Flue on Multi fuel stove does the Tee Cap need sealed?

justwhat

Flue on Multi fuel stove does the Tee Cap need sealed?(cap looks same as below)

if so how? If i use cement then will need redone every time soot is emptied or swept. 

Petriix

Do you mean the cowel on the top of the chimney or flue pipe?
There's a very specific set of regulations around fitting a stove. There are some very good tutorials for (extremely) competent DIYers but the fundamental first step is to familiarise yourself with the regs. If in any doubt, employ an expert as there are life threatening consequences for getting it wrong.

justwhat

Stove already installed . I have just moved into house with the stove. Tee end cap / soot box is already in place. Just behind stove

Jeepers_Creepers

This is a cap which is removed to allow easy cleaning of the flue? And it simply presses into place and is held by the three springy prongs?

I suspect - but don't know - that it is designed to be a snug fit with such a small (if any) air gap remaining that it's considered of little consequence to the 'draw' of the flue. I think I can certainly say that you would not be expected to fire-cement it each time - that would be nuts.

Possibly it might be intended to have a 'rope' seal around it? But I would expect there to be an obvious collar or groove in the contact surface for the seal in that case - is there?

How well - how tightly - does it fit?

The similar item you found above, could you email that company and ask them?

justwhat

it does not fit tight and draws a good bit of air.   Defo not the way it should be.  Descriptions on websites do say it should be sealed. 
https://www.fluedirect.co.uk/7-175-c-tc-vitreous-enamel-175mm-tee-cap-matt-black.html

Apodemus

I'd go for rope myself, glued onto either the edge of the flue or the cap (which would be easier to do and easier to replace, when necessary).

Jeepers_Creepers

Wow - so I was roughly 100% wrong then :-(

What a ridiculous design. If you use cement, it'll obviously need breaking each time but - worse - almost certainly require cleaning away from the mating surfaces too, ready for the next coat - what a bizarre design. (Unless you simply build up a thicker layer each time...)

Will you be DIYing the flue cleans? If not, it might just be a case of leaving this task to the sweep each time - it won't be the first time they've come across this so should not find it particularly unusual.

Can you see a good way of using the rope option instead - would it work? Is there a place for it if done neatly? With a rope seal, tho', the cap would really need to be a snug & secure fit so that when you press it into place - squishing the rope seal in the process - it would have to reliably stay in that position and not allow the the expanding rope to push the cap away again leaving it less than air-tight. (Of course, 100% air-tightness ain't essential).

justwhat

i would say you want it as tight as possible because any air is going to cause more draw. 
i think the stove can be swept from the inside anyway, The cap "may" never need to be taken off.
You can get caps that have a clip , but they still need cemented. 
The T piece is meant to fill with soot over time. The sweep comes in , sweeps the chimney and hoovers the t -piece from inside the stove.(that;s my understanding)
The previous owners may just have been empty the T piece for 10 years lol (they left the septic tank for that amount of time lol 
The cap is off so i can inspect the chimney clearance as it is straight up. (i don't intend to use the stove much)
Thought there  may have been a HETAS engineer or someone on here that had seen one of these caps .
i may sweep it myself as its only going to have lite use.

Jeepers_Creepers

You can try contacting Hetas themselves and see what they say - they have a contact page.

But, if it's as you reckon - you can access that area from inside the stove to clean accumulated soot, and also sweep the flue from the stove itself without having to remove that cap again then, yes, seal it properly (cement) and enjoy. It would only become a pain if you had to do this annually.