Drayton TRV4 question

[CPCUK]

Hi,

I purchased a new house recently which has central heating with a mixture of Drayton TRV3 and Drayton TRV4 valves. I thought I'd give the heating a good check for the colder weather approaching. Most of the valves were set to their frost setting so opened them to max. One or two radiators didn't get too hot so I removed the head and noticed the pins were only exposed by about 3mm. I checked others and it seems some might be up to around 8mm or anything in between.

If I press down a pin it definitely feels like when I release it, it is at its top limit.

I noticed there is a presetting tool available for balancing. Is this likely that this has been the case with my valves? By using this tool does this adjust the valve insert up or down the pin?

I closed the lock shield on each rad upstairs and then opened half a turn but now wonder if they should be left fully open if the TRV is acting as flow control.

Can anyone please shed a light in this.

Thank you

 

[D_Hailsham]

a mixture of Drayton TRV3 and Drayton TRV4 valves. ... I removed the head and noticed the pins were only exposed by about 3mm. I checked others and it seems some might be up to around 8mm or anything in between.

Is there any connection between the distance and version of valve, i.e all TRV3 are 3mm and TRV4 are 8mm?

If I press down a pin it definitely feels like when I release it, it is at its top limit.

The pin may not be attached to the part of the valve which actually stops the flow. so moving the pin may not be significant.

Does the pipe feel hot where it enters the valve? If so, the valve is stuck. Give the metal body a few taps with a hammer and it may free. If the pipe is not hot, you have a circulation problem

I noticed there is a presetting tool available for balancing. Is this likely that this has been the case with my valves? By using this tool does this adjust the valve insert up or down the pin?

Very unlikely. Most installers are not aware of this facility and if they are they wouldn't know how to adjust the valve. It adjust the flow by changing the size of an orifice, in the radiator connection, through which the water flows. Here's a pic showing the valve set to 3 on the black dial.

View media item 18380

I closed the lock shield on each rad upstairs and then opened half a turn but now wonder if they should be left fully open if the TRV is acting as flow control.

Balancing the valves when you have TRVs is essential. Leaving them unbalanced is the usual cause of complains about the valves not working correctly. Read the TRV4 Commissioning Guide and How to balance a CH system.

 

[Agile]

Earlier versions of Drayton TRVs were quite unreliable.

The TRV4 seems to have overcome the problems and is very reliable as well as being ( in theory ) bi-directional.

Generally my advice would be to replace all the earlier types.

Tony

 

[CPCUK]

Thanks for the replies!

The pipes do get hot at the valve and the radiators do get hot. I've checked 2 or 3 of the TRV3 valves and they do seen to vary in height (albeit not by a huge amount). Personally I think that although the valves are partially open I can't see how they can be 'fully open' seeing as the part in the head which presses against the valve pin moves much more from its min to max position.

Best thing is to renew I guess both the valve itself and as suggested remove the TRV3 heads for the TRV4.

I read somewhere that the newest TRV4 heads don't fit the older valves so need to check first. Does anyone know if this is correct please?

Cheers

 

[tonyo]

I have just had a look at a new TRV4 valve and the pin at 68 degrees protrudes about 9.25mm and will go down another 2 to 3mm when pressed.
There is a tool to balance the radiator using the TRV.

 

[CPCUK]

Tonyo

Thanks for looking at that. The valve pin height is more what I expected to see on mine. I'll have another look when I get home at my TRV4's.

So the valve doesn't actually move much at all then, correct? I was under the impression that it could potentially go the full 9mm up and down for example, ie, fully open to closed.

 

[tonyo]

I don't know very much about these valves, all I know is that a new one has around 9.25mm exposed and that if I compress it by around 2 to 3mm it closes the valve. The temperature I quoted in my last message was a red-herring.