Replacing old TRV with a new one

[b0ng0]

I have a leaking Myson One-Way TRV on a radiator that is leaking from the pin fairly consistently, so I am planning to replace it. This is probably the most advanced bit of plumbing I will have attempted to just wanted to get some advice from more sage members.

1 - I am replacing it with a Myson 2-Way TRV, which is a 15mm valve - however the pipes going to the rad are 10mm. I have bought a 15-10mm reducer but have no idea how to fit it. Would the order of components go like this:

Nut onto the 10mm pipe -> olive on next (the one that came with the 15mm valve) -> reducer -> valve -> tighten the whole thing up? I've tried to assemble it this way as a test and it seems like the reducer is stopping the nut from being able to reach the thread on the valve. Do I need another kind/size of olive?

2 - Should I be applying some kind of jointing compound or PTFE tape when putting the new valve on?

3 - Anything else I should be aware of? I'm hoping that the fact that there is already a 15mm Myson valve on the rad means that it should just be a fairly simple swap job but I know the current leaking one is probably about 18 years old so the spec might be slightly different.

PS the system will be fully drained down when I'm doing this.

 

[PrenticeBoyofDerry]

Can you either link or upload pictures of what you have purchased for this task?

You possibly been better purchasing an internal reducer, that fits inside the TRV.

This 15mm x 10mm compression internal reducer from Evolve is designed for use with 15mm compression fittings such as radiator valves, tees, couplers, elbows etc. It works by replacing the olive inside a 15mm compression fitting or radiator valve and reducing it down for use with 10mm pipe.

 

[b0ng0]

Thanks for the reply. I have bought the following:

Myson 2-Way TRV
http://www.heatingcontrolsonline.co...ves-c-28_37.html/myson-trv-way-trv-p-362.html

15-10mm Reducer
http://www.heatingcontrolsonline.co...s-c-28_37.html/15mm-x-10mm-reducer-p-226.html

I also have some PTFE tape and jointing compound.

 

[TeaTime]

The reducer just replaces the position of the 15mm olive.

 

[Agile]

Should be a simple job.

May be better to clean the tube with wire wool or emery paper before you fit it.

Better to keep existing water in the other rads by turning off the valves rather than draining everything.

Tony