thirtle26 Posted November 3, 2012 Share Posted November 3, 2012 We have an Eberspacher Combitronic air and water heater fitted to an Autocruisen Sarasota. The blown air heater ducting runs underneath the van and is exposed to the elements. During cold spells the fron of the van is ok as the ducting is near the heater. However the rear is significantly cooler I think due to the ducting being exposed to a longer run. Does any one have any suggestions as to how and with what I can insulate the ducting. Attached are pictures of the underfloor ducting. Link to comment Share on other sites More sharing options...
Hawcara Posted November 3, 2012 Share Posted November 3, 2012 Sorry there are no pictures. :-S Link to comment Share on other sites More sharing options...
thirtle26 Posted November 3, 2012 Author Share Posted November 3, 2012 Sorry. Thought I'd attached 2 pictures. Went to attach a file after posting but nothing seems to have happened. How do I attach? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 3, 2012 Share Posted November 3, 2012 thirtle26 - 2012-11-03 12:01 PM Sorry. Thought I'd attached 2 pictures. Went to attach a file after posting but nothing seems to have happened. How do I attach? It's possible that the file-size of your photos is too large (evidently there's a 100kb limit) - this earlier thread may help: http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=26731&posts=16 Blown-air trunking run externally will (or should!) be weatherproof and have an insulated outer wall. A longer run of trunking will inevitably tend to lose more heat than a shorter one. Consequently, even if the exposed trunking on your Sarasota has an insulated wall, adding further insulation can't but help to retain the heat. CAK Tanks markets a wrapping material intended for insulating a motorhome's external water tank(s) http://content.yudu.com/Library/A1w86o/2012CAKTanksCatalogu/resources/20.htm and it's quite possible you could use this to insulate your blown-air trunking. Even better would be to insulate the trunking, then fit a 'box' over the insulated trunking to provide additional weather protection Link to comment Share on other sites More sharing options...
Auditor Posted November 4, 2012 Share Posted November 4, 2012 I had a similar problem with the heatiing ducting on my Motorhome, and insulated it with this, http://www.screwfix.com/p/spiral-wrap-50mm-x-7-5m/62194%3bjsessionid=Rts2QWqKvCHR4stpNQknRCcNphG7KJyYNvLLJx3VcQty7q2W4y9B%21-1814059857, It certainly improved things, but I think the main issue was probably the length of ducting involved. Link to comment Share on other sites More sharing options...
Harvey Posted November 4, 2012 Share Posted November 4, 2012 I have the very thing that you need on my Starblazer. It is a large version of the pipe lagging tubes used for insulating domestic central heating / water pipes. My 'van was fitted with it when I bought it but I know of someone who bought some and fitted it to his Autocruise. I will contact him to find out what / where from. Will be back. Harvey Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 4, 2012 Share Posted November 4, 2012 Whatever is used for insulation should not trap water. Water-saturated insulation material next to the warm-air trunking will do more harm than good, particularly in really cold weather if the water in the insulation material freezes. Link to comment Share on other sites More sharing options...
Harvey Posted November 4, 2012 Share Posted November 4, 2012 Derek Uzzell - 2012-11-04 9:52 AM Whatever is used for insulation should not trap water. . Yes, the stuff on my 'van is what I think is called 'closed cell'. Harvey Link to comment Share on other sites More sharing options...
T8LEY Posted November 4, 2012 Share Posted November 4, 2012 Long heating duct runs will have more resistance to air flow than short ones. The swivel vanes at your duct outlets are for adjusting air flow. If you have the vanes on the short runs more closed than the ones on the longer runs you should see an improvement in heat distribution. Link to comment Share on other sites More sharing options...
Brian Kirby Posted November 4, 2012 Share Posted November 4, 2012 T8LEY - 2012-11-04 12:25 PM Long heating duct runs will have more resistance to air flow than short ones. The swivel vanes at your duct outlets are for adjusting air flow. If you have the vanes on the short runs more closed than the ones on the longer runs you should see an improvement in heat distribution. Agreed! And, while you're at it, have a good look along the duct to the rear for any kind of obstruction, crushed ducting, disconnections at joints/elbows etc. There is only one fan trying to push the hot air out of the heater. If one route is easier than the other, air, being like water lazy stuff, just takes the easiest route. First make sure the route to the rear is as easy as possible, then make it harder for the air to get out at the front, and more will go to the rear. Only then try insulating. It will make a small difference, but not much. Link to comment Share on other sites More sharing options...
