Radiators on when they shouldn't be, but not all rads.

B0bbyEwing

Ok so it's flipping cold out so the fire is on. I don't know about where you are but it's in the 0c-1c range right now. As per usual when I put the fire on, I turn the downstairs radiators off (or to frost setting). Upstairs radiators are left on so that when the heating kicks in, upstairs gets some warmth but downstairs doesn't need the extra kick from the radiators since the fire is on.

So I was surprised it felt so warm when I went to get something from the fridge (pass a small rad on my way to it) - sure enough it's on, as is the bigger rad in the diner. 
I go in to the living room & the rad that is near the diner end of the living room is also on yet the big radiator at the far end of the living room is off & the small radiator in the hall by the front door is also off.

All were on frost setting (the star).

2 of those on were: https://www.toolstation.com/drayton-trv4-classic-thermostatic-radiator-valve/p55827
1 was: https://directheatingsupplies.co.uk/products/danfoss-ras-c2-15mm-straight-trv-radiator-valve-lockshield-013g600300-246134

The big radiator that is off is Danfoss type & the small one in the hall is Drayton so it's not linked to type of TRV.


Why is it running like this? Do I have 3 rads with faulty TRVs? Is it saying those 3 are needing to heat up because they're going to freeze? 

First time this has happened. They've always been off-off when on the frost setting.

ThisIsWeird

'frost' setting is around 5oC, I understand. You'd know if it was that cold - it surely isn't.

What else can allow a TRV to come on when it shouldn't? If the 'head' is loose - not screwed down fully. Or the head has failed in the open position. Or if the operating pin of the valve is seized in the 'up' position.

You can usually feel when the TRV starts to operate - it becomes more stuff to turn. Eg, at around 18oC (I think) it should feel loose when opened above '3', and become more obviously stiff to turn as you close it down below 3. How do yours feel?

Then you can try removing the heads, and checking the pin and head itself. For the pin, you should be able to push it down around 8mm-ish, (it's a strong spring, so use something firm over your thumb), it should bottom-out with a thunk, and it should pop back up instantly when released. It should be smooth in use 

For the head, look at the small round plastic part that presses on this pin - it should move in and out as you turn the head up and down.

(When removing and replacing heads, open it up to '5' first - makes it easier)

FFHillbilly

I'd buy a pack of these caps, fit them to the affected radiators and try the same thing tonight https://www.screwfix.com/p/drayton-radiator-valve-cap-white-5-pack/5649r

Apodemus

Is it possible that these rads are experiencing a cold draft?  With the fire on, you will be sucking huge quantities of air through the chimney, which has to come from somewhere and if that is outside air passing over the TRV, then the TRV may be experiencing a different temperature to normal.  If the affected rads are below windows and all the air from the chimney is coming from trickle vents, then this could easily be the cause.

We have an issue like this with our bathroom rad - with the extractor fan on, the draft from the hall is cold enough to keep the TRV open, even if the room is warm.

macman

Unless you have access to free wood or coal, why use an open fire? They are hopelessly inefficient, about 80% of the heat goes straight up the chimney.
Do you have main gas or oil/LPG CH?

B0bbyEwing

Bit of a development....

Turns out the smaller living room radiator was ON. Apologies on that front. Should've checked it myself but regardless, the issue persists because it's happening with one of the other radiators.

I can get all of them to behave EXCEPT for the small (Drayton TRV) rad near the fridge which even though the TRV is set to frost setting, the rad warms up real nice when the heating comes on. 

But here's the development....

It only heats up until a certain temp & then it turns off, yet the heating remains on (as in the display just inside the front door has the flame on it saying heating is on - and upstairs rads remain ON).

So for some reason it's coming on when it shouldn't (7pm), it'll heat to a certain point (let's call it 8pm for arguments sake), turn off while upstairs just simply come on at 7pm & go off at 9pm as scheduled.

Apodemus said:

With the fire on, you will be sucking huge quantities of air through the chimney, which has to come from somewhere and if that is outside air passing over the TRV, 

I wouldn't have thought outside air is passing over the TRVs. 

Doors are shut, windows are shut. The fire doesn't draw from the sub floor.

macman said:

Unless you have access to free wood or coal, why use an open fire? 

But who said I was using an open fire?

I never say to anyone I have an open fire because I don't.

