thinking to insulate some 28mm boiler return pipes with expanding foam
- any gotchas?
i expect max temp to be 85deg C... does it degrade at high temps? or anything else undesirable? fire rated safer than ordinary? ??
cheers Jim K
On some boilers, the manufacturers instructions say that a certain length of pipe (both feed and return) must be left uninsulated.
how long and any ideas why?
ta Jim K
I think it's in case the pump circulation cuts off unexpectedly (e.g. power cut), and the boiler needs to dissipate the residual heat in the heat exchanger.
Don't know about your application but on Top Gear, Richard Hammond tried to use it around hot engine parts on his 'damper van'. Ended up suffering the consequences.
can we presume they were a lot hotter than 85deg C tho? i.e. 85 deg C is "hot cup of tea" realm....spose a boiling water test is required...
cheers Jim K
it will char at several hundred. Its fine up to 100C.
test by putting bits in boiling water?
It does degrade slightly, it goes brittle, similar to that gritty sponge stuff that flower arrangements are put into, although not to that extent, but I wouldn't use it for this purpose if I were you, simply because it's a PITA if you ever want to work on the pipes again, far better to use the split foam pipe insulation, easily removed, less mess and cheap as chips.
mmm that's where I am starting from!! crap thin stuff - move upto the right stuff in right size and costs *a lot* more....
Pipes connected to my heat bank are radiating a lot of heat... I've insulated the heat bank externals (pipes, pumps, heat Xchanger etc) with 2 X =A38 cylinder jackets - which are working well
last few obvious heat sinks now - boiler flow is worst, thought I'd do return as well
the gritty brittleness - is that from UV exposure? sounds like what it does in sun - these pipes never see the sun!!
Cheers Jim K
Cylinder jackets are thin fibreglass wrapped in a plastic bag, why not lag your pipes with fibreglass too?
It could be UV attack as it's outside that I've noticed it happening
I wish this question had been asked last night, I was drinking with Baxi's ex director of development. If he comes in the pub again I'll ask and post back.
Dave
ta ;>)
You could wrap felt pipe insulation over the split foam insulation.
NT
well I could do ... but for a 4quid foam can plus moulds (spare bits of 110 soil piipe split in two or "hinged") I reckon I can cover lots of pipe as thick as I like.. unless the foam won't behave...
Jim K
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Jim K saying something like:
Two layers of the cheap stuff - tie-wraps around the big size. You can get various sizes of it to fit nicely together.
Go for it - after all, that's exactly what some very pricey underground hot water pipe is made from, from what I've seen. How about 25quid a metre?
Why not use the fire proof caulk ... ideal for the job
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