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djdobbins1 · 12-20-2012, 03:28 AM

I just purchased a 2004 Alpine, 40' MDTS and can't get the furnace or heat pump to work. Any ideas?
Freezing in California desert.
Dan

BFlinn181 · 12-20-2012, 04:28 AM

You need charged chassis batteries to power the thermostat. If both heat pump and furnace don't work, sounds like the problem is in the thermostat. You do have LP gas and the stove and water heater work?

"007" · 12-20-2012, 05:17 AM

Welcome to irv2.
See if this thread helps you any.

djdobbins1 · 12-20-2012, 06:52 AM

I should have added more information:
The chassis batteries have half charge and I tried it with the generator running.
The thermostat/controller is on and I have gone through all the modes and settings for both zones.
The propane tank is 3/4 full and the valve in full open.
The stove and water heater are working.

Old Scout · 12-20-2012, 07:00 AM

Freezing in the desert--more information please. Is it really freezing, ie, below 32 degrees? If so, your heat pumps are probably locked out--infact these pumps will usually lock out in the mid 30s. So, couple possibilities--above 40 degrees, and both pumps [assume you are on shorepower or genset] and propane furnance [dont think 04s had hydrohot] arent working, there maybe a problem with thermostat. If temps below mid-30s, focus on propane funance as pumps are probably locked. Normally, lockout switches heat pumps to furnance, did you try swithching the mode manually--this can only be done with the front unit/zone [zone 1] selected on the stat.
Lots of things could be in play here--begin with 12v house fuses under sink in bathroom. Does stat function--that is, display temp numbers/modes? Assume you have propane and tank valve is open [do you have hot water, if on propane mode; does propane stove work?] Stat has reset function--not sure how to do, do you have furnance and stat owners guide/instructions?
If none of these things help, you probably have stat or furnance issues that will require a tech....good luck....

Old Scout · 12-20-2012, 09:33 AM

PS--access to the propane furnance is limited but I do recall having a similar problem and was able to remove the outside access cover to the furnance. Once the cover was removed, I was able to see that an electrical connection/plug had vibrated loose from the small motherboard that controls the furnance. Reconnected the plug to the board and the furnance worked fine. This is a long shot but you might try removing the cover. Other than checking for loose connections, checking the condition of the burner exhaust pipe or the cage fan/housing is about all us untrained owners can do.

EngineerMike · 12-20-2012, 09:41 AM

Thermostat has a delay (that I've never understood, seems like sometimes it takes forever to come on, sometimes 2-3 minutes, sometimes instantly, but maybe I'm on crack again & forgot I'm high). I've frequently thought tsat-controlled item wasn't working then several minutes later it came on.

BigSkyBob · 12-20-2012, 09:42 AM

Is the propane detector light on (green on mine). If you have a Hydro-Hot the control board will lock out with low battery voltage and has to be reset manually.

Old Scout · 12-20-2012, 10:23 AM

Think we are talking propane furnance issues here, not hydrohot--but correct me if I am wrong....

tinytom · 12-20-2012, 11:01 AM

Furnace will only work when selected in zone 1 on the thermostat. When trying to use reverse cycle heat make sure furnace is not selected in zone 1 or 2. If it is it will lock out the reverse cycle heat

Jim A · 12-20-2012, 08:36 PM

I have an '04, and the propane furnace will usually kick on almost immediately. Make sure both zones are set to the furnace to eliminate the situation tinytom mentioned. And set to a high enough temperature, of course.

The heat pumps (or air conditioning as well) will definitely have a delay of a couple of minutes. And if the outside temp is much below 40°, they don't operate.

Within the first year of ownership, my propane furnace stopped working. The dealer had to replace the control board under warranty. And the replacement board died during their testing. The furnace manufacturer had an upgraded control board that fixed the problem. If the fixes mentioned by posters does not fix the problem, that might be a possibility. (My furnace at home failed last week/this week due to a defective furnace control board, so I am sensitive to that problem right now!)

But neither one working sounds more like a thermostat problem. (Or a new owner problem!

) The thermostat and furnace are 12 volt systems. It is designed to work with or without shore power, but I am sure there is a minimum battery voltage requirement. From my experiences the batteries can be relatively low and it will still work. Heat pumps are 120 volt, of course, but the thermostat still operates on 12 volts, so you need both available to use them.

firedoc · 12-20-2012, 08:59 PM

OP what do you mean that batteries are "half charged"?

djdobbins1 · 12-21-2012, 11:14 PM

Here is an update:
Batteries are fully charged
Both heat pumps are working well
Furnace fan comes on, but won't light. Can't hear the ignitor firing. Is there a way to access the furnace to check the fuel valve and ignitor? Looks like it is burried under the the bathroom sink cabinet. Thanks to everyone for their responses.

bcbowers · 12-22-2012, 05:03 AM

Dan,you'll probably find the furnace inside a storage compartment right under the floor. In fact, if you look on the outside of your coach for the chrome vent there you'll find the furnace. If the furnace is coming on then you should be able to "hear" where it is in the coach and look outside directly under that location. It should be enclosed in a "box" that can be accessed by removing screws.

Mine is in the PS compartment just in front of the rear wheels but my coach is an 03 with front door so probably different. Hope this helps.