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TRV Continuously Shutting Radiator Off

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Hello,


Sorry for the long post, but I think detailed information will help you in providing maximum input!


I live in a 3 bedroom, 2 floor (Ground, 1[SUP]st[/SUP], 2[SUP]nd[/SUP]) end terraced house, with 7 Gas Radiators in the property. The house is 30 years old.

Previously we had an old system where there was no separate control for Heating and Hot Water; so whenever the boiler was turned on, it used to heat up the water and the gas radiators at the same time.

That boiler was a Micron Glow-Worm 50FF, which we had for over 10 years.
All the Radiators had TRVs on them, and they used to work perfectly well. The property did not have a Room Thermostat though.

Recently (beginning of last week), we had a brand new Baxi 18HE A Boiler installed, along with 3 x radiators (the 3 being replaced were old and had pin holes in them), and new pipe work ( 2 primaries), which meant that Heating and Hot Water could be separated, and they could be controlled separately, on behalf of an Energy company by subcontractors, as part of the Government’s ECO legislation.

So the new system we have now is a Y Plan Sealed system (although with the old system we had an Expansion Vessel up in the loft).
The water and heating has been absolutely fine and we have familiarised ourselves with the new system without any problems, including the Room Thermostat.

Just to clarify please, the problem we are having is not related to the Room Thermostat, the Settings of the Digital Programmer etc, or our lack of understanding of the Room Thermostat, Thermostatic Radiator Valves or anything else.


2 out of the 3 new radiators are working fine as are the other 4 (old) radiators.
However ,there is a problem with one radiator (TRV), which was newly installed. The TRV on the radiator was brand new too.

When this radiator was turned on, just like the other radiators it came on and got warm, but used to then shut off permanently, without coming back on, while the other radiators continued to stay on throughout.


This particular radiator after reaching a certain temperature/warmth, just shut off and stayed off; even for hours without coming back on, while the Heating was still On and the other radiators remained on and remained warm.
If the TRV head is removed from this Radiator and Heating turned on, the radiator remains. I recently monitored it closely and kept the Heating on for a continuous 18 hours, and this radiator, without TRV head on, remained on and hot for this whole time.

When the Engineers that carried the work returned to our house they were baffled, saying a radiator should either come on or it shouldn’t, and to go off after a while (within 30 mins or so) after coming on didn’t make sense. They also realised that none of the other radiators were doing this, and only this particular radiator was showing this fault.

They changed the TRV Head and screwed it on loosely (which I later realised), making it appear that everything was working fine as the radiator stayed on constantly and didn’t shut off. But after I turned the TRV Head on and off, it came off, due to not being securely screwed on.

So, if the TRV Head is left off the radiator completely, the radiator stays on constantly as soon as the Heating is switched on. If the TRV Head is put on loosely – when you can just about turn it on and off before it would eventually fall off – the radiator would stay on.

I lost confidence in the Engineers that carried out the work, as I found their conduct unprofessional throughout and felt they lacked integrity, especially as they showed little consideration about the fact that I had an elderly and disabled mother in the house.

I invited a friend of mine, who is Gas Safety Registered, to have a look at it, and we both agreed to begin with (I was especially keen to get some clarity and eliminate as many “possible” causes as there may be for this) that it would be a good idea to replace the whole TRV – TRV Head & TRV Body.

I wanted a brand new Danfoss TRV. After draining the radiator etc, he fitted the Danfoss TRV onto this radiator.

It soon became apparent that the radiator with the new Danfoss TRV on it was doing the exact same thing as before – it would come on, and after reaching a warm temperature, it would just shut off and stay off within 30 minutes of being turned on (less really), while the other radiators remained on and remained warm. So, the original (brand new) TVR Head & Body that were fitted to the new radiator in the firt place weren't faulty.

Just want to point out that this radiator in question is on the first floor, just above the Boiler on the ground floor kitchen.

My friend said that he had never come across anything like this.

His “theory” was that the pipes for this radiator were getting particularly hot and so was the radiator, quite quickly due to being directly above the boiler. He said that the Thermostatic Head was obviously “sensing” this temperature, finding it exceedingly hot and shutting the radiator off. He reduced the Heating temperature on the boiler and restricted (closed it quite a bit) the lockshield valve on the opposite side to the TRV. Neither of these things made a difference.


As quite an experienced and well respected Gas Engineer (Gas Safety Registered), he had never come across a situation like this and was at bit of a loss. His final suggestions were to consider replacing it with a Half Turn Valve (non thermostatic), as that will come on and off whenever we want and not be like the current one because of different technology.


His second suggestion was to move the TRV to the other side of the radiator, where the Lockshield is, and switch them around, in relation to something “technical” to do with the return pipe, but there is no guarantee this would work.


Hope you are still with me and I haven’t exhausted you by waffling too much!
*Does anyone know what is going on and why?
*Are the 2 options my friend suggested the only ones available to me?


I’ve been getting quite stressed about everything, which has upset my vulnerable mum too.


Thank you.

:smile5:
 
Thank you for all your help guys!

I will take everything on board.

I just wanted to ask for my own reference- if we didn't
get anyone to rectify this fault and left things as they are,
apart from the inconvenience, could this cause any long term
problems or damage to the system if we leave things as they are?
 
To clarify, when we wake up first thing in the morning and the Heating/Boiler is off and all radiators TRVs are off, and when the Heating is turned On we only want this particular Bedroom radiator or Hallway radiator to be On.
The radiators will have cooled down overnight, but that doesn't mean they are off. If the TRV has not been touched, i.e turned down to the lowest setting, the room will warm up, when the heating is turned on, until it reaches the temperature set on the TRV.
 
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