Thermostatic valve

[andyv]

I've got a tall decorative radiator with 3 columns, called a Big One. It's got a Drayton TRV on the hot inlet side and a matching lock valve on the outlet.

It seems to me that when it starts up, the column nearest the TRV gets hot but before the rest of the rad has warmed up it's turned itself off. I've tried opening up the lock valve on the other end to get more flow through, but it's the same. The pump is running at its fastest setting.

Would it make better sense to have the TRV on the other end? What's the normal convention? The TRV has arrows on it indicating it will operate with the flow in either direction.

[James Salisbury]

You can get some TRVs with a remote vial

should help..

[Derek Geldard]

Maybe less is more. ;-) . You could try running with a lower flow rate and or a lower temperature.

Some radiators have a sparge pipe on the inlet end to distribute the incoming water along it's length.

Derek.

[Andrew Gabriel]

It sounds like the radiator is directly heating the TRV bulb, which is rather unusual. When I first used them, I was concerned this might be a problem, but it isn't as the valve head is very well thermally insulated from the valve base, and being at the bottom, it's in the cold draft of air being drawn in to the hot radiator.

Is there some reason why your towel rail would be directly heating the TRV?

What happens if you turn the TRV up to max?

[Man at B&Q]

A local microclimate covered by towels is the usual problem in our house.

MBQ

[Andrew Gabriel]

Ah yes - the old issue of a towel rail not being any good at heating when it's being used as a towel rail, but begs the question, why put a TRV on it? (That's also why I never fit heated towel rail for myself.)

Actually, I've confused the issue by calling it a towel rail. That's clearly not what the OP said, sorry.

[RobertL]

What happens if you open the TRV up to a higher setting?

Robert

[andyv]

Thanks folks. A bit more on this - it's not a towel rail as you've realised, just a fancy rad in my dining room.

I've had the TRV turned up full or so I thought but there appears to be some adjustment on the internal mechanism so I'll also try that.

If I take the control mechanism off the TRV, the radiator heats up fine, but not as intended by the maker.

However, and Derek seems to have put his finger on this, that the rad appears to be directional and the pipes are probably on the wrong way round. The plumbers who installed it seem to have not realised this. It's not all they got wrong. That and leaving the packaging and the remains of their lunch under the floor boards.