One of Downstairs Radiators does not heat up!

[Fredy]

I C.H. system with a combi boiler. 4 rads on 1st floor,1 in the attic and 2 on ground floor heat up perfectly but 1 of 3 rads on the ground floor does not heat up. It gets warm across the upper 1/3 part after at least about an hour. 22mm return and flow pipes feed all of the mentioned radiators via 22mm x 10mm (metallic bronze) manifolds on first and ground floor. Hot water from the boiler gets to one side of the rad but does not flow back to the return pipe through it. I have done the following work to resolve the problem without any joy.
1. TRV & lockshield valves checked - found functional not seized,
2. suspected blockage in the radiator, return pipe to the manifold - rad
flushed and pipe checked but there was neither blockage in the rad nor
any sign of restriction in either pipe or in manifold - rad still cold,
3. air lock in the pipes and the the rad in question checked,
4. pump is checked, the whole system balanced, all of the upper floors
rads turned off - pump found running fine and no difference observed on the ground floor rads,
5. turned off all of the rads including ground floors except the one in
the question - No Joy! A mystery.
6. coupled TRV and lockshield valves using a 15mm pipe - Hot water
from flow side flows to the manifold at the return pipe.
I am planning to change replace 22mm x 10mm manifold to 22mm x 15mm manifold. Boiler is situated in the kitchen on ground floor. The above mentioned mysterious rad is in the living room i.e. nearest to the boiler. It is very mysterious problem. Any advice / suggestion from fellow forum members would be appreciated.

 

[Rob Foster]

I C.H. system with a combi boiler. 4 rads on 1st floor,1 in the attic and 2 on ground floor heat up perfectly but 1 of 3 rads on the ground floor does not heat up. It gets warm across the upper 1/3 part after at least about an hour. 22mm return and flow pipes feed all of the mentioned radiators via 22mm x 10mm (metallic bronze) manifolds on first and ground floor. Hot water from the boiler gets to one side of the rad but does not flow back to the return pipe through it. I have done the following work to resolve the problem without any joy.
1. TRV & lockshield valves checked - found functional not seized,
2. suspected blockage in the radiator, return pipe to the manifold - rad
flushed and pipe checked but there was neither blockage in the rad nor
any sign of restriction in either pipe or in manifold - rad still cold,
3. air lock in the pipes and the the rad in question checked,
4. pump is checked, the whole system balanced, all of the upper floors
rads turned off - pump found running fine and no difference observed on the ground floor rads,
5. turned off all of the rads including ground floors except the one in
the question - No Joy! A mystery.
6. coupled TRV and lockshield valves using a 15mm pipe - Hot water
from flow side flows to the manifold at the return pipe.
I am planning to change replace 22mm x 10mm manifold to 22mm x 15mm manifold. Boiler is situated in the kitchen on ground floor. The above mentioned mysterious rad is in the living room i.e. nearest to the boiler. It is very mysterious problem. Any advice / suggestion from fellow forum members would be appreciated.

This is a very good post, you have covered most of the bases. I think that this rad may be piped up wrong ie rtn to rtn or feed to feed so it’s only getting passing flow. It’s a good one and let us know how you get on

 

[Harvest Fields]

Has it ever worked properly and did you say that it worked properly when you piped the trv and rad valve together or not?

 

[Fredy]

This is a very good post, you have covered most of the bases. I think that this rad may be piped up wrong ie rtn to rtn or feed to feed so it’s only getting passing flow. It’s a good one and let us know how you get on

Thanks Rob for your comments. It is connected properly i.e. flow to TRV and return to the other side. It is beyond my understanding. I have used all of my theoretical knowledge and practical/observatory skill to eradicate any possible fault. Therefore I have named it “Mystery”

 

[Harvest Fields]

Has it ever worked properly

 

[Fredy]

Hello Harvest Thanks for your interest.
I purchesed this house recently. This problem existed as the C.H. turned on. There was a very long over 2000mm x 600mm double rad was fitted originally. It covered almost one of longitudinal wall of the room. I intended to replace it with a smaller one even it would have n’t any problem. The original rad was checked and flushed as described in my previous post.
The rad in question is connected to the same flow and return manifolds where the other 2 perfectly working rads are connected.

