Thermostatic radiator valve

[TMC]

Just popped into bedroom it was very warm in there

Much too warm in fact

Thermostatic valve head had parted company from body

Its an ECA brand which I can get from ebay (the body looks the same but the head slightly different)

My question is would head of a different brand fit and work as toolstation is nearby

The ECA one has the female threaded ring on the head and the male thread on the body

Regards

[Roger Mills]

I don't think there's a standard to which they all adhere - so it's unlikely that a different sort will work properly. It may physically fit

- because there is a limited range of threads used by different manufacturers - but that doesn't mean that the temperature control will be correct because the bit which contacts the valve's pin may not be in the same vertical position.

I have a feeling that Drayton had used to calibrate their heads against individual valves - so that if you swapped heads between two seemingly identical valves, they might not then work the same.

[Lobster]

Spookily enough I found the same problem this morning in the spare room

- although the TRV was turened right down to 'off' the radiator was very warm. Certainly not down to frost protection or anything like that - nowhere near cold enough - and the head is definitely correctly and firmly fitted.

I thought TRVs only failed in the other direction, ie staying cold because the push-rod inside gets stuck. What's going on with mine?

David

[Dave Liquorice]

They tend to get stuck closed after the summer when they have been forced closed by hot rooms.

Have you taken the head off yours and made sure the pin moves freely? Friday I looked at one of our radiators that was also far hotter than it should be, pin stuck in the up position, freed it but have been away so don't know if it's cured it...

[Lobster]

Yep, aware of that but not come across it the other way round

Yes, it was completely free; the head is in good shape (it's a not particularly old Honeywell TRV) and there's no slop anywhere. Can water still get throught the valve with the pin fully 'down'? I suppose the acid test would be to figure out a way of visibly holding the pin fully 'down' without involving the head - might be able to balance a large rock on it or something...

David

[Dave Liquorice]

You no longer have the service cap that would have been supplied with the valve?

[Lobster]

Ooh - lightbulb moment! Why didn't that occur to me?

Simple answer is 'probably' somewhere - one of many different ones for different TRVs. Will have a root around sometime. Meanwhile pending investigation I've got the rad (spare room) isolated via the lockshield valve, so cold be a round tuit job...

David