Thermostatic valves dont adjust the temp

[bigfatal]

the majority of my radiators have thermostatic valves. Some of these work fine but some of them dont let you adjust the temp.

ie. Setting one or setting 5 makes no difference - the radiator is blazing hot. For small bedrooms this is pain cos the room just heats up too much.

we first discovered this in the smallest bedroom so I got a plumber to replace the valve, assuming that this was the problem. However, not change you can have off or hot but nothing in between.

Am I missing something, but isnt the whole point of them that you can adjust the temperature?! Any ideas about whats going wrong? (or are the valves just a con?!)

 

[John.g]

Mine work quite well, used EPH for the last few replacements, ensure the actuator is fully anticlockwise, max index, before attaching it, normally via a knurled nut that you hand tighten clockwise.
What make are yours.

 

[Ben-gee]

They don’t work like you seem to think.

The thermostatic valve senses the room temperature and when this has reached the desired temperature the valve shuts the radiator off.

Whilst the valve is open the radiator will get hot, according to the flow temperature setting on the boiler.

Turning the trv to a lower number doesn’t change the maximum temperature of the radiator, it just affects how long it will be hot for.

 

[John.g]

They don’t work like you seem to think.

The thermostatic valve senses the room temperature and when this has reached the desired temperature the valve shuts the radiator off.

Whilst the valve is open the radiator will get hot, according to the flow temperature setting on the boiler.

Turning the trv to a lower number doesn’t change the maximum temperature of the radiator, it just affects how long it will be hot for.

I think what the OP is saying is that the the TRV is, effectively remaing open, no matter what the setting, whatever ones views on how they operate, they should control the room temperature based roughly on the index settings, above.

 

[bigfatal]

Yes. I turn the rad on and it gets hot and stays hotm Even if you set it to 1, it doesn't cool down. It's in a small room which gets hot quickly so from what you're saying, it should get hot then the valve should shut off and the rad should cool down until the room temp drops.

It's not doing the shut off and cool down bit!

 

[John.g]

What make is the faulty one?.

If you remove the actuator after first turning it to max, push the valve pin in, it should move ~ 3 to 5mm and spring back out.

 

[bigfatal]

What make is the faulty one?.

If you remove the actuator after first turning it to max, push the valve pin in, it should move ~ 3 to 5mm and spring back out.

Will have to take a look when I get home

 

[bigfatal]

Will have to take a look when I get home

Hi again. Sorry for delay, have bee away from home.

The valve is from Pegler. It's now not even turning off when set to zero.

Sorry, I don't know the right names for stuff. I removed the plastic top (unscrewed collar beneath it and pulled it off). I can't see a pin, there is a hexagonak nut but the middle of it is just smooth / filled in. (I'm sure when I tried this with the old one there was a pin I tried tapping)

 

[Ben-gee]

Can you post a picture of the valve with the trv head removed?

 

[ericmark]

It does depend on the heads used, Mothers old house I used Energenie heads, and these show target and current so if the current exceeded the target I closed the lock shield valve a tad until current did not exceed target, and with her modulating gas boiler the rooms were spot on, but this house has oil so the boiler does not modulate so looking at the TRV report I get which shows how the room has done throughout the day, this is a Kasa head, the cheap (I paid £15 each in 2019) only shows what set to, not current temperature.

With mothers house when she died the new owners did not what electronic heads, so swapped back to mechanical, now the lock shield valves set, the old heads set at around 2.5 worked great, each electronic head has pros and cons, I find the Kasa (TP-Link) very good but it is not linked to any wall thermostat, I found a Tuya at £3.90 each, not a clue how good, the Kasa seems to have jumped in price at £55 I paid around £23 at the price now may as well get Hive or Wiser.

 

[Clockdoc]

Hi again. Sorry for delay, have bee away from home.

The valve is from Pegler. It's now not even turning off when set to zero.

Sorry, I don't know the right names for stuff. I removed the plastic top (unscrewed collar beneath it and pulled it off). I can't see a pin, there is a hexagonak nut but the middle of it is just smooth / filled in. (I'm sure when I tried this with the old one there was a pin I tried tapping)

The pin is in the part of the valve still attached to the radiator. You see it when the thermostatic head is removed. As others have said, it should be free to move in and spring out. They can get stuck open or closed and then turning the themostatic head will not adjust the valve. If the pin is stuck, you can often undo the central nut (some water may drip out when you do this so have a container ready) to get to the valve spindle and release it.

Also is the thermostatic head fitted and aligned correctly? There are usually some notches that need to line up and secure it in the right place. If not, the plunger inside the thermostatic head may not even contact the valve adjusting pin.

Hope this helps and good luck.