Sealing heater from allowing outside air coming inside.

Hi,

Here is a short list of items that need to be dealt with if planning for the possible -40 weather often seen in Montana.

Fridge anti freeze protection

Outside shower (if any) needs to be insulated

Compartment doors insulation beefed up.

Waste tanks and valves may need additional heating

Consider skirting the entire unit and adding a heater underneath

Add an electric mattress pad heater

Replace the 120 volt outlets where heaters will be used. I prefer oil filled heaters because their surface temperatures are much lower. Walmart sells some 1/2 size units that can be tucked away in spaces that are otherwise essentially wasted space.

Add a second shore power cord that can be used for providing electric heat. (I have the OEM 30, a 20, and a 15 amp).

Arrange rental of a 100 pound external tank and a extend-a-stay fitting to allow it to be used. The on board tank should be kept "in reserve" and in extreme cold may only last 72 hours.

You really have little time left before the cold moves in for the fall. Last December it was -36 C (-33 F).

Is it the flow of cold air around the exterior service panel that is the problem?If that panel isn't secured tightly, you could either reseal it with butyl tape or caulk around the perimeter with a good sealant. I like the Geocel sealants like ProflexRV.

As others have remarked, the combustion air intake and exhaust are in a contained space with the burner chamber. THere should be no cold air from the exterior exiting that shared space.

Using the plumbing system in a Montana Winter will require the furnace to run almost continually and preparations will have to be made for keeping the waste tanks and drains unfrozen. This usually involves heat tapes, tank heaters, and added insulation.

RV furnace fan comes on and blows cold air thru duct work because the same motor is blowing air thru combustion chamber to purge it before gas flows & is ignited.

Then after thermostat set point is reached the gas flow is secured but the fan motor continues to run (timed event) to cool down heat exchanger....that results in warm/cool air being blown thru duct work.


If this is what you are experiencing and think it is due to 'outside' air ......it is a normal RV furnace cycle.

If this is NOT what you are experiencing then explain what is going on/how you are getting outside air in AND not run furnace anymore until repaired because outside air getting inside RV via furnace means combustible products (propane fumes, CO) are coming in also.

The exterior furnace vent should connect direct to the combustion manifold and not let any cold air or combustion gasses into the RV. Otherwise RVs are not exactly sealed that tight.

I installed a pump to circulate warm water to prevent frozen pipes. www.ultraheat.com for the tanks. Heat tape and insulation for exposed drain pipes. I also use a 1200 watt radiator style heater to supplement the furnace in winter.

Don't do anything to it. As explained above, it isn't causing any cold air to infiltrate the RV and if you do anything to it you risk carbon monoxide poisoning.

Your return air is from inside the trailer not outside. Outside air is for combustion only, furnace will not function without it.

Just like a air-conditioner, The furnace has no direct air connection between the out side air and the air inside an RV. If you have outside air coming in, you have another problem. It may be possible that the furnace air intake has come loose allowing outside air to come in. I would check both the air intake and the exhaust.

Hi,

I suggest you read the winter camping thread in the full time rv'ing forum.

How do you mean the heater is "open"?