Changing gate valve in airing cupboard to cylinder

[CPCUK]

I was planning on changing the seized gate valve in my airing cupboard supplying cold feed to cylinder from cold water tank in loft.
The pipe is old imperial 3/4" and the gate valve is also 3/4. I bought a 22mm Pegler compression valve and 3/4 brass olives for the job. Tonight though I'm thinking if the existing olives are knackered and need to come off (I have a puller) and leave the an indentation on the pipe the new olives might not make a good seal.
So, my question is, am I better off just cutting the old pipe near the ceiling and as low as I can go and using a 22 x 3/4 end feed couplers renew the length with 22mm tubing instead? I don't mind soldering if this is the best option. I'll leave the rest of the pipework from the tank etc so I'll still have some old 3/4 in the loft.

Any advice appreciated

 

[petit_pablo]

You could just use the existing nut and olive instead, the thread should be the same but if you do change them and the olive is a bit loose on the pipe wrap some ptfe around the olive before tightening.

It should be fine though.

 

[mfarrow]

I had the same issue recently when trying to fit a new tap at the in-laws. Gate valve was siezed and I ended up snapping whatever's inside I think.

Anyway I was going to renew with full bore lever valve but pipe was 3/4". Conex fitting too so not too confident of being able to use the existing nut.

My plan is to cut just above and below existing valve nuts, fit solder ring adaptor above with new stub of 22mm, 22mm olive one end then 3/4" olive on the other end. You idea sounds similar but I wouldn't go crazy cutting 3/4" pipe out, just take as much as you need.

 

[CPCUK]

The job itself is easy and I did tink of reusing the existing olive and nuts but I'm usually unlucky and an easy job always tends to end up as a bigger job so trying to think ahead with potential issues. I guess I won't know until I take it all apart. I will try and get the original valve turning first as that may stop all the hassle.
Cheers guys

 

[ALCPlumbing]

If you decide to cut pipe and solder you will need imperial to metric end feed sockets as 22mm couplings will be loose on 3/4" pipe. I would defo try existing nuts & olives first. Or jus cut olives with a hacksaw and use 3/4" olives.