Heater ducting, do I pay 5 times the price for original?

David2452 said:
Sorry guys, bad day, bad back an very grumpy, still I should not have made assumptions and tried to give a more helpful answer, less pain and grumpiness this morning so perhaps a little late but here it is. The reason PEK is used a lot is because it forms lovely bends and is pretty crush resistant, more so than the eBay stuff linked, which in protected areas is perfectly adequate by the way, but you never get the full extended length from it when you introduce bends, so increasing the price per actual M of run. PEK is not cheap but it is good. However the OP may not have PEK for all I know, Eber used some cheaper grey stuff in their kits a while ago which was not so good. As part of a more considered response I would also look at the install, if the Heater, duct and exhaust are sited low enough down in a locker to get crushed by stuff being bunged in there anyway it may make sense to move it a bit. For areas where this is unavoidable, very few in my experience if the install is well planned, and if the run is fairly straight I have used thin wall solid tube or tube with PEK for the bends, but that is even more expensive.
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Top banana David. We all have bad days. Few ever apologise. Thank you. :)
 
Likewise, I apologise for reacting in a somewhat 'nuclear' fashion! Thanks for the useful info - sounds like it may well be worth paying the extra, certainly in some parts of the run anyway.
 
since replacing all my ducting ( supplied by you know who) i now actually get heat in the forepeak outlet due to better ducting + lagging the smaller dia sections in lockers.
webasto lagging is expensive but easy & clean to use,it has bade my system much more efficient
 
PCUK said:
Standard loft insulation wrapped in plastic and held with cable ties is excellent and cheap. Let's get away from the 'toys out pram' scenario and return to the question. The Ebay stuff will be fine for straight runs and wide curves.
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But what about for the exhaust hose? Any ideas other than gucci stuff?
 
Exhaust wrap is easily and freely available from motor factors at sensible money, they also often have stainless tie wraps, it's tape so a bit less tidy than sleeve but effective. I have found a source of silica sleeving from 25mm to 125mm bore whilst looking for something neat for 75mm exhausts, it's on 100' spools but just waiting for a price. Mikuni do some lovely stuff, a silica thermal barrier coated in silicone, you can easily hold it after the heater has been running for ages. I do think it's an area that shouldn't be scimped though, cheap and cheerful will not do on exhausts.
 
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David2452 said:
I have found a source of silica sleeving from 25mm to 125mm bore whilst looking for something neat for 75mm exhausts, it's on 100' spools but just waiting for a price. Mikuni do some lovely stuff, a silica thermal barrier coated in silicone, you can easily hold it after the heater has been running for ages.
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David, I'd be interested in both the above, please do post the cost information when you find out, thanks.
 
For the the first 2 meters from the heater I think it's essential to use the real deal, the temperatures can be extremely high, particularly if you have a bend. In fact I think you're not supposed to insulate the first metre - is that right David?

After that I think the cheaper (not cheapest) stuff is fine, particularly on the insulation.
 
I can confirm that I really am that penny pinching scrimper! But in the scheme of tubing pricing that silicon covered insulation is actually less expensive than I expected!

I guess that in a locker, with a straight run a solid ali tube with plumbing insulation would be both the sturdiest and cheapest way to duct the heated air, but not so easy to sort out joints, bends, etc.

Rob.
 
rob2 said:
I can confirm that I really am that penny pinching scrimper! But in the scheme of tubing pricing that silicon covered insulation is actually less expensive than I expected!

I guess that in a locker, with a straight run a solid ali tube with plumbing insulation would be both the sturdiest and cheapest way to duct the heated air, but not so easy to sort out joints, bends, etc.

Rob.
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the stuff you mention gets hard with heat & i wouldnt use it near the heater end of the duct
 
Lazy Kipper said:
For the the first 2 meters from the heater I think it's essential to use the real deal, the temperatures can be extremely high, particularly if you have a bend. In fact I think you're not supposed to insulate the first metre - is that right David?

After that I think the cheaper (not cheapest) stuff is fine, particularly on the insulation.
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Uh oh. I insulated mine right up to the heater. I used Webasto tube lagging as supplied by David of this parish. Seems OK. Should I be worried?
 
Lagging up to the heater is the norm, it usually doesn't cause any problems, that said there were some small problems with overheat on systems that were already at the limit of back pressure through too bendy, small a bore or long systems, this coupled to a reduction in the cut out sensor limit when the EU introduced new specs for the things, even then only on a handful of ST 3.5 & 5000. I always insulate with thermoduct, and I always insulate up to the heater hood and have personally never had one with the problem. On useful tip on lagging, if you go through a clothing or similar locker then leave about 100mm uninsulated to get a bit of warm air circulating in there, a little vent top and bottom helps this to work very nicely.
 
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Just find a ducting specialist and buy what you need in diameter required and length.
As far as exhaust piping is concerned flexible stainless hose is readily available or you can make one up of copper domestic plumbing pipe with compression bends or stainless if you want.
I have used copper large bore pipe and compression elbows to great effect on a small engines dry exhaust which has lasted 20 years no problem.
 
My Mikuni MY16 was supplied with a wire reinforced flexible plastic duct which has smelt of hot plastic since new. I have insulated the whole length, actually got smoke in the cabin with that then all but the 1st metre which lost the smoke but it still smells. I did take it up with the supplier who said the smell will wear off, well it hasn't after 15+ years so I'm most interested in other ducting systems.
 
David2452 said:
You are exactly right, I am simply interested in margins, no honest advice is given, any of my customers will confirm that for you, I suggest you go with the samples of one offered. That's me done on here.
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Well, Skyflyer and David 2452, I peruse this forum to glean information as to how to maintain and improve my boat, and I am a little disappointed at the exchange between the two of you, so far I would have thought that two grown adult could behave in a more considerate manner.
 
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