Heat in Underbelly - Montana Owners Club

Montana_1424 · 12-25-2005, 04:11 PM

Does the furnace vent which goes into the underbelly provide enought heat to keep the freshwater tank from freezing? I pour antifreeze in the gray and black tank, but I obviously cant do that in the fresh water tank. I do have the underbelly sealed up pretty good. I used expansion foam in all the little openings.

ols1932 · 12-25-2005, 05:10 PM

In our 2000 3555RL it does.

Montana_1424 · 12-25-2005, 05:13 PM

Cool, I am thinking about just using the tank instead of hooking up, for now

Montana Sky · 12-25-2005, 06:04 PM

In my 3400RL there is a 2" heat duct from the furnace into the underbelly to keep heat around the tanks. I am sure your 3650RK has it as well, just make sure you use the furnace and not just a space heater. The furnace needs to cycle on to blow heat into the underbelly, if you do a search on sreigle post on tanks freezing up, he goes into great detail as to why and how this is important.

Montana_4944 · 12-26-2005, 01:17 AM

Our dealer told us most freezing problems are from keeping the furnace heat to low. We live in ours and were trying to use space heaters to save on propane. In doing that we didn't have our furnace high enough so pipes froze.

sreigle · 12-29-2005, 03:42 PM

Like YorkieSue we found so long as the furnace runs enough the belly tanks will be fine. We've never had a tank freeze up even to five below (F). My earlier report of a frozen black tank was incorrect, as another post described.

Our "new" procedure is we use space heaters to augment the furnace when the temperature is above hard freeze level (27 for four hours). When we retire for the night and the temperature is to be below that level, the downstairs space heater gets turned off, the furnace gets turned down to 60, we close the door to upstairs and run a space heater in the bedroom (ours is one of the models that do not get much heat upstairs).

When the low is to be above the hard freeze point we turn the downstairs space heater on high or low (depending on expected low temp) and let the furnace run only as needed to maintain 60 degrees (sometimes I take it to 58 instead).

I don't know if this approach is good for everyone but it works for us. Having had the belly pan dropped along the edge I found there is plenty of heat in the belly just from the furnace running. A mobile service guy I had helping me recently was quite impressed with the amount of heat in there.

Northstar · 12-30-2005, 02:39 PM

We got down to about 25F early in April this year in Alaska. Our basement had enough heat. Our rate of gas consumption lasted seven days.

genecurp · 01-31-2006, 05:37 AM

We too use the sreigle approach almost exactly as outlined. I even set the thermostat to 55 or even 50 many evenings. The colder the predicted temperatures the more likely I am to set the termostat to 60.

Good luck.

keham · 02-26-2006, 12:21 PM

What have people done to make the bottom panels and side panels seal better.. Looking under mine the way they bolted (screws)the side rolled panels to the frame. It has many many deformed gaps in the metal between those screws.

Montana Sky · 02-26-2006, 04:06 PM

I bought a few rolls of Darko tape and will be going along the edges of the bottom panel and the frame to seal that gap up. Also going to look into spraying expandable insulation into the areas I can. I am doing this for 2 reasons, 1. keep out mice & 2. help keep the coach warmer/cooler.

Garin1 · 02-26-2006, 06:20 PM

The Montana web page says that enclosed heated holding tanks are standard. Does this not include the fresh water tank?

patodonn · 02-27-2006, 07:31 AM

Re colder overnight temps (say..down to 10 or 15 F or even lower) it would seem to make sense to keep the outside water hose disconnected overnight, and use fresh water from the belly tank with the onboard water pump until out of the probable freeezing temp/time band. Probably good to keep the fresh water tank fairly full overnight, add more in the later part of the afternoon if necessary.

Also, how about keeping the thermostat set to 60 or slightly above and block (or partially block) the interior heat vents, especially those nearest the thermostat sensor. That should keep the furnace running longer, and result in a more heat into the belly area.

Comments on the above?

JH Sechelt · 02-27-2006, 09:33 AM

That sounds good to me,

We picked up our new 2980Rl in late November, and went to Vancouver, BC shopping in the middle of
December. It went down to about 20 Degrees F. I unhooked the city water right after supper knowing
it was going to get cold. Kept the furnace at 60 over night but by the morning I had a steady drip
back around the fresh water tank. Of course with the under belly closed in I could not tell where
the water was coming from. When we got home I took the last under belly cover off and still could not
see excactly where the leak was. After playing around with it for a few days I decided it was the main
city water line running inside the trailer. I bought a new piece of pex waterline and hooked it up to
the old one running through the trailer, pulling on the the old waterline I managed to pull the new one through.
The old waterline had a very small split in it. I don't know if it froze or was damaged before we got the trailer.
Anyways its fixed now, and it only cost about $20.00 ( that includes a ball valve I put in the line where it hooks up to the system by the hot water tank. With the check valve at the back you can not get antifreeze into that line, so I blow the water out with air in the winter and close the ball valve so no water can get back in the line when we winter camp.
Like Patodonn says I just use the water on board the unit.

Take Care
J & D

You may also like: