TRV removal and refitting

[borzio]

Hi guys, I've read the FAQs about removing the TRV and tapping the pin for a stuck valve, but need just a bit more info as my problem is slightly different.

I have a Danfoss TRV RAS-C2 Sensor with the white head and grey ring. The head does not reduce the temperature of the radiator when adjusted. (It is always on, no matter what setting on the TRV). I want to take the TRV off to either adjust it or test the pin depending on the advice here. I also presume it is taken off anti clockwise?

The grey ring is very tight and I'm a bit scared to force it without hearing that I should, and that I may need an adjustable to do it, as I have only tried it with hand pressure so far as I was scared of breaking any part of it.
Secondly, what should I check when the TRV is off? Was it wrongly put on and if so how should I do it, or should I just go straight to putting another TRV head on, and again the best way to do it?
Thanks all for your help

 

[footprints]

Try gripping it with bit of rubber one of those grippy sheets for getting the top of jars, a builders grippy glove or the marigolds from the kitchen.

If it does not shut off it may be the sensor is US but there is always the chance it has stuck in the up position, but I have never seen one do that.

If the pin pushes in and pops out again quite freely I would change the head.

Just the ring turns not the whole body by the way.

 

[borzio]

Thanks footprints, in the end I had to get an adjustable wrench on the grey ring, slight pressure and it could turn. I used the white section above the grey ring on the body of the head to undo it as far as it could go (without turning the top section with the numbers on).

The grey ring retracted easily into the white section of the head all the way, exposing the white part that fits on the metal body of the fitting. (sorry I don't know the technical names of these parts)

I still cannot pull the whole top of the head (including the grey ring) off, so would like to know should this twist off now or pull straight off?

I've put it back together having adjusted the top of the head to be at maximum (6) aligned with the mark on the body. I'll see later when the ch is on whether it now adjusts the temperature properly.
Any and all suggestions welcome.

 

[Madrab]

Judging by the MI, the sensor is just a pop off/pop on

Page 6 -
http://heating.danfoss.co.uk/PCMPDF/VD33B602_RAS_C2_2_pipe_keym_teamcent.pdf

 

[borzio]

Thanks Madrab for the link, on page 6 it shows the pop on which engages with 'click', presumably just pushing the whole head straight down, does that mean you pop off by pulling in reverse straight up, or by rocking first to one side to disengage the lip?

(you plumbers have probably done a thousand of these and do it successfully without thinking of the sequence, this poor amateur is trying to make sure he doesn't do more damage LOL)

 

[gigz]

Wind the grey bit up to the hilt, then just roll the head to 45 degrees and it'll pop off. Is there any browny greasy residue on the head/valve ? If so it could have lost the expandy stuff thats inside (see, even plumbers don't know all the techy terms )

 

[Madrab]

Wind the grey bit up to the hilt, then just roll the head to 45 degrees and it'll pop off. Is there any browny greasy residue on the head/valve ? If so it could have lost the expandy stuff thats inside (see, even plumbers don't know all the techy terms )

Yup, that's the one - Better idea here - http://heating.danfoss.co.uk/PCMPDF/RAS_C2_VDAVH302_X010368en.pdf - page 3

 

[borzio]

Thanks Gigz and Madrab, got the offending head off.....easy when you've done it once thank Gord.

There was no browny greasy **it (see I can do technical, LOL).

The pin in the fitting moves ok and turns the rad off so I guess the head is u/s. I'll get one from screwfix and replace it anyway and let you know.

 

[Madrab]

Do remember that TRV's are not all a universal fitting, typically you will need to get the same valve to make sure it fits.

 

[borzio]

All done now with a new head, thanks everyone for the help,

Madrab, thanks for the advice I wouldn't have known that. I took the old one with me and got the friendly bloke behind the counter to take pity on me and check it before I bought it.
Piece of cake to put back together and...voila...adjustable heat.

cheers all till next time