Compression fitting trouble and rad pipe a wee bit short

[dormermike]

Hi

I've put a new TRV onto a downstairs rad, had to drain the entire system and now i've put it all back together and refilled, there is still a very slight weep (culminating in a very slow drip - 10ml overnight approx) from both the copper pipe compression fitting and the TRV body to rad compression fitting.

I have already nipped them up, but as the pipe is at a slight angle as it enters the compression fitting due to being a bit short, I think that might be part of the problem. Also the pipe only goes in as far as the olive (maybe protruding about 2mm or so).

Is it OK to keep nipping up until watertight?

Otherwise I guess i need to drain down system again, and then extend the pipe, which leads to my next question:

Is it OK to extend the copper rad pipe using a compression fitting? I was thinking of using an isolation valve. I realise it may not look the best, but I cant solder.

Any other suggestions very much appreciated!

Thanks
Mike

 

[leakydave]

Ideally you need copper going right into the fitting. It's prob going to be a case of drain down and extend pipe. Iso valve ok if you can live with it being there.

If you are feeling adventurous [and have a good pair of wellies] you could use a pipe freeze kit, but check water has stopped flowing BEFORE cutting the pipe.

 

[dormermike]

Thanks Leaky Dave!

Is there anything better I could use than a iso valve? I guess the chunky bit of an iso valve is the compression fitting itself, so I guess i would need to put it somewhere discrete. There is a box section coming down from the ceiling in the corner of the room, but that would mean replacing about 3 metres of copper pipe.

I was concerned isolation valve might not take the heat?

Thanks

 

[dormermike]

I nipped them up a bit more and seem ok at the moment...

 

[Whitespirit66]

Sometimes, a bit of Fernox LSX can seal a borderline compression joint. However, would be best to extend the pipe.

Compression is fine, but looks untidy. If you use Yorkshire solder ring fittings, the solder is already in the joint, and they are dead easy. Much neater.

Don't use isolation valves on heating, as they restrict the flow quite a bit, even if fully open. Just use a straight compression coupler.

 

[dormermike]

Thanks for the info, i'll give the yorkshire fitting a go - i have a burner here.
Cheers.

 

[barkie1]

you could PTFE the olive or a bit of boss white might sort ya little drip.