Heiki mini 400x400 bathroom vent.

Feb 9, 2008
7,445
13,126
Corby, Northants
Funster No
1,455
MH
Coach Built
Exp
Since 2007
I need to replace the whole unit when I return to the UK. Has anyone any experience of replacing one? I have looked at a couple of U- Tube videos and it looks quite straight forward. Just remove the retaining screws from the inside, then from above, using cheese wire cut through the mastic seal that holds the top section to the bottom section and seals against the elements.
I would welcome advice from those have experience on the matter.
Picture of unit to be replaced, below.
Thanks in advance.
 

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Jun 30, 2011
5,204
9,839
Durham
Funster No
17,128
MH
Concorde Concerto
Exp
Since 2007
Yes its straightforward, I think you will only need to use cheese wire it its been sikaflexed on. With flexible mastic you need to push from below with a lump of wood after undoing all screws etc.
That's what I did anyway and its eased off. It depends also how long its been on to how secure it is, also as mentioned what was used to stick it in the first place.
Hardest part is cleaning up the old unit if re-fitting and cleaning the area on the roof where its going to be stuck down.
You are fitting a new unit completely so only the roof area to clean up, simples.
 
OP
PhilandMena
Feb 9, 2008
7,445
13,126
Corby, Northants
Funster No
1,455
MH
Coach Built
Exp
Since 2007
Thank you for your kind input. It will be silkaflex as it is the original build from new. I will remove remaining seal with white spirit and rub down the sealing area with sandpaper and clran again to ensure a obtain a good grip when replacing new unit.

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Aug 6, 2013
10,986
14,009
Kendal, Cumbria
Funster No
27,352
MH
A Class
Exp
since 1999
It will be sealed with butyl mastic. You can use the same to replace it. A kitchen plastic spatula and a thin flexible steel blade will get it off. The remains can be removed by the same method finishing with white spirit for the last bits. White spirit dissolves it. I hope never to come across one held with Sikaflex PU adhesive! I haven't as yet in either German or UK caravans or mhs.
 

Minxy Girl

LIFE MEMBER
Aug 22, 2007
26,112
42,603
E Yorks
Funster No
149
MH
Carthago Cmpct i-138
Exp
Since 1996 we've had Elddis, Swift, Rapido, Rimor, Chausson MHs and Autocruise & Globecar PVCs
One of the best 'scrapers' for the residue is a 'sharpened' credit/debit card (old ones preferably!) as they can get it off without causing damage to the roof. As mentioned it's removing the residue that will take time ... I replaced 2 roof lights on a Rapido (it has smoked glass ones and it was like the black hole of Calcutta) and cleaning off the 'gunk' etc easily took the vast majority of the time!

Oh ... a tip, when putting on the new mastic put a strip of masking tape around the aperture on the roof, at the outer edge of where you want the mastic to finish, then put the mastic on ... once you've fitted the new roof light you can remove the tape and it should leave a nice straight line on the edges ... saves a lot of cleaning up!
 
Jan 3, 2008
2,767
4,158
Anywhere the camper takes me
Funster No
1,118
MH
Looking
Exp
20
Thank you for your kind input. It will be silkaflex as it is the original build from new. I will remove remaining seal with white spirit and rub down the sealing area with sandpaper and clran again to ensure a obtain a good grip when replacing new unit.

I used this on my Rapido rooflight,

http://www.johnscross.co.uk/products/Sikaflex-512.html

Excellent stuff. Masking tape around the apperture gives a good finish. I know its difficult to remove but that's not a problem, if I ever need to replace the rooflight again it will be damaged anyway and the joint is easily separated with fishing line used as a cutter.
 

scotjimland

Free Member
Jul 25, 2007
0
-12
.
Funster No
15
MH
.
Exp
.
if I ever need to replace the rooflight again it will be damaged anyway

but it may leak again, then it may be damaged getting it off..

Sika is an excellent adhesive / sealer, and it has it's uses, eg. joints between wall and roof panels.. but it's not advisable for sealing roof-lights and windows. which should have a non-setting mastic.

Sika doesn't allow for the different expansion amounts between the aluminium roof surface and plastic window frame .. this can cause leaks.. also if you walk on the roof near the window it can split the seal.

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Jan 3, 2008
2,767
4,158
Anywhere the camper takes me
Funster No
1,118
MH
Looking
Exp
20
but it may leak again, then it may be damaged getting it off..

Sika is an excellent adhesive / sealer, and it has it's uses, eg. joints between wall and roof panels.. but it's not advisable for sealing roof-lights and windows. which should have a non-setting mastic.

Sika doesn't allow for the different expansion amounts between the aluminium roof surface and plastic window frame .. this can cause leaks.. also if you walk on the roof near the window it can split the seal.

Perhaps for ordinary Sikaflex yes, but I have had no problems with mine and I regularly walk on the roof when cleaning, as for expansion and the seal splitting I just read the product information o 512 and was converted. I did once agree that Sikaflex adhesive should not be used, however that was before I looked into Sika 512 which was developed for caravans / motorhomes were an elastic seal was needed, to quote the Sikaflex data sheet:-

Joints produced with Sikaflex 512 Caravan are strong, watertight, permanently elastic and do not shrink.

I appreciate what you are saying and am not arguing just relaying my experience of it. So far so good, mine has been in place for around two years now and there are no signs of any degradation of the seal. If it ever leaks I will report back.
 
Nov 4, 2011
3,741
16,916
Uk
Funster No
18,763
MH
A class
Exp
2001
I will still use idl99 when I replace my other heki soon,
also Sikaflex 512 is a lot dearer than idl99.
Just my opinion.
 
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