - Monitors air flow across burner; shuts off furnace if inadequate. Inexpensive part but may be difficult to access depending upon your unit.
You may want to be sure that output ducting is clear / not crimped or crushed, and that all registers are fully open.
I have also seen intake or exhaust air access partially blocked due to insect infestation (nesting, etc). This is checked from outside your coach. Good Luck

Great response, thorough answer. The experience on this forum is outstanding.

[Snappy2265]

One other possible problem may be LP regulator frosting up in below freezing weather, had that happen a couple of times, especially when tank is getting low, right before the auto switch is trying to switch tanks, some regulators have lower flow rate on secondary side if you don't manual switch the lever. Anyway some furnaces will shut down completely if the LP pressure is too low and doesn't ignite after the second try, then manually has to be reset by cycling completely off or disconnecting power to the unit

[dcarver]

If you need to know I have a suburban furnace that's 7 months old.

Anyway I check the exhaust outlet/inlets and they're clean. Have not check the sail switch. Connections are solid.

For the moment we're good. I thought maybe the flow wasn't enough from one bottle so I opened both because I have the auto switch over for my LP tanks. Bottles were just refilled last Tuesday so I'd be really surprised if we ran through one bottle in a week ( 3 days of which we weren't home).

I will holler back if it works or doesn't work. I'd be surprised if it does work all through the night but as I write this, the furnace kicked back on like it should.

[L.C.Gray]

To add to what snappy said, in really cold weather my furnace wouldn't run with just one bottle open, it had to have both open to keep up enough gas pressure/flow.

[dcarver]

Little update. Had an RV tech out today, he thinks it's the sail switch and will take it out, clean everything, and replace the switch. Funny thing we found out. If you cover the inlet air the furnace lights every time. He was baffled by this. I'm glad I found a bandaid until tomorrow. Was real feel of 7 this morning when I woke up and the trailer was 50 inside.

[dcarver]

So I'm stopping the blocking the air intake to light. Loud enough pop to scare the crap out of my wife inside. Gonna be a fun night...

[ModestMonk]

Originally Posted by dcarver

If you need to know I have a suburban furnace that's 7 months old.

Anyway I check the exhaust outlet/inlets and they're clean. Have not check the sail switch. Connections are solid.

For the moment we're good. I thought maybe the flow wasn't enough from one bottle so I opened both because I have the auto switch over for my LP tanks. Bottles were just refilled last Tuesday so I'd be really surprised if we ran through one bottle in a week ( 3 days of which we weren't home).

I will holler back if it works or doesn't work. I'd be surprised if it does work all through the night but as I write this, the furnace kicked back on like it should.

The problem with small tank/s feeding a large draw device in the winter comes to a head the colder it gets. Having just filled the tanks there was very little surface area and head room to allow the liquid propane to boil (-44*)and become a vapor. As the device depletes this vapor quickly it will take longer to boil off enough vapor as it was so cold out. Opening both tanks or adding another, and not "filling" the tank/s will help also, tanks shouldn't be filled beyond 80% so try 70%.

[wa8yxm]

My guess. Your converter is not keeping up with the load, the batteries are running down and after 3 attempts the furnace "locks out" (if you go out and look at the board there may be an LED blinking 3-3-3-3- on the board)

Pulling the fuse (or flipping the circuit breaker if so equipped, looks like an on/off switch) off and on resets it.

I stress that is a guess.

Guess #2

There are two different things that get put into propane tanks (Well several actually but two that count) Propane (naturally) and in some markets BUTANE gets put in in place of Propane,,, Now understand this is Fraud, and Illegal, and if you ever catch one and can prove it you are entitled to damages and they to prison but... Well, it happens, the risk is worth the profits at least some think so (i do not) because they can charge for PROPANE but Butane is less expensive and pocket the profit.

SO what is the difference TO YOU?

Propane has a vapor temp (It will turn to vapor) at temps in excess of 30 below Zero (Right close to 40 below in fact) But Butane remains liquid at most anything below the freezing point of water (32F 0C) so if it gets COLD Butane won't heat your house(RV) and again, The furnace tries 3 times and goes into LOCKOUT, but when you get up (After the sun gets up) in the AM, temps are a degree or two higher and all works.

[ModestMonk]

Originally Posted by wa8yxm

My guess. Your converter is not keeping up with the load, the batteries are running down and after 3 attempts the furnace "locks out" (if you go out and look at the board there may be an LED blinking 3-3-3-3- on the board)

Pulling the fuse (or flipping the circuit breaker if so equipped, looks like an on/off switch) off and on resets it.

I stress that is a guess.

Guess #2

There are two different things that get put into propane tanks (Well several actually but two that count) Propane (naturally) and in some markets BUTANE gets put in in place of Propane,,, Now understand this is Fraud, and Illegal, and if you ever catch one and can prove it you are entitled to damages and they to prison but... Well, it happens, the risk is worth the profits at least some think so (i do not) because they can charge for PROPANE but Butane is less expensive and pocket the profit.

SO what is the difference TO YOU?

Propane has a vapor temp (It will turn to vapor) at temps in excess of 30 below Zero (Right close to 40 below in fact) But Butane remains liquid at most anything below the freezing point of water (32F 0C) so if it gets COLD Butane won't heat your house(RV) and again, The furnace tries 3 times and goes into LOCKOUT, but when you get up (After the sun gets up) in the AM, temps are a degree or two higher and all works.

Thanks I hadn't heard that before. We've always had our tanks refilled by known local dealers. I have had trouble with known local dealers but not at this level of fraud. So the butane will hold the capstan also?

[dcarver]

I've heard of this butane thing before. I've found a place here that charges only 30$ for 60lbs of propane. Does that seem cheap? Other places were a little over double that.

[clifford j]

The going rate for propane in eastern PA is 2.11 per gallon. My 40 pounders are a little less than 20 bucks with tax.

CLIFFORD