 

[Fredy]

Has it ever worked properly and did you say that it worked properly when you piped the trv and rad valve together or not?

Hi Harvest, The hit water circulated from TRV to lock shield valve to Return manifold through 15mm pipe. I eliminated the rad by removing it.

 

[Harvest Fields]

Hi Harvest, The hit water circulated from TRV to lock shield valve to Return manifold through 15mm pipe. I eliminated the rad by removing it.

Surely this a rad issue then if when it was bridged it worked properly

 

[Rob Foster]

Simple maybe is the trv jammed down take head off and give the pin a sharp wack with a ball peen hammer

 

[townfanjon]

Rule the rad out 100% by taking it off and just put a piece of copper inbetween the two valves and see if you get circulation.

 

[Fredy]

Simple maybe is the trv jammed down take head off and give the pin a sharp wack with a ball peen hammer

The TRV is neither jammed nor sticking. Pin moves smoothly with a minimum pressure. I have got a new TRV when I replaced the rad. The old TRV was also not stuck in closed position.

Rule the rad out 100% by taking it off and just put a piece of copper inbetween the two valves and see if you get circulation.

Hi Townfanjon
Yes I have coupled both valves with a 15mm pipe. The water flew through satisfactorily. After this test I concluded a “Defective” radiator and replaced it with a new rad with new valves but the problem remained unresolved!

 

[Rob Foster]

The TRV is neither jammed nor sticking. Pin moves smoothly with a minimum pressure. I have got a new TRV when I replaced the rad. The old TRV was also not stuck in closed position.

Hi Townfanjon
Yes I have coupled both valves with a 15mm pipe. The water flew through satisfactorily. After this test I concluded a “Defective” radiator and replaced it with a new rad with new valves but the problem remained unresolved!

where are you ? if u are less than 20 mins off m5 junctions 1-6 m6 21 -8 - m1 south of catford interchange (a14) to london then AND NOT FRIDAY AS ITS POETS DAY MAKE a brew and who knows we could darken your door -- southbound 0700am northbound whenever - we still (yawn) are men in vans. not me they are but i could tag along get dropped off and they would gey me on way back from where ever your call CHKing

 

[Fredy]

where are you ? if u are less than 20 mins off m5 junctions 1-6 m6 21 -8 - m1 south of catford interchange (a14) to london then AND NOT FRIDAY AS ITS POETS DAY MAKE a brew and who knows we could darken your door -- southbound 0700am northbound whenever - we still (yawn) are men in vans. not me they are but i could tag along get dropped off and they would gey me on way back from where ever your call CHKing

Thanks mate for an offer but I am over 100 miles to north of the country.

 

[Best]

You might be getting very slow flow through the pipes.
You say when you opened valves - water flowed ok, and when you joined the valves with a piece of pipe then the pipe heated from flow to return.
But this could indicate a faulty rad valve on the return. The works of the valve might be pushing down when flow goes towards return, perhaps almost tightly off.
I have seen this only occasionally. Worth a try

 

[Fredy]

You might be getting very slow flow through the pipes.
You say when you opened valves - water flowed ok, and when you joined the valves with a piece of pipe then the pipe heated from flow to return.
But this could indicate a faulty rad valve on the return. The works of the valve might be pushing down when flow goes towards return, perhaps almost tightly off.
I have seen this only occasionally. Worth a try

Yes water travelled from TRV to LSV via 15 mm bridging pipe instantly.
Your observation does make sense but it confuses me to question

You might be getting very slow flow through the pipes.
You say when you opened valves - water flowed ok, and when you joined the valves with a piece of pipe then the pipe heated from flow to return.
But this could indicate a faulty rad valve on the return. The works of the valve might be pushing down when flow goes towards return, perhaps almost tightly off.
I have seen this only occasionally. Worth a try

