Did I see someone on here with a proper insulated central heater tube? Looked like it was a twin wall stainless(?) tube with high density foam insulation between the walls....!?! I did a quick search but nothing jumped out at me Cheers
i dont know who that was paul but you can buy prelagged stainless duct which has inner and outer tube . try google prelagged spiral tube or flexy
I need this for one at work as well, thanks for the tip, I spent an hour yesterday looking for something suitable. And having just had a quick google still none the wiser, so if anyone has a good link I'd be grateful.
I used thinwall aluminium, but reduced the diameter to 76mm OD, so I could insulate it properly....also binned the reducer/diverter at the front cross-member, so I could angle the tube to the next hole along (three holes in the cross-member), which puts it on a better path, and gave me enough room to install the propex under the floor...replaced the concertinas with stainless polylock, which have also been properly insulated.... I was going to do a write up and 'how to' but I decided not to: a) because I can't be arsed justifying it when the inevitable questions arise and b) people may have a slightly different set up, so I didn't want to quote specific lengths, dimensions etc. Used 76 OD for the central tube and 60mm ID for the 'concertinas' both insulated with Rockwool and ali tape.....the front ducting has been wrapped in Armaflex tape and re inserted into the the stock corrugated stuff The Propex exhaust and silencer are routed to follow the hard gas line above it....should radiate enough heat to prevent any freezeing....
The spigot from the Y piece at the back is 90mm OD, so make sure if going for the pre-lagged stuff, there's enough clearance to get the belly pan back on....this was why I went down the route that I did, plus Ali is peanuts and light....bit of a faff, but worth the effort IMO.... silicone reducers etc here ....really good service
Thanks for posting Vanorak. ...Far too much faff for me/customer who has/had bigger fish to fry - like no chassis! I just need a one pipe, whack it in solution as it's above the belly pan. Not helpful of VW to make it differing diameter at each end was it!
How about this for quick and easy? http://www.ebay.co.uk/itm/Truma-75m...ervan_Caravan_Accessories&hash=item256b293a25
the original front duct on late bays was basically the same as this, but 70mm ID.. with 90 over the top.....it also had a recycled fibre 'sock' between the two pipes...whether this does or not I wouldn't know.... cheapest solution would be to used 90mm ID ali or steel tubing and then get a clamp on (or weld on seeing as it's you) reducer made up here
I read something a little while ago about someone making some kind of super insulated jacket type thing to go over the metal tubes. Can't remember where I read it though
there's a guy on ebay who's making jackets for the bay system using fibreglass matting.....basically replaces the original coverings...can't vouch for how effective they'll be, but guess it saves you doing the cutting and sewing....
the best bet would be to change to ovalised ducting after the y piece, so you'd keep the same volume, but have more height to insulate properly.....twin wall ovalised aluminium pipe with expanded phenolic foam between the two....
