Plastic pipe to TRV

[chad5k1]

Hi All
I'm connecting a new towel rail and am using this Danfoss TRV and lockshield:
http://www.screwfix.com/prods/43668/Plumbing/Radiator-Valves/Danfoss-Straight-TRV-Lockshield-Chrome

Trouble is that the lockshield is a 15mm compression joint and I can't get it to hold the plastic. I've used JG PEX 15mm and a JG pipe insert in the end but the pipe only pushes in about 3mm into the lockshield, which does not seem enough for a good grip. If I use PTFE wound round the olive and the thread will that help and be enough, or should I bite the bullet and use a copper tube in this section?

Thanks for any advice
Rich

 

[twgas]

try removing insert, put nut and olive onto pipe, replace insert, do up.

 

[chad5k1]

Yeah I've got the nut and olive on, then put the insert in, but the pipe doesn't fit far into the lockshield (it looks like the gap is only a few mm and most of that gets taken by the insert!).
I then nip it up tight, but it still very easy to pull the lockshield off the pipe (taking the nut, olive and pipe insert with it!)

 

[rssteve]

are you using the correct jg insert, they do a special for compression joints, also use a copper olive.

 

[chad5k1]

I have a copper olive, was not aware of the different insert, only one listed on www.screwfix.com
hmmmm......

 

[gremlin16]

Danfoss make Trv,s & Lsv specifically for plastic pipes

 

[rssteve]

go to the JG website, they have one with no outer olive that lets more of the pipe go into the compression nut.

 

[chad5k1]

Thanks for the tips. Had a look at the site, but was still not comfortable with the amount the pipe went into the valve. I've used copper instead and a bit of PTFE on the compression. We will see if it is ok, but it feels solid.

 

[mikej2005]

A bit late now, but if you use the correct insert then the plastic pipe should go as far into the TRV as the equivalent copper pipe. I did 7 radiators in my place in this way last year and haven't had a single leak yet.

These are the compression inserts : http://www.johnguest.com/part_spec.asp?s=TSM_S2

 

[chad5k1]

Yeah, I saw them this evening, but I didn't have them to hand and did have copper. It was also getting a bit cold and I wanted to turn the heating and hot water back on