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Discuss Towel Rail on Hot water system in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

Itsmeuknow

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Hi all
Hope you can help... firstly, I'm not a plumber, but l like to be hands on If possible and try to understand things if I can. The problem I have is I had a new radiator/towel rail replaced in my bathroom which I tiled a while back. I had a local plumber plumb the radiator in which I had purchased myself, it will only ever get hot when I bleed it other than that it will not get hot. The plumber is unable to be contacted, this is why I'm trying to sort it myself. The only thing he did was to put one pipe the other side of the wall for me, the only difference in the radiators is the old radiator had one connection on top and one on the bottom, the new radiator has both on the bottom, could this be the problem? Also, I believe this radiator runs off the hot water system, sorry if my terminology is not correct or I'm a bit vague. I have uploaded some pics, one of them I've tried to follow most of the pipe work to try and get an understanding of how the systems works. Thanks for reading this, would love to hear your thoughts or ideas to fix it.IMG_20190910_192002.jpg20170330_160712.jpg20170407_102326.jpg20170922_162948.jpgIMG_20190910_191659.jpg
 

Chuck

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My first guess would be an air lock in the 'horizontal' run through the roof space. It needs to have the correct gradiant (starting from the towel rail end and rising towards the tank end.

What setting is the pump on? If it is low, you may find that temporarily setting it to high is enough to shift the air around to somewhere it can be bled out.

What puzzles me is that the new pipework looks nicely done. (Decent soldering, bends rather that elbows, copper not plastic, etc.) Whoever did that would surely know how to avoid airlocks.
 
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Itsmeuknow

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My first guess would be an air lock in the 'horizontal' run through the roof space. It needs to have the correct gradiant (starting from the towel rail end and rising towards the tank end.

What setting is the pump on? If it is low, you may find that temporarily setting it to high is enough to shift the air around to somewhere it can be bled out.

What puzzles me is that the new pipework looks nicely done. (Decent soldering, bends rather that elbows, copper not plastic, etc.) Whoever did that would surely know how to avoid airlocks.
Hi chuck
Thanks for you time..
I check the gradient tomorrow in the loft tomorrow, thanks. Not sure about the pump. To be honest, didn't know it could be altered.. I'll check it out.. The soldering on the pipe work was done when system was built in the 70's, I have just cleaned it up when I was decorating.. Thanks again Chuck for your help.. So the difference in position of the radiator connections wouldn't make a difference?
 

Chalked

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The radiator is on the primary side of the heating. So it should work when either hot water, or heating is calling. It should still work, if it as you’ve drawn.
As above, could be an air lock if the pipe is at a high point before it drops Down to the rad.
Are both radiator valves on? Also could be over use of ptfe thread tape blocking a path on the rad.
 
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Itsmeuknow

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The radiator is on the primary side of the heating. So it should work when either hot water, or heating is calling. It should still work, if it as you’ve drawn.
As above, could be an air lock if the pipe is at a high point before it drops Down to the rad.
Are both radiator valves on? Also could be over use of ptfe thread tape blocking a path on the rad.
I'll check it out valves tomorrow also. Thanks so much for the info. Good to know the setup should work. Be nice if it's just an airlock.. I did open the top bleed valve on radiator and it heated up, once I closed the valve it went cold again.. I'll post tomorrow my findings.
Post automatically merged:

I'll check it out valves tomorrow also. Thanks so much for the info. Good to know the setup should work. Be nice if it's just an airlock.. I did open the top bleed valve on radiator and it heated up, once I closed the valve it went cold again.. I'll post tomorrow my findings.
Also the pump is on setting one. It only supplies three radiators as I live in a bungalow.. Will it be ok to turn it up?
Post automatically merged:

Hi Chuck
I had a look at the valves, all good. fully opened both. when I open the valve at the top of the radiator, hot water comes through but never stays hot. when the water is on I have done another pic to show what the pipes are doing. Also turned pump to speed 2, didn't help. The pipe in the loft does have a gradient. Any help would be appreciated.InkedIMG_20190910_192002_LI.jpg
 
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Itsmeuknow

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Hi all
Still no joy with this radiator, when the hot water or heating is on the picture above is all I get. Seems like the hot water doesn't want to flow to the rad. All that was changed was the radiator.
 

Ben-gee

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Could well be an airlock in the red pipe from loft to rad.

Back feed it using mains pressure then it should run ok.

Can you easily raise the expansion tank as this will help and make future problems less likely.
 
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Itsmeuknow

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Hi Ben
Back feed it using mains pressure then it should run ok.
How do I go about this? Sorry. I'm a novice... 😀 👍
Post automatically merged:

Also am I right in saying I have a fully vented gravity fed system?
Thanks in advance
Jamie
 
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Ben-gee

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Best to get a plumber for this, it’s quite simple but has potential to go tits up - then you need to not panic and know what you’re doing!
 

centralheatking

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It
Hi all
Hope you can help... firstly, I'm not a plumber, but l like to be hands on If possible and try to understand things if I can. The problem I have is I had a new radiator/towel rail replaced in my bathroom which I tiled a while back. I had a local plumber plumb the radiator in which I had purchased myself, it will only ever get hot when I bleed it other than that it will not get hot. The plumber is unable to be contacted, this is why I'm trying to sort it myself. The only thing he did was to put one pipe the other side of the wall for me, the only difference in the radiators is the old radiator had one connection on top and one on the bottom, the new radiator has both on the bottom, could this be the problem? Also, I believe this radiator runs off the hot water system, sorry if my terminology is not correct or I'm a bit vague. I have uploaded some pics, one of them I've tried to follow most of the pipe work to try and get an understanding of how the systems works. Thanks for reading this, would love to hear your thoughts or ideas to fix it.View attachment 40359View attachment 40360View attachment 40364View attachment 40362View attachment 40363
It all depends on how old your original heating system is. Back in the mists of time it was considered quite good practice to flow the hot water in gravity fed bathrooms through a radiator before the bath or basin taps...maybe its an old hangover. I will read the rest later only just picked this up....centralheatking
 

Dan1990

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I am not a plumber but I’d like to make a suggestion for clearing the suspected airlock. I assume the HW circuit is being used to test the towel rail and the end result is that water only circulates through the cylinder. I suggest using the CH circuit instead, but shutting off the other radiators to force water through the towel rail circuit.

The sequence would be:
  • Open both valves on towel rail
  • Close valves on all other radiators
  • Turn boiler thermostat to low
  • Turn off hot water circuit
  • Turn on heating circuit
  • Listen to pump to check it is circulating

If the problem is air then it should move out of the new pipe work. If there’s a blockage there will be no circulation so the boiler and pump will need to be turned off immediately to avoid damage.
 
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Itsmeuknow

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It all depends on how old your original heating system is. Back in the mists of time it was considered quite good practice to flow the hot water in gravity fed bathrooms through a radiator before the bath or basin taps...maybe its an old hangover. I will read the rest later only just picked this up....centralheatking
Thank you. Look forward to hearing from you...
 

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