And while I can't get free coal, I do get free wood.

theoretica

My TRVs are pretty easy to take off - I would swap the TRV with another radiator that has been turning off properly.  That would confirm if the issue is TRV or radiator.

BUFF

B0bbyEwing said:

Bit of a development....

Turns out the smaller living room radiator was ON. Apologies on that front. Should've checked it myself but regardless, the issue persists because it's happening with one of the other radiators.

I can get all of them to behave EXCEPT for the small (Drayton TRV) rad near the fridge which even though the TRV is set to frost setting, the rad warms up real nice when the heating comes on. 

But here's the development....

It only heats up until a certain temp & then it turns off, yet the heating remains on (as in the display just inside the front door has the flame on it saying heating is on - and upstairs rads remain ON).

So for some reason it's coming on when it shouldn't (7pm), it'll heat to a certain point (let's call it 8pm for arguments sake), turn off while upstairs just simply come on at 7pm & go off at 9pm as scheduled.

Sounds like the valve is stuck. take the sensor head off (whilst off check for any damage to that) & try pressing the pin in the valve (you will probably need a wider flat surface to press down)

diystarter7

theoretica said:

My TRVs are pretty easy to take off - I would swap the TRV with another radiator that has been turning off properly.  That would confirm if the issue is TRV or radiator.

You mean the top and not the body of the tvr as taking that off often means turning the rad and water off ie draing as well - we did ours quickly but its not "easy" - I think you have it confused with the top and not the whole thing
Thanks

macman

B0bbyEwing said:

Bit of a development....

Turns out the smaller living room radiator was ON. Apologies on that front. Should've checked it myself but regardless, the issue persists because it's happening with one of the other radiators.

I can get all of them to behave EXCEPT for the small (Drayton TRV) rad near the fridge which even though the TRV is set to frost setting, the rad warms up real nice when the heating comes on. 

But here's the development....

It only heats up until a certain temp & then it turns off, yet the heating remains on (as in the display just inside the front door has the flame on it saying heating is on - and upstairs rads remain ON).

So for some reason it's coming on when it shouldn't (7pm), it'll heat to a certain point (let's call it 8pm for arguments sake), turn off while upstairs just simply come on at 7pm & go off at 9pm as scheduled.

Apodemus said:

With the fire on, you will be sucking huge quantities of air through the chimney, which has to come from somewhere and if that is outside air passing over the TRV, 

I wouldn't have thought outside air is passing over the TRVs. 

Doors are shut, windows are shut. The fire doesn't draw from the sub floor.

macman said:

Unless you have access to free wood or coal, why use an open fire? 

But who said I was using an open fire?

I never say to anyone I have an open fire because I don't.

And while I can't get free coal, I do get free wood.

Your first post says 'Ok so it's flipping cold out so the fire is on'.
Which led me to believe you were referring to an open fire. If not a wood fire, what sort of fire are you referring to: a gas fire, an electric heater?

theoretica

macman said:

B0bbyEwing said:

Bit of a development....

Turns out the smaller living room radiator was ON. Apologies on that front. Should've checked it myself but regardless, the issue persists because it's happening with one of the other radiators.

I can get all of them to behave EXCEPT for the small (Drayton TRV) rad near the fridge which even though the TRV is set to frost setting, the rad warms up real nice when the heating comes on. 

But here's the development....

It only heats up until a certain temp & then it turns off, yet the heating remains on (as in the display just inside the front door has the flame on it saying heating is on - and upstairs rads remain ON).

So for some reason it's coming on when it shouldn't (7pm), it'll heat to a certain point (let's call it 8pm for arguments sake), turn off while upstairs just simply come on at 7pm & go off at 9pm as scheduled.

Apodemus said:

With the fire on, you will be sucking huge quantities of air through the chimney, which has to come from somewhere and if that is outside air passing over the TRV, 

I wouldn't have thought outside air is passing over the TRVs. 

Doors are shut, windows are shut. The fire doesn't draw from the sub floor.

macman said:

Unless you have access to free wood or coal, why use an open fire? 

But who said I was using an open fire?

I never say to anyone I have an open fire because I don't.

And while I can't get free coal, I do get free wood.

Your first post says 'Ok so it's flipping cold out so the fire is on'.
Which led me to believe you were referring to an open fire. If not a wood fire, what sort of fire are you referring to: a gas fire, an electric heater?

A (en)closed fire?