80/125mm combi boiler flue extensions compatibility

2 Jun 2003
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United Kingdom
Could somebody please tell me whether it is possible to use other manufacturers' flue extensions with Worcester Bosch 28i jr combi boiler?

The boiler location is in the kitchen, where there is no external walls, and the flue needs pass the bedroom before it reaches the nearest external wall.

I am having an independent ceiling installed for sound-proofing, and wanted the flue to run within the new ceiling void. I understand that there needs to be inspection panels in the ceiling to allow servicing of the boiler/flue system.

If I were to use longer extensions, I would minimise the number of joints, thus fewer inspection hatches.

Worcester Bosch only sells 1m extensions, but I've seen 2m long extensions by other manufacturers (e.g. GLowworm)?

My Corgi engineer is not sure whether they are compatible.
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The condensifit worcester flue uses's a pushfit style rubber connection. Glowworm/vaillant use a clamp on the outer seal. You might be able to but would expect the manufacturer to state in the book only there stuff to be used.

How far do you have to go with it in ducting?

I always pop rivet mine together although reg's would still require the inspection panels.

Hi Sam

The flue needs to run for about 6 metres, 3 of which is in the bedroom, and the other 3 m is in the bathroom before it connects to the boiler at the other side of the studwall in the kitchen.

Due to the position of the boiler and restrictions at the external wall (window openings), the flue can't be installed in a straight run, thus 2 elbows needs to be installed in the bathroom ceiling.

If I were to use Worcester flues, I would need 2 hatches in the bedroom and 1 larger hatch in the bathroom.

What about the Vokera flue extensions? They have them in 2000mm and 3000mm long extensions, and also appears to be of the push-fit fitting.
If flue parts from Glow Worm or Vokera are better suited to your install than Worcester :idea: Fit a Glow Worm or Vokera Boiler :rolleyes:
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balanceed flue allowed is 6 mts and if you have 2 # 45 and a 90 degree setup 500mm for each angle is 1500 mm deduction
can you not go straight up and out through the roof / no bends needed.
the other option would be twin flue system you are allowed to get longer runs with that
It always helps us to give the best advice if we are given all the information to start with.

We are only guessing at whats going on.

Is this a new expension and new boiler?

Have you chosen this as a new boiler for some very odd reason?

Have you been given this boiler an dwant to use it regardless of cost or complication?

Flues are very expencive and its almost always cheaper to site the boiler on an external wall rather than have a long distance of flue extensions.


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