I am fitting my heater and having some difficulty with the heaterbox to bulkhead seal.
The old one was purloined by mice as nest building material so dont have a reference.
The new seal seems to be about 20mm to long. It fits into the heaterbox aperture with the cutout corner in the right place, coinciding with the box cutout but it sticks out by 20mm which surely is too much to compress.
Anybody any ideas.....my inclination is to cut the seal.

Thx.

I've just been faced with the very same dilemma this week. My seal also had c.20 mm extending beyond the metalwork, which seemed too much. The way I fitted mine was firstly to wipe the surfaces with solvent to clean off any residues and then glue it to the heater box using high temperature contact adhesive, on the inside of the heater box aperature. I then loosely fitted longer M6 bolts to the lower fixing points, followed by the upper M8 bolts. It was then progressively tightened whilst checking that it didn't splay out from the aperture surround. When in place, I swapped the longer M6 bolts, one at a time for the original bolts. It wasn't easy and required quite a bit of force, but it should fit. I agree that these seals are too deep, but I don't know how much they compress with age, so maybe it is intentional.

Before fitting, I made sure all gaps in the heater box were sealed up and fitted some sound deadening to the bulkhead below the heater location. It now blows quite a blast!

Thx for this.
I will try the long bolts technique.
Perhaps the original LR seal was more easily compressed as I cannot believe that LR would have had to do this on initial assembly.

TR3a said:

Thx for this.
I will try the long bolts technique.
Perhaps the original LR seal was more easily compressed as I cannot believe that LR would have had to do this on initial assembly.

Click to expand...

If they did they probably had a big clamp jig they could whack on to squeeze it all together

The original seal on my shed was made from open cell foam, but the replacement was closed cell foam, which was a darn site to compress in my case. Perhaps the material properties are wrong and it should be more compressible? Well, it did come out if a blue bag......!

Didn't have a problem with the BP seal when I fitted a new heater to my 1986 90. Yes it is deep but it compresses ok and provides a perfect air-tight seal.
I have had the heater out twice now, once about 16yrs ago to replace the motor and the original seal was found to be compressed, rigid and disintegrated on removal. I fitted a BP item and it went on without problems. I then removed the heater again a few years ago (to have my bulkhead galvanised and while I was at it to fit a brand-new heater assembly) and despite having been in place for over 10-years the seal was still in excellent condition. That said, of course I replaced it with another new one as hopefully it will now stay in place indefinitely.

I know it’s a blag, I’m sure I used draught excluder on mine

Still runs nice and hot

Yes it did come in a blue bag!!
I shaved 5mm off and it fitted nicely.