Fitting 15mm TRV onto 1/2" Qual-pex

Dardania

Hi guys,

I am looking to upgrade the heating controls in my house to use TRVs, and have been recommended to use these: http://danfoss-randall.co.uk/xxTypex/286742_MNU17532454_SIT313.html

All of my radiators look old (80s/90s era) but the pipework seems more recent (house was refurb'd about 6 years ago) and I was able to note that it is Qual-pex 1/2". Am I safe enough to use 15mm TRVs with 1/2" qual-pex (apparently it's 14.7mm)? From reading a few past posts on this, there are two opinions that you can either use it stariaght away no problem, or you have to use a 1/2" olive inside...

Also, while I'm getting the valves changed out, I was considering anything else to do, and have in mind a magnafilter type thing, and a drain down valve. Anything else?

Thanks,

D

jack of all

I'm not a plumber but I have replaced standard rad valves with TRVs in my own house in the past. I just substituted the 15mm olives with 1/2" ones- otherwise you will have a leak. Hold onto the 15mm olives they'll come in handy if you ever need to replace your kitchen tap as most come with 15mm copper tails. When I did the job I flushed through each rad and added Fernox inhibitor to the tank when refilling.

gdavis

chances are there is already half inch olives on the qualplex and centres of new rad valves will be the same so u will be reusing nut and olive already on qualplex for new rad valves so problem solved !

Joey the lips

As its qualpex (Shudder) you will get a squeeze tight enough.

What i would do is put copper tails onto the TRV's into the wall so it looks a little professional (No disrespect ment) Then in this case you will just need to change the olive at the TRV copper part

gdavis

im hearing u joey but i was presuming op is a diy'er and repiping in copper may not be realistic.maybe the chrome /white wrap around covers may suit??

Outkast_IRE

I dont rate those danfoss valves at all, the thermostatic element works great, but i honestly think replacing the olives for 1/2" ones works ok .....but i find the slip for the copper pipe short in comparison to myson valves etc, also the myson ones will come with the correct olives etc.

The short slip on the copper pipe and using the 1/2" olives results in a joint which i rate as ok at best i say this from experience after fitting hundreds of danfoss and myson valves.

Personally i would buy the myson ones first.

Dardania

Thanks lads for all the comments. You're spot on about me being a diyer, and I'm a nervous one at plumbing at best! But the 1/2" olive sounds a right job for it...

I'm going to check out the myson ones also, as I'm wondering whether I should get a valve that I can replace the head one in case I want to go down the electronic route in further like with ecohome or equivalent

Dardania

Just to give a brief update on my progress, I bought the C2 TRVs with lockshields, and am fitting them presently. Work is going well, however slow, as I am having to learn all the basics of how to drain a heating system without a drain valve...

I bought this: http://www.abdtools.eu/p/product/0707015254-Radkit+Professional/ and used it to drain one rad with all the other rad valves closed, to then attach a drain connector to a hose to properly drain down the rest of the system. In retrospect, I don't know if I really needed the kit, but if nothing else, it gave me a sense of security that I could stop the flow from the first rad, and also that spanner that comes with it is spot on size wise...

With the olives, I reused the old ones so far, and it's generally working out. I did have a particular rad tail with an olive on it that I'm after pulling a bi too tight, causing it to bite into the qualpex, with a slight bulge, but no leak problems so far, having used PTFE tape...

Also, PTFE tape is great stuff!

As I mentioned in my original post, my house has a mix of rad sizes & valve sizes which is an absolute pain to work on...I'm trying to replace both rad valves on each rad to standardise, however I'm worried about splaying the legs out too far as the new TRV and it's associated lockshield seem to push out wider than th existing valves...tough one to get right.

My final act, when I have all the valves replaced is to use this universal cleaner: http://protex-solutions.com/dch.html which I'll introduce into the fill point. I already flushed water through for a good 20 minutes, but it seems that black sludge is tough to clear! Certainly it would make a mess of the carpets so plenty of towels are required...

Here's the drain point I introduced - tempted to get a length of qualpex to remvoe the joint which is as-built, however would require me to get a cuting tool: