Why heat to holding tanks?

[Breadbug]

I just gutted my 75 Tradewind. Omg! All the critter debris!!! While I was removing the furnace ducts I found 2 inch round ducts going into the belly. Why would I want my heat going into the holding tanks every time I use the furnace? I get it that I might need this in freezing weather, but the ducts are not operable. Always open.

When I start my rebuild, should I replace these or remove them? I don't plan on doing any camping in freezing weather. I'm in California and plan on camping here.

[Buttercup]

It was to keep the tanks from freezing, yes. But you certainly can put dampers on them if not needed - I.E. Extended freezing temps while on the road.
We have them too and they were a main mouse highway into and out of our trailer. Now, Kimber doesn't want that furnace run until the ducts are sanitized.

[Ag&Au]

Originally Posted by Breadbug

I just gutted my 75 Tradewind. Omg! All the critter debris!!! While I was removing the furnace ducts I found 2 inch round ducts going into the belly. Why would I want my heat going into the holding tanks every time I use the furnace? I get it that I might need this in freezing weather, but the ducts are not operable. Always open.

When I start my rebuild, should I replace these or remove them? I don't plan on doing any camping in freezing weather. I'm in California and plan on camping here.

If you ever sold the trailer and I was the buyer, I would not be very happy when I discovered them missing. It is standard on nearly all travel trailers to have some heat routed to the holding tanks. I can think of kinds of circumstances that could arise where the trailer could end up stuck in freezing temperatures with water in the tanks.

Ken

[Breadbug]

Ok, I hear ya. So, I have to figure our a clean nice way to duct them and have dampers on them. I am gonna clean and sanitize the main ducts. I don't want critters gettin back in. The belly is really clean but ya never know.

Any good ideas for where to get 2" dampers? Seen any clean nice engineering for them?

[Jammer]

::shrug:: not much air goes through the 2" ducts so you're not going to save much propane by closing them off. Just sayin'.

You might have better luck finding 4" dampers and setting everything up so that the dampers are before the reducer. 2" is an odd size.

[TG Twinkie]

I can't believe they are all that effective; since they don't have a return duct for the air. Most tanks that I am aware of are in an enclosed space; so once you pressurize the space by blowing air into it, the air stops flowing along with the heat. It's like most things in life; the air will take the path of least resistance. If given the choice to flow thru a 2" duct with back pressure or a 4" register on the interior of the trailer it will flow out the register.

[Ag&Au]

Originally Posted by TG Twinkie

I can't believe they are all that effective; since they don't have a return duct for the air. Most tanks that I am aware of are in an enclosed space; so once you pressurize the space by blowing air into it, the air stops flowing along with the heat. It's like most things in life; the air will take the path of least resistance. If given the choice to flow thru a 2" duct with back pressure or a 4" register on the interior of the trailer it will flow out the register.

If they are like the ones in my trailer, the hole is about a 4"x4" hole with a 2" diameter pipe inserted into it. That is plenty of room for the air to escape back into the trailer. Also, since the furnance and tanks are both near the fore/aft center of the trailer, the hoses are short with no restrictive vent on the end. Not to mention that all you need to do is keep the spave above 32F.

Ken

[CanoeStream]

TG Twinkie -- no-return is an issue if construction was watertight. Speaking of which ... would my old '59 VW's belly pan have prevented it from sinking in da lake? (no, I don't think so...) But I agree one would have to be staying at the 'stream to monitor this in really dicey conditions. It does get closer to the line when traveling; ie, no protection at all if you're not willing to run LP underway. Fyrzowt -- ready for your input!

I'm with Buttercup -- put dampers on them. You're not seeing much LP disappear even without dampers.

This becomes a resale issue -- like people who think they're saving something by putting in a dorm fridge (cuz that's their lifestyle) rather than a real RV fridge. It's nice not to have to modify your future travels & dreams because of overlooking this tank heat feature. See http://www.airforums.com/forums/f161...tml#post936582

[Fyrzowt]

Originally Posted by CanoeStream

TG Twinkie -- no-return is an issue if construction was watertight. Speaking of which ... would my old '59 VW's belly pan have prevented it from sinking in da lake? (no, I don't think so...) But I agree one would have to be staying at the 'stream to monitor this in really dicey conditions. It does get closer to the line when traveling; ie, no protection at all if you're not willing to run LP underway. Fyrzowt -- ready for your input!

I'm with Buttercup -- put dampers on them. You're not seeing much LP disappear even without dampers.

This becomes a resale issue -- like people who think they're saving something by putting in a dorm fridge (cuz that's their lifestyle) rather than a real RV fridge. It's nice not to have to modify your future travels & dreams because of overlooking this tank heat feature. See http://www.airforums.com/forums/f161...tml#post936582

OK Bob, now you put me on the spot...

My only comment would be to echo what has already been said. You really need to consider the next owner as well as your own needs. Yeah, chances are that the next owner wouldn't check for tank heat ducting, but rather than pull it out, I would either leave it as designed or add dampers.

As to travelling with the fridge on or off, that's a fight for another thread. Been there, done that.

[Trex]

If you plan to move to Green Bay...keep them! If you plan to live in Califorina, I think you can lose them.

[RaleighAir]

So any ideas how to get heat in here when the furnace has been removed? PO removed mine and just has a catalytic heater now (PO said they just used a little ceramic heater in back). In redoing the rear bath/separation rot, I've removed the filthy and crushed ductwork back there. (i also removed the small "home" elec hot water heater PO had and want to replace with lp/elec, got a dorm fridge too that I want to remove/replace with lp/elec fridge, also no univolt - this thing had been set up to just plug in, not boondock).
Maybe redo the ductwork and just use a small fan to force warm interior air around the tanks? Would some sort of heat tape/mat work to warm holding tanks? Didn't want to go back in with a furnace but I guess I could. Just more time/money and I'm ready to get this thing on the road!

[Fyrzowt]

One other thought regarding mice entering through the ducts.

Run the ducts into a mouseproof grill, or cover the ducting ends with mouseproof screen in the belly area. When thinking mouseproof, think VERY small openings!

[c177tx]

When the temps are above freezing I will run a small electric heater or the heat pump and I have noticed that while not running the furnace and using another heat source: ie electric heater or the heat pump (so in those cases my tanks are not heated with the ducted air from the furnace) the floor is cold and makes the back of the trailer colder. When I use the furnace the back of the trailer stays warmer. The duct going back to the tanks both heat the tanks and the floor above them. just my observations from full timing in my little bambi.