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95Dolphin · 11-14-2018, 10:46 AM

Hi

I have a 1995 National RV dolphin 535 and was wondering about the dometic roof mounted propane furnace. From what I have read it is okay to let it run while driving but wanted to ask if the 12v power it uses comes from the house batteries or the engine battery?

Seems to me if it is coming from the house battery it could run it down and if coming from the engine battery it is being recharged through the alternator.

Does anyone know which battery is being used ?

jcussen · 11-14-2018, 11:13 AM

Dometic roof mounted propane furnace? Never heard of one of those, If you are talking about a heat pump/ac or ac/heat strip, believe you will need your generator for that. For your regular propane furnace, probably uses house battery that is likely charged by your alternator while driving. If not driving, house battery should run 12 volt furnace blower and controls for quite a while if batteries are good

Polyian · 11-14-2018, 11:53 AM

A confusing question, I have never heard of a Dometic roof mounted furnace.

I'm guessing you have a Dometic Roof Mounted Air Conditioner with a heat strip that needs 110Volt power, either plugged in or from generator.
The propane furnace is normally wall mounted at floor level and manufactured by Suburban or Atwood. These are powered from the 12 volt Coach batteries and burn fuel from the propane tank. You can easily use this while driving without starting the generator (if the coach batteries are charged).

Many (most) Coaches charge both the chassis and coach batteries while driving, you would need to use a multi-meter to check if your alternator charges your coach batteries with the engine running.

95Dolphin · 11-14-2018, 12:10 PM

2 air conditioners and 1 furnace on the roof, all ducted. standard equipment on 1995 Dolphins. And yes sorry, the furnace is atwood.

Polyian · 11-14-2018, 12:13 PM

I stand enlightened. But I don't know anything about it, perhaps best to contact the manufacturer.

-BigRed- · 11-14-2018, 12:15 PM

Will be difficult to contact them since National RV is out of business.

It should draw its power from the house battery. But you should have an interconnect to the chassis so the motorhome will charge the house batteries while you are going down the road.

95Dolphin · 11-14-2018, 12:17 PM

Quote:

Originally Posted by -BigRed-

Will be difficult to contact them since National RV is out of business.

It should draw its power from the house battery. But you should have an interconnect to the chassis so the motorhome will charge the house batteries while you are going down the road.

I guess that is what I am trying to find out if the house batteries are being charged while driving or not.

Polyian · 11-14-2018, 12:18 PM

I was referring to the manufacturer of the furnace, apparently Dometic. It's not clear to me if this furnace is electric or propane.

95Dolphin · 11-14-2018, 12:21 PM

Quote:

Originally Posted by Polyian

I was referring to the manufacturer of the furnace, apparently Dometic. It's not clear to me if this furnace is electric or propane.

Propane and as I corrected in the earlier post it is atwood (which is now owned by dometic)

HJLowell · 11-14-2018, 12:25 PM

They certainly should be while the engine is running .
The Alternator should charge both battery banks.

You can start the engine and do a simle test.

Check the volts on both battery banks and you should see 13.6 to 14 if your alternator is functioning properly.

Podivin · 11-14-2018, 12:26 PM

Does the rig have 'salesman' switches for chassis and house batteries?
If so try turning off one of those switches and see if the furnace runs.
If it does, turn of the other switch.
Hopefully that way you can determine which power source it's using.

95Dolphin · 11-14-2018, 12:29 PM

Quote:

Originally Posted by Podivin

Does the rig have 'salesman' switches for chassis and house batteries?
If so try turning off one of those switches and see if the furnace runs.
If it does, turn of the other switch.
Hopefully that way you can determine which power source it's using.

It has a store switch if that's what you mean. I will try that and John Haggards simple test and see what happens.

Thanks to everyone for the help and suggestions

jcussen · 11-14-2018, 02:42 PM

A unique system, you can learn something new everyday. Easier still, start furnace and remove one lead to your start battery, if it continues to run, you have your answer.

cimplexsound · 11-15-2018, 07:51 AM

In your year of RV the furnace is hard wired to your house battery which is kept charged by your inverter or generator when you are not plugged in. You probably have an Atwood hydroflame furnace most common in that year of RV. If not its a Suburban. All are 12 volt DC models that run directly from your house battery. The Atwood hydroflame is still a very popular furnace and is still installed in many modern Motorhomes today.

1979 Dodge Tioga Class C 24 foot. 1987 Fleetwood Bounder 34 Foot.