How can I get a Myson thermostatic radiator valve to work?

Tapping the pin worked okay on some valves together with spraying the pin with WD40 a few times whilst moving the pin in and out. The pin seems to get stuck over time with a bluey green material and this should be scraped away from the pin.
However there seems to be another problem. Some of the Myson plastic centre rods move up down as you turn the valve but some also seem to have springs and some of my valves with the spring on the rod and the counter spring on the steel pin seem to stop the valve working. I do not know how to fix the plastic part.

Kango 7
January 2013

Tapping the valve with a hammer worked for me, the pin popped up and bingo warm room thanks

Max David Sinclair
December 2012

The suggestion about tapping the pin cured our problem.A light tap was all that was needed.

carshalton
October 2010

If your Myson TRv 2 valve head is not working( i.e. the centre plastic control is broken) - the simple way to discover this is first align the black triangle and the completely black dot ( i.e. the full ON heating position)If then it is impossible to push the centre black button back flush with the centre "star" then the plastic centre control is broken ( this is a type of shock absorber internally). Anyway I have developed a very simple fix - this is important because the unit is now discontinued and if you need buy a replacement you will also have to buy a new 28mm TVR adaptor ( total cost for both at retail price £15.oo approx

To conclude - if you want the repair instructions for free send me an email to fund at eircom dot net

It's good to recycle and also save money!!

Sean O'Dwyer
January 2010

I would take off the top of the valve and you will see a pin that is pushed down. If you gently tap this with a hammer it will pop up. This will re open the valve. Now replace the top and your trv should now be working again.

Just a thought

Andy G
January 2007

I have Myson TRVs also and am having the same problem with a TRV on a bedroom radiator.

The plastic sensor in the valve is broken and cannot be repaired.

You have to turn the TRV to 0 and unscrew the top of the valve and replace it with one exactly the same. This saves you having to change the whole valve, which entails draining down the system.

I got the answer to this question on Screwfix under the plumbing section and DIYnot.com.

These are excellent sites for getting this sort of information

Alex Patterson
January 2007