pejoli:
1. the TRV senses the temperature of the air in the room, not the temperature of the water in the radiator.
2. As the room air temperature rises to meet the temperature set on the TRV, the valve gradually closes. This restricts the flow through the radiator, and the amount of heat transferred to the room, until it closes.
3. The temperature of the water in the radiator, and hence its surface temperature, will only gradually decline as the valve closes, because the heat is being lost to the room. The temperature at the flow side of the radiator will remain virtually the same as the boiler flow temperature until the valve closes.
Thanks for the detailed response!
This is how I understood it, however, none of my TRVs ever seem to close, no matter what the air temperature of the room, and how far down I turn the head - unless I turn it all the way to '0'. For example, the stat is in the hallway which is a bit drafty, so always colder than the front room. yet if the air temp is 19 degrees there, and I run the heating. the front room radiator TRV is always open, even if it's set to '*', or even lower (which I thought would close if > 7 degrees or so). I've taken the stat into the front room (it's a Hive detachable one) - same result. And it's the same for all 12+ TRVs throughout the house (all the same bulldog make)
I wouldn't have thought that all the heads could be faulty - though they are probably 15+ years old - and the pins aren't jammed as I can turn them on/off mechanically by turning the heads, and push them in with my thumb (just about - a lot of muscle required, and I wouldn't be able to do it if they were pointy-er) - so I'm really confused.
Possible tangent, but I bought a cheapo electronic trv yesterday (too tight to spend £50 on a hive one!) - mainly so I could isolate the bedroom so the heating doesn't come on there until after 10pm, but also to see if it could rule out the faulty trv idea. Unfortunately it doesn't seem to work - I don't know if the mechanical resistance on the pins are too high for it, but it doesn't close them either after it's calibrated itself - and tried it on a couple of different radiators with same result. Don't know if that's an indicator of the problem here, or just quality control issues at screwfix
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Mine doesn't move at all tried small hammer and wd40 but no joy going to try large hammer next ha ha.
Could you post a picture of yours so I can see how high the pin should be, also have a theory based on some info id seem else were that maybe the pin is to short for the head, either due to wear or incorrect head type, that might explain why when you turn yours up past 1 its full on as the pin rises to far? Its only a guess to be honest but seen elsewhere a couple of people have put small magnets ontop to act as an extension and it solved the issue but that was a Hive thermostatic head, don't know if that helps?
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Thanks good to know I'm whacking the right thing and going in the right direction in trying to free the pin, was just concerned that it might not be a trv and that it wasn't a pin before I went yanking it with pliers to try and free it up
Mine doesn't move at all tried small hammer and wd40 but no joy going to try large hammer next ha ha.
Could you post a picture of yours so I can see how high the pin should be, also have a theory based on some info id seem else were that maybe the pin is to short for the head, either due to wear or incorrect head type, that might explain why when you turn yours up past 1 its full on as the pin rises to far? Its only a guess to be honest but seen elsewhere a couple of people have put small magnets ontop to act as an extension and it solved the issue but that was a Hive thermostatic head, don't know if that helps?
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Thanks good to know I'm whacking the right thing and going in the right direction in trying to free the pin, was just concerned that it might not be a trv and that it wasn't a pin before I went yanking it with pliers to try and free it up
Here's mine - with a usb
Mine doesn't move at all tried small hammer and wd40 but no joy going to try large hammer next ha ha.
Could you post a picture of yours so I can see how high the pin should be, also have a theory based on some info id seem else were that maybe the pin is to short for the head, either due to wear or incorrect head type, that might explain why when you turn yours up past 1 its full on as the pin rises to far? Its only a guess to be honest but seen elsewhere a couple of people have put small magnets ontop to act as an extension and it solved the issue but that was a Hive thermostatic head, don't know if that helps?
[automerge]1607428495[/automerge]
Thanks good to know I'm whacking the right thing and going in the right direction in trying to free the pin, was just concerned that it might not be a trv and that it wasn't a pin before I went yanking it with pliers to try and free it up
Here's mine, with a usb for scale