Guest pelmetman Posted November 4, 2012 Share Posted November 4, 2012 Do they really route heating ducting outside the van? 8-)............Its no wonder we've got global warming :D Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted November 4, 2012 Share Posted November 4, 2012 pelmetman - 2012-11-04 1:42 PM Do they really route heating ducting outside the van? 8-)............Its no wonder we've got global warming :D Its a nonsense.....really daft idea, heater hammered by the elements as well. I would never have a van with one Link to comment Share on other sites More sharing options...
Harvey Posted November 4, 2012 Share Posted November 4, 2012 I have answer; Armacell / Armaflex. These people sell it:- http://www.pipelagging.com/index.php but I can't see any with id big enough for the 'van ducting on their website. There will be other suppliers, or maybe the manufacturers can supply direct. hth ( more than some of the other posts :-D ) Harvey Link to comment Share on other sites More sharing options...
crinklystarfish Posted November 4, 2012 Share Posted November 4, 2012 thirtle26 - 2012-11-03 11:43 AMWe have an Eberspacher Combitronic air and water heater fitted to an Autocruisen Sarasota. The blown air heater ducting runs underneath the van and is exposed to the elements. During cold spells the fron of the van is ok as the ducting is near the heater. However the rear is significantly cooler I think due to the ducting being exposed to a longer run.Does any one have any suggestions as to how and with what I can insulate the ducting.Attached are pictures of the underfloor ducting. TRUMA SPARE 40681-00 Go nuts. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 5, 2012 Share Posted November 5, 2012 Harvey - 2012-11-04 6:01 PM I have answer; Armacell / Armaflex. These people sell it:- http://www.pipelagging.com/index.php but I can't see any with id big enough for the 'van ducting on their website. There will be other suppliers, or maybe the manufacturers can supply direct. hth ( more than some of the other posts :-D ) Harvey This lInk details the ducting available for Eberspacher heaters http://www.hallselectrical.co.uk/eberspacher-heating/eberspacher-heater-ducting.html?limit=100 and Armaflex duct insulation is mentioned. The insulation is available for wide-bore pipework http://www.onlineplumbingsupplies.com/m_totalInsulation.asp but not necessarily in small quantities. I'm pretty sure that thirtle26's Sarasota has an Eberspacher Combitronic "Compact" diesel-fuelled heater, where all the 'gubbins' are housed in a single box designed to be fitted beneath the motorhome's floor. The air ducting for this heater will be weatherproof, but I don't know how well it's insulated as standard. As has already been advised, if the ducting lengths are radically different, warm air will prioritise towards the shorter ducts. A well-balanced, efficient system will locate the heater near the middle of the motorhome, have wide-diameter air-ducts of roughly equal lengths and (as far as possible) avoid sharp bends in the ducting runs. Adjusting swivel-vanes in air outlets may prove unavoidable with a badly unbalanced system, but it will tend to 'throttle' the system and reduce overall heat output. A properly balanced system should produce adequate heat-output from each air-outlet with the swivel-vanes fully open or removed. It may be that thirtle26's Combitronic air-ducting is already reasonably well insulated (easily checked by running the heater for a while and testing how hot the ducting becomes) in which case it will be the short/long ducting lengths that are producing the hot-front/colder-rear situation not heat loss from the ducting itself. I believe Truma's 40681-00 product is intended more to provide weather protection than insulation. A better option would be Webasto's "Thermoduct": http://www.ebay.co.uk/itm/80MM-THERMODUCT-DUCT-INSULATION-WEBASTO-EBERSPACHER-/390270781074 Link to comment Share on other sites More sharing options...
Harvey Posted November 5, 2012 Share Posted November 5, 2012 Yes Derek, it'll be a 'compact' combi as in my Starblazer. The ducting in your first link is what is run underfloor to the outlets. It is just thin aluminium or similar and not insulated. The armaflex that is fitted to mine is as in your second link, more specifically here:- http://www.onlineplumbingsupplies.com/armaflex19.asp It does not seem to be available in small quantities from them as you say having varying numbers of 2meter lengths per pack. At least the op will know what to look for now. The ducting on my 'van is in two short lengths from the combi except for the one to the washroom which goes to the opposite side of the van. The op's layout is different but I am sure that the insulation of these ducts will help a lot. Harvey Link to comment Share on other sites More sharing options...
