TRV's

rca779

Now I understand that a Thermostatic radiator valve controls the temperature of the radiator it is fitted to by restricting the flow of water.

However what I am really struggling with is how does this affect the rest of the house.

I have a VERY simple understanding of central heating, the boiler heats the water and it is pumped around the house. However if one of my radiators has a TRV set to 2 and therefore the TRV restricts the flow to this radiator, how will the next radiator, if it is set to 6, reach it's full heat?

Isn't the first TRV set to 2 is surely restricting the flow to the rest of the radiators?

Apologies if I am just being thick, but this is bugging me and a few colleagues I have asked don't know the answer.

Carrot007

All radiators connected in a line as you are thinking is very old fashioned and not used these days by anybody who knows what they are doing.

Nowadays each radiator is connected separately and can therefore operate independently.

There are some good diagrams on the net if you search for them.

rca779

My house was built in 1970 and I am sure that my radiators are all inline

Cardew

They cannot be in-line.


The TRV does NOT control the temperature of the radiator. The water temperature that flows through the CH circuit(i.e. all radiators) is set by the CH boiler.


The TRV senses the air temperature in the room and controls the flow of water through the radiator. So when the room reaches the temperature set(on the TRV) it shuts off the flow of hot water through that radiator.


If the radiators were connected 'in line' if any TRV was closed(shut off or reached temperature) then there would be no flow of hot water to any radiator in the house.

rca779

If the radiators were connected 'in line' if any TRV was closed(shut off or reached temperature) then there would be no flow of hot water to any radiator in the house.

Thanks Cardew, this is exactly what I was thinking and was the basis of my OP question.

So therefore each radiator must have a separate feed from the boiler - news to me :-)

Cardew

rca779 wrote: »

So therefore each radiator must have a separate feed from the boiler - news to me :-)

Not so!


Each radiator is like a 'spur' off the hot water feed from the boiler.


Difficult to describe without a drawing. Let is try this for an analogy.


If we take the M25 motorway(a circular motorway around London) and compare it to the main hot water feed. The M25 has, say, 20 service areas which we can compare to radiators. If a service area is open(TRV open) then traffic(hot water) can enter the area without affecting the M25 or any other service area.


If the service Area is closed(TRV shut) likewise the M25 and all other service areas are unaffected.


Edit
Another way of looking at it is an electricity 'ring main' in your house. You have lots of 13 amp sockets off that ring main. Compare each 13 amp socket to a radiator; it doesn't matter if that 13 amp socket is in use or not, it doesn't affect the other sockets.

Rubidium

rca779 wrote: »

So therefore each radiator must have a separate feed from the boiler - news to me :-)

The diagram in this post should make it clearer. Each radiator is connected to a flow pipe and a return pipe.

https://forums.moneysavingexpert.com/discussion/5441512