Hot Radiators upstairs when heating turned off

[D_Hailsham]

The valve without a handle looks as if it could be an isolating valve; there are usually two - on either side of the pump - so the pump can be removed without draining down.

Here is a link to the User and Installation Manual

As others have said, you should not have a TRV on the radiator in the room with a thermostat. The reason for this is simple: if the TRV is set to shut down at a lower temperature than set on the wall stat, the wall stat will never reach the set temperature, so the boiler will never get turned off - this wastes gas; if the TRV is set to a higher temperature than the wall stat, the TRV will never work.

If you don't want to remove the TRV the simplest thing to is remove the thermostatic head. The valve will then stay permanently open and the room temperature will be controlled by the wall stat.

The draw back to this solution is that the room may heat up quicker than the rest of the house, so the boiler will turn of before the TRVs in the other rooms have worked. If this happens, the only solution is to replace the TRV where the wall stat is by a lockshield valve, which can then be closed slightly so the room does not heat up so quickly. Ideally, the TRVs should shut down the rads in the other rooms first; then the roomstat should shut the boiler down.

Incidentally, is all your house still using round pin plugs and sockets?

 

[Boatybob]

Ok so the system is not new! I had to remove the 3/4 inch nuts and fittings from the rads - not all were that easy. I really appreciate your comments re usage when the winter comes and will sort that out. However this should not cause the rads to heat up when the room thermostat is at it's lowest point and the CH is switched to off at the control unit. Once I have solved one, I will go to work on the other.
Thankyou to everyone for your help so far. Please dont give up on me.

 

[Boatybob]

Hi to you all.
I have read the manual and all the responses received yesterday and understand my problem much better. Thanks to you all for your help.
If the valve without a tap beneath the pump in my pics (updated today) is an isolation valve and not a gravity check valve, then it appears that there is no check valve as the pipes go direct into the floor.
//www.diynot.com/network/Boatybob/albums/
Can I replace this valve with a gravity check valve or a motorised valve such as the Honeywell V4043H and will this also act as an isolation valve for pump removal.
http://www.uk-plumbing.com/honeywell-2-port-zone-valve-v4043h-1106-28mm-p-1412.html
I am also in process of replacing the TRV in the room with the master thermostat with a lockshield valve.
Again thanks to all you experts - you give a great service.
Bob

 

[Soggy_weetabix]

Boaty,

Look and read this. Quite informative for someone like yourself

Dave

http://www.gasman.fsbusiness.co.uk/gravity_hot_water_pumped_heating.htm

 

[Richard C]

Hi to you all.
I have read the manual and all the responses received yesterday and understand my problem much better. Thanks to you all for your help.
If the valve without a tap beneath the pump in my pics (updated today) is an isolation valve and not a gravity check valve, then it appears that there is no check valve as the pipes go direct into the floor.
//www.diynot.com/network/Boatybob/albums/
Can I replace this valve with a gravity check valve or a motorised valve such as the Honeywell V4043H and will this also act as an isolation valve for pump removal.
http://www.uk-plumbing.com/honeywell-2-port-zone-valve-v4043h-1106-28mm-p-1412.html[/QUOTE]

That’s almost certainly just an isolation valve; that system looks even older than mine! The previous owners of our house fitted a new oil boiler about 5 years ago but left the rest of the system, basically, as it was installed in 1968! As a result, I’ve had to do a lot of work, replacing practically everything (all new rads, tanks etc) except the basic pipe runs; further complicated by rather old but still fairly efficient solar panel heating system. As I said previously, I also had the same problem with gravity circulation on the C/H circuit but the gravity hot water system had always worked really well so I decided to leave that alone & just update the rest of it. I wouldn’t bother with an anti-gravity valve, they tend to stick after a while; go for a 2 port motorised valve as you’ve indicated, linked into the pump circuit; unusual to be 28mm! It’s usually 22mm unless you’ve got massive pipe runs!

You should be OK to remove the TRV head on the rad in the room where the stat is; just regulate/balance the flow on the lockshield.

 

[Boatybob]

Thanks Richard
I removed the isolation valve this afternoon and proved what it is. It seems as if I am following your route but a little later - still my system is much much newer - about 1971, when the house was built. Thanks to everyone for your help - situation sorted until the next time.

With gratitude
Boatybob