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Don’t ‘TRV’ (Trust a Radiator Valve!)

 
Thermostats, Volumisers, Buffer Tanks, TRVs, Pumps, Piping, Valves, Radiators & Controls
Last Post by Toodles 2 years ago
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Toodles
 Toodles
(@toodles)
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Topic starter 23/11/2024 11:23 am   [#1889]

Not that I have really any hair to pull out but I was doing it metaphorically anyway!

The last week or so, I noticed that the living room was not quite reaching the set temperature and the Homely node in the room confirmed this. This room is our reference for the Homely and the ‘fully open’ lockshield valve that every other radiator was referenced to.

Now I know we have had a few chilly days of late but I thought that the same heating settings worked very well last November and December when we experienced a few days at -7 and -8 degrees C.; the worst I saw was that the same room was perhaps 0.3 degrees below par until about 09:30 and then all was fine.

I spent many hours doubting and checking everything I could think of (including all that work I had carried out to finely balance the radiators to achieve 22.5 degrees C. throughout the house during the day) to try to ascertain the reason. I even played around with the secondary pump speed on the LLH. The strange thing was that the rest of the house was fine, if anything just a little warmer than required - then the light bulb (LED, natch, of course!) started to flicker then glow brightly!

The TRV that like all the others (except the programmed one in the bedroom) was ‘fully open’ and should not be any form of impedance, should it? Upon loosening and then removing the TRV [after first trying shutting it down and opening up again a few times to no avail] …. the radiator increased approx 5 degrees C. in temperature in minutes and the room temperature started to return to normal. 😊 That TRV is now sitting on top of the valve body but not tightened down, thus protecting valve pin and keeping it tidy too.

So…. don’t Trust a Radiator Valve!!! Regards, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
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JamesPa
 JamesPa
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Posts: 4919
23/11/2024 11:38 am  

Thats odd.  I have experienced a (Drayton TRV4) which is stuck open because a plastic insert inside the head about 4mm dia and 2mm thick had somehow fallen out.  I have also experienced TRVs stuck shut, because they have been left closed in the summer (a sharp tap with a hammer usually fixes that), but not your one.  Could what you are experiencing be a variant of the 'left closed in the summer' phenomenon.  


4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.


   
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Toodles
 Toodles
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Topic starter 23/11/2024 11:50 am  

@jamespa The TRV has been left fully open since the day of installation; as have almost all others. We have a Hive programmable TRV on our bedroom radiator which allows me to reduce temperature for sleeping time and then back to normal in time to rise at 07:00. I do remember having some old valves in the gas boiler days which would stick but I hadn’t for a moment imagine a newish modern TRV that is set fully open could cause such a problem. Regards, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
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cathodeRay
 cathodeRay
(@cathoderay)
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23/11/2024 12:56 pm  

@toodles - my TRVs do the same thing, when fully open and fully screwed into place, they partly close the valve. Shocking design. If I screw the valve on slowly and carefully I can feel the extra resistance as it starts to depress the pin. Like you, I have then only loosely filled for cosmetic reasons.


Midea 14kW (for now...) ASHP heating both building and DHW


   
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Toodles
 Toodles
(@toodles)
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Topic starter 23/11/2024 1:07 pm  

@cathoderay Very bad design indeed! Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
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cathodeRay
 cathodeRay
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23/11/2024 3:25 pm  

Posted by: @cathoderay
↑

Like you, I have then only loosely filled for cosmetic reasons.

I really should proof read comments before posting...


Midea 14kW (for now...) ASHP heating both building and DHW


   
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Toodles
 Toodles
(@toodles)
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Topic starter 23/11/2024 3:30 pm  

@cathoderay 🤣 Toodles


Toodles, heats his home with cold draughts and cooks food with magnets.


   
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