Insulating External Heater Duct

[Tonyex]

Like many vans my series 6 Indiana has a heater duct under the floor to get from the heater to the front of the van. This gets very hot and therefore is a potential heat loss. I am considering insulating it using injected foam between the black outer duct and the inner heater duct. Anyone got any observations?

 

[SteveW77]

I used to use this stuff years ago, when I worked for Electrolux.

It could be tricky, as nothing will stop the process once started, if you used to much it will come out every where and make a real mess. It's not the easiest stuff to clean off, still I will watch with interest if you do decide to do it, as my end bathroom is bl**dy freezing.

Steve W

 

[Tonyex]

Thanks Steve, I've used it before and it can be messy - it expands at a rapid rate if not used with care!

I just wondered if anyone had tried to insulate this duct and with what success.

 

[MikeAce]

after suffering a cold bathroom last winter i intend to make some alterations this year, i am going to run an extension lead under the van to the inside of the cupboard in the bathroom, it will be hard wired to the fuse box. inside the cupboard i will fix a fan heater (over heat potected) to the side wall and turn it on when required. much easier than insulating the existing ducting.

and i dont plan on having it anywhere near water before i get shouted at.

 

[cris_408518]

You may find that the foam just yellows and shrinks and crumbles when it gets hot.

Our last van had the bathroom all but next to the heater, even with the heater vent closed it would get very hot as hot air escaped past the flap that only partially closed. The rear end dinette area would only get mimimal warm air flow as the juntion to me was fitted in the wrong way and the air took the easy route to the bathroom vent.

A previous van had similar problems with no thought given by the manufacturers re how the warm air distribution is equalised.

Again a T junction where the feed comes into one side of the T's top with the flow straight across leaving the vent that's on the end of the T's upright getting next to no air flow.

Manufacturers often route the air pipes further than needed as that is the easy way during the build.

Try looking at the pipes junctions and working out where the air flow is taking the easy route, a piece of alluminium shaped and curved and masticked into place 1/2 way across the juntions will direct air where it's needed. See if you can shorten some of the pipe runs. Make sure that they junctions and pipes are all air tight.

Pipes running through backs of lockers that get holed by awning poles and other gear make for warm lockers but cool living areas.

Larger high speed extractor fans as used as exhaust extractors for computers are near silent running and run off low voltage and cut into the pipe run to where you want the heat they will pull and push on the warm air.

 

[WatsonJohnG]

Mike, if its too cold at one end have you tried altering the flap on the back of the heater pipe where it splits on the heater casing.

I always put an extra vent by the door so that air coming in/under the door is warmed.

In the fixed bed Oklahoma there is a big heat build up in the cupboard by the heater and a vent in the piping there is letting the hottest air straight into the van.

This will allow less heat loss underneath as its already in the van body !!

 

[Tonyex]

JohnG, I think the extra outlet near the door is a good idea, my layout is similar to the Olklahoma for that. I have balanced the air flow at the heater - the first thing I did as I haven't had a van where it has been done at works yet!

I take on board Chris's comments about the foam crumbling; as this duct is barely 1m long I will also look at wrapping it with insulation and a waterproof covering.