Do TRVs work?

[Multiplex]

Just moved into a new house with an unvented pressurised system.

All the rads are fitted with Drayton TRV 4's, except the one in the hallway which is left open.

I've never lived with TRVs before. How do they work? I thought they monitored the room temperature to control the flow of water through the radiator? But someone else said that maybe they just control the temperature of the radiator - i.e. not by what temperature the room actually is.

My problem is that the rads don't come on at all when the TRV is set to 1, 2 or 3. But at 4 it's warm, and then at 5 it's hot.

But downstairs the small rad in the bathroom will be boiling hot when the TRV is set to 2.

Even when the room is ice cold in the morning and the TRV is set to 3 on all the other rads they never heat up.

Is this how it's supposed to work? My pressure is at 1.5 bar so I can't see how there could be a problem??

Simon.

 

[JerryD]

trv's monitor the temperature immediately around themselves. Only certain types monitor the room temperature and these have a wall stat linked to the trv to control it. Yours sound like the normal type. Trv's can take about 15 minutes to respond to temperature change sometimes (depending if gas filled or wax filled).

You c/h system may need balancing, the whole system needs to be nicely balanced first before tweaking any trv's.

Have you balanced your c/h and if not, do you know how to do this?

 

[masona]

Tvr's sense the air temperature in the room. The pin inside the head do sometime get stuck, take it apart and give it a service and see if there is a movement on the pin.

 

[Multiplex]

I'll have a look into how to balance the system. But given it's a brand new house and a brand new system I was hoping it would all be working.

Somehow I thought that the use of TRVs meant that balancing the system was less important though.

What I can't understand is that, if the room is ice cold and the heating is supposed to be on, then the TRV on setting 3 should allow the radiator to become fully hot before reducing the water flow as the temperature increases. If that doesn't happen (it doesn't seem to happen here) I'd like to know why.

And I'd like to know why six other TRVs in the house all behave in the same strange way.

As I said I've not had them before, I was kind of hoping that I could put them all on 3 and let them keep the room temperature constant, instead of me adjusting them all the time.

Simon.

 

[kevplumb]

if its a new house get on to the builders

 

[HandyJon]

... given it's a brand new house and a brand new system I was hoping it would all be working.

From my experience that doesn't mean much. A brand new house is likely to have a number of problems (mostly minor) because the builders are usually more interested in getting the house finished quickly than on getting it done right. A second hand house however will have had all the bugs ironed out of it, unless you've got an old house which has not been maintained properly. 5-50 year old houses are the best for not having many problems.

 

[div69]

I have noticed that some TRVs cannot be installed wherever, i.e. depending on flow/return pipes TRVs can go vertical or horisontal.
If you can go to a shop that sells your type of TRVs and have a look at the leaflet how they should be installed and which pipe is the 'flow' and which is the 'return', then you can workout if installed correctly.