What's with the furnace level switch?

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

ImmortalSoFar

Member
Joined
Jan 22, 2006
Posts
8
I'm parking on people's yards at the moment (not the most level areas) and the furnace has an external switch which keeps turning off. It's labelled "No hand hold" and I'm guessing it's triggered by being on uneven ground. When it pops out, the furnace stops working instantly and pushing it back in gets her going for another 5 minutes or so.

After a freezing night here in Western Washington and numerous trips out into the rain, I finally used some electrical tape to shut the damned thing up. Is this a nannying safety feature or is there a valid reason for it to be there? I'm about to run a bypass on the switch - is there anything I need to know?

Thanks,

Mike.
 

Jim Dick

Moderator Emeritus
Joined
Feb 11, 2005
Posts
7,651
Location
Titusville, FL
Mike,

That "switch" sounds like a circuit breaker. It pops when too much current is drawn. I'd have someone look at it soon as taping it closed could cause overheating and might lead to a fire.
 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
74,969
Location
At my Silver Springs FL home
I've never heard of such a switch, nor is there any reason a furnace could be sensitive to level ground.  And labeling it "No Hand Hold" is not helpful at all!  Very strange!  Where is this switch located, i.e. is it near the furnace vent or somewhere else on the exterior.  And what make/model furnace do you have (usually Atwood or Suburban).

I notice you said "Pops out" to describe the action of the switch. Did you mean just that, that it is a button that pops out and you reset it by pushing it back in? Or is the action more like the typical circuit breaker or wall switch, flipping up/down or sideways?

I too am wondering if it is some sort of 12V circuit breaker. Do other 12v powered things work when the switch  is tripped? Interior 12v lights, for example?  Or it might be a thermal overload of some kind, tripping if the exhaust heat gets too high? I suppose it could even be a sensor that attempts to verify that there is plenty of airflow in/out through the furnace vent system, which is necessary to prevent carbon-monoxide inside the RV.
Anyway, it is definitely something to be checked out, since it is obviously intended to be a safety interlock of some kind.
 

ImmortalSoFar

Member
Joined
Jan 22, 2006
Posts
8
I managed to track down an online circuit diagram and it seems to be a 5amp circuit breaker. I've taped it and recognize the symptoms when it's struggling so that I can give it a break (at least I don't have to go out into the rain to reset the damned thing).

Any idea why it would draw too much current? A short circuit maybe? As soon as I've fixed the hundred or so other things that need fixing (eg a leaking roof!) I'll try and track down the cause and any hints about where to start would be much appreciated.

Mike.
 

Carl L

Moderator Emeritus
Joined
Mar 14, 2005
Posts
7,239
Location
west Los Angeles
Any idea why it would draw too much current? A short circuit maybe? As soon as I've fixed the hundred or so other things that need fixing (eg a leaking roof!) I'll try and track down the cause and any hints about where to start would be much appreciated.

A breaker tripping is a sign of overload or short circuit.? ? If the thing is controlling a single piece of equipment, like a furnance, it is probably a short.? ?It could also be a defective breaker but that ain't the way to bet.

I would treat it as an urgent item.? Get it checked now.? ?By a pro.
 

Scoundrel

Well-known member
Joined
Jan 6, 2006
Posts
106
Location
Corona, California
ImmortalSoFar said:
I managed to track down an online circuit diagram and it seems to be a 5amp circuit breaker. I've taped it and recognize the symptoms when it's struggling so that I can give it a break (at least I don't have to go out into the rain to reset the damned thing).

Any idea why it would draw too much current? A short circuit maybe? As soon as I've fixed the hundred or so other things that need fixing (eg a leaking roof!) I'll try and track down the cause and any hints about where to start would be much appreciated.

Mike.

You will have allot more then a few hundred other thing to fix if the circuit breaker overheats and causes a fire. That should be number 1 on your list.....
 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
74,969
Location
At my Silver Springs FL home
I managed to track down an online circuit diagram and it seems to be a 5amp circuit breaker.

5 amps is barely adequate for a furnace fan - the usual RV furnace fan routinely draws 5 amps. What brand & model furnace is it?  You can then check the furnace specs for the standard amp draw and fusing requirements.

Is this breaker is a fuse panel along with other breakers and fuses?  They make breakers that plug in like fuses and I'm thinking that somebody got tired of replacing fuses and stuck a breaker into the fuse slot. If so, it may be that they simply used one too small for the normal furnace load.  But don't change to a higher amp breaker without first verifying that the furnace is indeed designed to draw 5 or more amps.
 

2006F350

Well-known member
Joined
Dec 6, 2005
Posts
393
Location
Memphis TN
In talking with an electrician friend, I was told that everytime a circuit breaker trips, it becomes weaker and less current draw will trip it the next time. Don't know if this same scenerio is applicable to RV's, but since they work on the same principle as a home breaker, I would tend to think so. Mine was a 15A breaker in my home, and after it had tripped a half dozen times, my friend put an inline meter on it, and we loaded down the circuit, and found that it was tripping around 12A. Replaced it with a new one (same size of course), and it's not tripped since. You may consider replacing the circuit breaker before letting the dealer get rich just to tell you the breaker was bad, regardless, you need to get it done before it goes from a $20 breaker to a multi-thousand dollar RV replacement.

Larry
 

ImmortalSoFar

Member
Joined
Jan 22, 2006
Posts
8
Thanks Larry,
it was the breaker switch. I initially tried a fuse to see if that would narrow it down but, as I later discovered on a multimeter, the initial surge when it starts blew it right away. The "official" replacement was $40 but volts is volts and amps is amps so I got a $7 version from KensElectronics.com and it works great!

Finally the luxury of a heater that can keep the RV warm all night!

Thanks everyone for your help.

Mike.
 
Top Bottom