Mel B Posted November 5, 2012 Share Posted November 5, 2012 JudgeMental - 2012-11-04 2:13 PM pelmetman - 2012-11-04 1:42 PM Do they really route heating ducting outside the van? 8-)............Its no wonder we've got global warming :D Its a nonsense.....really daft idea, heater hammered by the elements as well. I would never have a van with one Agree that its daft, but its a case of weighing up all the pros and cons of a van and making compromises. Our Accent has the heating pipe going outside - the reason it does this is that the heater is in the nearside rear corner and most of the vents are on offside running to the wash room and front dinette, however, if I install new heating piping through the inside of the camper along the nearside (under the bed, fridge housing, and kitchen unit) and put new vents in, the only thing that wouldn't have heating in it would be the wash room which in van conversion isn't a major issue. Not sure which would be best, insulate the existing under-van heating pipes or install new piping inside ... decisions, decisions .... *-) Link to comment Share on other sites More sharing options...
Guest pelmetman Posted November 5, 2012 Share Posted November 5, 2012 Our's is indoors ;-)......................Progress eh? (lol) (lol) Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 5, 2012 Share Posted November 5, 2012 Mel B - 2012-11-05 6:13 PM ...Our Accent has the heating pipe going outside - the reason it does this is that the heater is in the nearside rear corner and most of the vents are on offside running to the wash room and front dinette, however, if I install new heating piping through the inside of the camper along the nearside (under the bed, fridge housing, and kitchen unit) and put new vents in, the only thing that wouldn't have heating in it would be the wash room which in van conversion isn't a major issue. Not sure which would be best, insulate the existing under-van heating pipes or install new piping inside ... decisions, decisions .... *-) Not sure if revising your Accent's heating system so that the washroom is no longer heated is such a great idea - remember this thread? http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=26242&start=1 Logically, it should be simpler (and quite probably cheaper) to insulate the present air-trunking than run new trunking inside the vehicle. Link to comment Share on other sites More sharing options...
Mel B Posted November 5, 2012 Share Posted November 5, 2012 Derek Uzzell - 2012-11-05 6:43 PM Not sure if revising your Accent's heating system so that the washroom is no longer heated is such a great idea - remember this thread? http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=26242&start=1 Logically, it should be simpler (and quite probably cheaper) to insulate the present air-trunking than run new trunking inside the vehicle. Yup - well remembered Derek, but I don't see what point you are making I'm afraid ... can you enlighten me please. :-D As for insulating the existing trunking, that'll probably be my first option ... but until I get my van BACK I can't have a shuftie ... still missing him! *-) Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 6, 2012 Share Posted November 6, 2012 Mel B - 2012-11-05 6:50 PM ...Yup - well remembered Derek, but I don't see what point you are making I'm afraid ... can you enlighten me please. :-D I was questioning your statement " the only thing that wouldn't have heating in it would be the wash room which in van conversion isn't a major issue". Clearly PC Plod (the Original Poster of the earlier thread I mentioned) believed that an unheated washroom in a PVC was an undesirable feature. OK, his requirement - heating the vehicle overnight when carrying out security duties - is likely to be rare amongst motorcaravanners, but I would have thought a good few PVC owners use the vehicle's showering facilities when the ability to heat a washroom will be a definite benefit. For me, deliberately choosing to dispense with a heated washroom would be a perverse strategy whatever the type of motorcaravan involved. I could (perhaps) understand it if your Accent's external air-trunking made the heating system so ineffective that you were compelled to reroute the pipework inside, but I doubt that's the case. Link to comment Share on other sites More sharing options...
crinklystarfish Posted November 6, 2012 Share Posted November 6, 2012 Given the characteristic of a washroom, in whatever 'van, ie designed to be damp, it's vital in my view to heat it, especially if the 'van is used year round. Unless, that is, the washroom is never actually used as a washroom / place to hang wet outdoor gear. Worth noting; heater ducting is sold at predetermined level of compression, and can be lengthened, or shortened by extending or compressing it. When compresses really tightly there is less surface area to conduct heat away from the bore and more warm air stays in the tube rather than being (inefficiently) dissipated to the immediate surroundings. I've squashed and stretched tubing around mine to contain or disipate heat as required. Link to comment Share on other sites More sharing options...
thirtle26 Posted November 8, 2012 Author Share Posted November 8, 2012 Thanks for all your views. Will now sit down and digest them all and hopefully get a warmer lounge area in the process. Link to comment Share on other sites More sharing options...
thirtle26 Posted November 11, 2012 Author Share Posted November 11, 2012 Hopefully here are the photo's Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 11, 2012 Share Posted November 11, 2012 That's a lot of exposed air-ducting! From your photos it looks like adding Webasto "Thermoduct' sleeving should be pretty straightforward. Link to comment Share on other sites More sharing options...
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