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Lakeman1 · 07-23-2015, 08:54 AM

I have a 2004 Pace Arrow 37C. It is an early 2004, the first few they made were 30 amp coaches. My furnace will start running by itself, weather the switch is off or even if the AC is running! I happen to be in the bathroom once when it happen and heard a relay arcing in the electrical panel (on the 2004 30 amp units the panel is under the bathroom sink shelf). I tried once to remove the panel (different problem) but the wires were not long enough to allow it to be removed, so I gave up. I am hoping that I can get to it by removing the shelf above it. I have not had time to look at it yet. Anyone have any experience with this panel or problem? Thanking you in advance for any help.

Gary RVRoamer · 07-23-2015, 09:19 AM

The furnace has its own power, but it starts whenever it sees +12v on the signal wire from the thermostat. It conceivable that the furnace circuit board has a defect and just starts up anyway, but that's really rare. More likely it received a false "heating needed" signal and went through normal start-up.

In basic systems the signal comes direct from the thermostat, but newer RVs, especially those with heat pumps, often have a zone controller or integrated a/c+furnace controller and the signal to the furnace comes from that rather than direct from the t-stat. The zone control is usually located right at the a/c unit.

Lakeman1 · 07-23-2015, 09:54 AM

I have a the controller for the front and rear AC and heat, it also has the shed feature, it does not matter whether it is in the off position or AC, the furnace does its own thing, I can have thermostat on 50* and it can be 90* inside and the furnace will come on. My concern is the arcing relay, I think that is the problem but not sure how to get to it.

Roger Kneeland · 07-23-2015, 12:19 PM

I had a similar problem with my 2000 Pace Vision. I ended up removing the shed circuitry control box ( located under the frig in my unit) and found white "corrosion" ( not the right term) on the pc board. I carefully cleaned it up with toothbrush and control cleaner and that did the trick . I suspect that a small amount of water had run down from the frig over the years after shutting it down after returning from weekend trips.

Keep us posted as to what you find .

R

ga traveler · 07-23-2015, 01:50 PM

I have had this happen a couple of times with the intellitec system. You are correct that it is a relay on the intellitec board. These relays are problematic. We bought a couple of rebuilt boards and they all had new relays soldered in. If this is the problem, you should be able to hear the relay chattering when it happens. I came out one day and found both Air Conditioners running and both furnaces going full blast in a Pace Arrow. The thermostat was set on AC.You should be able to buy just the relay.

Roger Kneeland · 07-23-2015, 07:15 PM

That reminds me , that was exactly what pointed me to the controller ... A chattering relay !

R

Lakeman1 · 07-23-2015, 08:55 PM

[QUOTE=Roger Kneeland;2663414]That reminds me , that was exactly what pointed me to the controller ... A chattering relay !

Are you talking about a relay on the controller? What I have is not a chattering relay and not on the controller. I have an arcing relay in the electrical distribution panel. Thanks for your help.

Gary RVRoamer · 07-24-2015, 06:06 PM

I hear ya regarding the Intelletec controller, but how can that affect the furnace, which is strictly a 12v beast? The furnace only starts if +12v appears on its thermostat wire. It doesn't even know the temperature, and doesn't care (but you already know that!). If the signal line tells it to heat, it turns on and stays on until the signal goes away.

I'm wondering if maybe there is some stray 12v power jumping around instead of that arcing relay you suspect.

Roger Kneeland · 07-24-2015, 07:24 PM

Gary,

I had never explored the system before I had "issues" with the furnace . As it turns out they combine the "climate control" with the "energy management system " in the same PC board . It is actually all low voltage / current .... The inputs are from the total AC current sensor , the temp sensors , and temp controls . The outputs control the low voltage control of the air cond and furnaces.

R

mchero · 07-25-2015, 09:47 AM

We have to AC/Heat pumps as well as 2 gas furnaces. We have the RVComfort.zc. When set to heat the forward gas furnace will start up, run for about a second or two then turn off! I can hear a relay "click" at the thermastat when is goes on then a click when it goes off.
I don't know where to start on my issue.

Lakeman1 · 08-09-2015, 09:33 PM

I think I have a handle on the problem now.I have an Intellitec electronic climate control unit, I gave them a call and the guy told me how to diagnose the problem, and how to disable the furnaces. He said he is 90% sure I have a thermostat problem. So the next trip I will find out what the problem is and disable the furnaces. I did not know that it had a separate controller behind the AC/DC distribution unit. The relay I heard was in the Intellitec controller and it was chattering not arcing. When everyone here was talking about the controller I did not know it was there and thought the problem was in the AC/DC unit. I thought the controller was with the climate control panel up front. Thanks to everyone for their effort.