Expansion vessel installation

[rob7475]

Hi,

The internal expansion vessel on my WB Greenstar 30si has failed (water coming out of the valve) so I need to replace it. The boiler is fitted high on the wall so there's not enough clearance to pull the vessel from the back which would mean taking the boiler off the wall. The boilers over 10 year old so I don't fancy the cost of having to take it off the wall and what other problems this might cause.

I'm looking at installing an external vessel. The nearest I can get one to the boiler is about 2 metre away. The return pipe is 22mm speedfit pipe so I plan to use a 22 to 15mm speedfit tee to break into the pipe. The vessel will have a 3/4 thread - am I ok to use one of these to connect to the vessel or is speedfit a definite no no for this?

https://www.johnguest.com/speedfit/product/10-15-22-28mm-size-fittings/straight-tap-connector/

 

[kidgreen61]

You'd be far better off with a 3/4x22 female iron.
Use 15-20 wraps of PTFE tape on the male thread.

 

[rob7475]

thanks, do you mean something like this?

https://www.screwfix.com/p/compress...3dekhJemExKw1M15hTwaAiUSEALw_wcB&gclsrc=aw.ds

 

[kidgreen61]

That's the one

 

[kidgreen61]

Come to think of it, if you're going to use a 22x22x15 tee, then you'll need a 3/4 x15 FI, given that it'll be 15mm pipe going to the EV

 

[rob7475]

Good point. Was planning on 15 as i’ve got plenty of 15mm pipe knocking about.