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New boiler, rads keep getting cold

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Discuss New boiler, rads keep getting cold in the Boilers area at Plumbers Forums

SJB060685 said:
One indication of large sludge build up in the system is to get a strong magnet and offer up to the copper pipework in several places. Copper cannot be magnetised but if there was magnetite (sludge) in the system the magnet would adhere to the copper.
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Update. Got the engineer back. He looked at the one that comes on gets very hot and then goes off and stays off . He said trv was stiff took it off wiggle pin. It heated up. Of course he went and it switched off again. Others still cooling off quickly and only get a bit warm again. I am having to keep the couple that do work on 5 to get them to stay on. House thermostat never reaches its max. So house not too hot. These as I said are new Tower Trvs . Now my old trvs never turned the rads completely off stayed on all the time at the output we set. He said new systems are different I just want to cry. Surely the rads shouldn't get that cold for that long. Any advice
 
No they shouldn't. Under normal working conditions the trv's will stay open until target room temperature is met, whereby they throttle in. Was the new boiler sized correctly? As in is it's rated output the same as previous boiler?
 
SJB060685 said:
No they shouldn't. Under normal working conditions the trv's will stay open until target room temperature is met, whereby they throttle in. Was the new boiler sized correctly? As in is it's rated output the same as previous boiler?
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It was supposed to be a Baxi 18. When he came he asked me what it was I dont know how to check what he fitted we just trusted them
 
So he made no note of previous boiler output or did any heat loss calculations? The problem you're experiencing with rooms never coming up to temperature can be caused by an undersized boiler but I still think you have something else going on. Even if the new boiler was undersized you would still reach a certain indoor temperature, the fact you say rads warm up then go cold for ages suggests something else is going on as well.
 
SJB060685 said:
So he made no note of previous boiler output or did any heat loss calculations? The problem you're experiencing with rooms never coming up to temperature can be caused by an undersized boiler but I still think you have something else going on. Even if the new boiler was undersized you would still reach a certain indoor temperature, the fact you say rads warm up then go cold for ages suggests something else is going on as well.
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I think your right. Funny it worked when he took trv off. I told him it would go off after a bit permanently but he had to rush off. The boiler warranty says baxi 418 so I guess it is the right size our gut feeling is the cheap Trvs. He said all new systems go off completely. Because my Husband is elderly and so am I and female. He wont believe us. When I pushed him on why the trvs completely go off till rad is cold, he said it is hard to explain. He is such a nice guy but we have spent thousands, we are not wealthy and it looks like we will have to get in a new plumber and start again. He honestly, just does not know why it happens. Is it possible for trvs to be too sensitive to temperature levels. We can't be the only ones to ever have this problem
 
If all the TRVs are opened fully to index 5 they should stay full open until they are sensing a (room) temperature of 30C, so definitely something clearly wrong, they do shut off fully at the set temperature and have a very small hysteresis of a a degree or two but are fairly slow acting so are nearly always passing some water, they shouldn't open/shut rapidly.
 

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Thank you so much this what we thought but our plumber said the new systems don't work like the old my 30 year old ones never went cold. Do you know if Tower trvs are any good. Our rooms are nowhere near 30 degrees
 
No, I'm afraid or thankful that I've never heard of them. I replaced all (8) my 10/12 year old assorted ones but mainly Myson over the summer with "cheap?", around £12, EPH ones, all working perfectly well.
 
Tower I believe are in the lower price bracket, and in my experience I would tend to stick with proven named brands such as Honeywel, Drayton, Pegler et al.

Are you able to remove the trv heads? If so, you could remove the ones where fitted and see how long they stay hot for and if the rads are indeed getting hot?
 
Undertrained said:
Tower I believe are in the lower price bracket, and in my experience I would tend to stick with proven named brands such as Honeywel, Drayton, Pegler et al.

Are you able to remove the trv heads? If so, you could remove the ones where fitted and see how long they stay hot for and if the rads are indeed getting hot?
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Just took trv head off rad immediately hot. Let's see if it stays hot. Thank you will update
 
Undertrained said:
Tower I believe are in the lower price bracket, and in my experience I would tend to stick with proven named brands such as Honeywel, Drayton, Pegler et al.

Are you able to remove the trv heads? If so, you could remove the ones where fitted and see how long they stay hot for and if the rads are indeed getting hot?
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and get some neighbor that has a hammer (no don't do that), get him to reverse it and us the handle to push the pin(s) in (they should then spring out but only move ~ 3 to 5mm)
 
Undertrained said:
Tower I believe are in the lower price bracket, and in my experience I would tend to stick with proven named brands such as Honeywel, Drayton, Pegler et al.

Are you able to remove the trv heads? If so, you could remove the ones where fitted and see how long they stay hot for and if the rads are indeed getting hot?
Click to expand...
Just did as you suggested immediately went hit. Now will see if it stays that way. Will update
 
Mrs Naylir said:
Just took trv head off rad immediately hot. Let's see if it stays hot. Thank you will update
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The head is normally held on with a knurled nut so the head should be fitted with it fully opened (index 5) then finger tighten the nut otherwise you are trying to push in the pin at the same time.
 
Undertrained said:
Tower I believe are in the lower price bracket, and in my experience I would tend to stick with proven named brands such as Honeywel, Drayton, Pegler et al.

Are you able to remove the trv heads? If so, you could remove the ones where fitted and see how long they stay hot for and if the rads are indeed getting hot?
Click to expand...
Thank you so much it stayed on. We have put the head back on nie. Wow that was tricky as it was very very hot without it. So can I assume that it is obviously the trvs.
 
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