Should this 45 degree elbow be scewed together?

[MrLantern]

We can hear the stove collar on our woodburner sucking air in so I was going to re-seal it with fire cement, before doing this I have a question - When looking at the next section of the pipe it's a 45 degree and it looks like the straight pipe leading to it from the stove has slipped down, are these designed to expand and contract with movement or should it be rigid and it's come loose? after doing a bit of basic reading it looks like I shouldn't cement the straight pipe into the 45 but maybe should I drill 3 holes and and secure with self tappers before cementing the pipe back into the stove collar?

Cheers, Sam

 

[stoveliker]

Yes, all pipe connections should have 3 screws in them. We use self-tapping sheet metal screws (though I predrill to the size of the core of the screw myseflf).

Not sure what your code says about the screws, but it's safer to have. Especially if you have a back puff (explosion of combustible gases in the stove), you don't want the pipes to separate with such a pressure wave.

Stove cement will seal for a little but very soon it'll come crumbling out.

 

[MrLantern]

I'm in the UK, I'm not sure on code etc but it seems like good practice either way. Thanks for your help