TRVs - do they work?

[WillB77]

Fitted all the rads with £7 jobbies but not convinced they work, I'm guessing you get what you pay for.

But why would I need a room thermostat as well as TRVs?

Does the room stat determine the overall output of the boiler for the whole system and then you use TRVs to fine tune this on a room by room basis?

 

[leakydave]

That's about it. TRV's regulate heat to where it is needed. Ideally no TRV fitted near wall stat, just a balanced radiator with 2 lockshields. A TRV near wall stat might close and the room may never reach the required temp set on wall stat.
What make of TRV did you buy?

 

[WillB77]

They're Drayton. ANything above 3 the rads get hot, below that they tend to be cold with little difference above / below either setting

 

[JohnD]

A TRV prevents the temperature of the room getting too hot and wasting heat. It also can prevent the room getting too cold (if the CH is running) and so uncomfortable.

The room stat stops the CH running (and wasting heat) once the whole home is warm enough. So the room with the wall stat should not have a TRV as they woud be in conflict, and the lockshield should be turned down so that room warms up slower than all the others.

p.s.
if you turn them to "just below" 3, where they seem to be shut, and wait, you will find the room cools down tonight (it is cold outside). When the room cools, the TRVs will open and stop it getting colder.

If you turn them to "just above" 3 where they are just starting to open, and put the heating on, you will find the room warms up. As it gets warmer they will close and prevent it getting too hot. From cold, it might take an hour to reach temp.

the further from "3" you set them the more noticable it will be.

I find "about 3" is about right, but the bathroom is set to 4 which is quite warm. The spare rooms are set to 1 or 2 which is quite cool.

 

[big-all]

They're Drayton. ANything above 3 the rads get hot, below that they tend to be cold with little difference above / below either setting

thats the way they work the numbers relate to temperature
on mines 1=12 2= 16 3= 20 4= 24 5=28 6 =32 degrees

so if yours are the same its telling you the room is at 20 degrees so above that you get full heat untill it reaches temperature below that no heat required

 

[libby lou lou]

Didn't know that no. 3 was about 20, which is about right, thanks for the last two posts.

Can sort mine out now.

 

[WillB77]

Am i right in thinking that I don't need to worry about balancing if i have TRVs?

 

[spacethegas]

no.

 

[Gasguru]

You must balance the rads for the system to warm up evenly and all rads to get hot.

 

[Paul Barker]

trv's are fine for twee houses which have a large radiator to heat loss ratio no drafts and good insulation.

In my house they serve no useful function whatsoever so I won't have them.

If I ever sell I will of course put a bunch of cheap ones on for that twit the government insist upon.

 

[D_Hailsham]

They're Drayton.

That's a reliable make. They make several models; which one do you have? The numbers mean different temperatures depending on the model!

The room stat turn the boiler off when the room reaches temperature. Without a room stat, the boiler would just keep running, even if all the TRVs have closed down. This wastes gas. As JohnD said, you need to make sure the wall stat does not turn the boiler off before the TRVs have worked.

A correctly balanced system is essential for TRVs to work properly. Balancing TRVs is Drayton's recommended method. The only thing many would disagree about is the use of the "decorators cap" to hold the TRV partly open. The general consensus (Danfoss, Honeywell) is that a rad should be balanced with the head off the TRV.

 

[Norcon]

trv's are fine for twee houses which have a large radiator to heat loss ratio no drafts and good insulation.

In my house they serve no useful function whatsoever so I won't have them.

If I ever sell I will of course put a bunch of cheap ones on for that twit the government insist upon.

If your radiators are sized correctly then a comfortable temperature should be acheived in your home at an outside temperature of say -2c.
What happens when the outside temp is 8c combined with solar and internal heat gains ?.
If the rads are sized correctly you should have a temperature overshoot taking place wasting fuel.
OK so you have a highly inaccurate wall stat or two located some where in your home interlocking the boiler.
But do you really think this can be set to avoid temperature overshoot throughout the home or shutting down the boiler when some rooms are still cold.
I needn't preach though. I have no trv's fitted to the rads in my home.