You might be getting very slow flow through the pipes.
You say when you opened valves - water flowed ok, and when you joined the valves with a piece of pipe then the pipe heated from flow to return.
But this could indicate a faulty rad valve on the return. The works of the valve might be pushing down when flow goes towards return, perhaps almost tightly off.
I have seen this only occasionally. Worth a try

You might be getting very slow flow through the pipes.
You say when you opened valves - water flowed ok, and when you joined the valves with a piece of pipe then the pipe heated from flow to return.
But this could indicate a faulty rad valve on the return. The works of the valve might be pushing down when flow goes towards return, perhaps almost tightly off.
I have seen this only occasionally. Worth a try

Thank you for your reply and I appreciate your contribution in order to help me. It does make sense what you say but I am confused why did both valves work when linked up by a 15 mm pipe? Please note that the both valves are connected to flow and return 22mm pipes with the 10mm pipes.
As you said worth trying. Although both valves are new but there might be unexpected defect present causing the problem. I am intending to feed the rad using 15 mm tube and at the same time I will check the valves too and I will keep you posted

You might be getting very slow flow through the pipes.
You say when you opened valves - water flowed ok, and when you joined the valves with a piece of pipe then the pipe heated from flow to return.
But this could indicate a faulty rad valve on the return. The works of the valve might be pushing down when flow goes towards return, perhaps almost tightly off.
I have seen this only occasionally. Worth a try

 

[Rob Foster]

Yes water travelled from TRV to LSV via 15 mm bridging pipe instantly.
Your observation does make sense but it confuses me to question



Thank you for your reply and I appreciate your contribution in order to help me. It does make sense what you say but I am confused why did both valves work when linked up by a 15 mm pipe? Please note that the both valves are connected to flow and return 22mm pipes with the 10mm pipes.
As you said worth trying. Although both valves are new but there might be unexpected defect present causing the problem. I am intending to feed the rad using 15 mm tube and at the same time I will check the valves too and I will keep you posted

I would put my money on Freddy, change the valves for non trv cheapest wheelhead see if problem solved and then put fancy valves on

 

[Best]

Yes water travelled from TRV to LSV via 15 mm bridging pipe instantly.
Your observation does make sense but it confuses me to question



Thank you for your reply and I appreciate your contribution in order to help me. It does make sense what you say but I am confused why did both valves work when linked up by a 15 mm pipe? Please note that the both valves are connected to flow and return 22mm pipes with the 10mm pipes.
As you said worth trying. Although both valves are new but there might be unexpected defect present causing the problem. I am intending to feed the rad using 15 mm tube and at the same time I will check the valves too and I will keep you posted

Where I have come across faulty rad valves on the return, they had completely stopped the flow.
But it might be possible your valve is pushing down inside nearly tight off and this would explain why the test pipe connected between valves heats. It only needs a pin hole of flow to heat the small section of pipe.
But when the radiator is connected the small heat flow will just be absorbed

 

[Fredy]

Where I have come across faulty rad valves on the return, they had completely stopped the flow.
But it might be possible your valve is pushing down inside nearly tight off and this would explain why the test pipe connected between valves heats. It only needs a pin hole of flow to heat the small section of pipe.
But when the radiator is connected the small heat flow will just be absorbed

Thank you for explaining. As I have already mentioned I intend to replace 10mm by 15mm pipes for the radiator at my earliest convenience hoping that it would resolve the issue. I’ll let you know about the outcome definitely.

 

[Rob Foster]

Thank you for explaining. As I have already mentioned I intend to replace 10mm by 15mm pipes for the radiator at my earliest convenience hoping that it would resolve the issue. I’ll let you know about the outcome definitely.

where one gets a lazy radiator a shower power booster is idea for getting enhanced performance. AND NO I did not invent it ! my friend did

 

[Fredy]

Where I have come across faulty rad valves on the return, they had completely stopped the flow.
But it might be possible your valve is pushing down inside nearly tight off and this would explain why the test pipe connected between valves heats. It only needs a pin hole of flow to heat the small section of pipe.
But when the radiator is connected the small heat flow will just be absorbed

I am thankful to all of the fellow forum members who made efforts to help me to resolve my “Mystrious” problem. I am grateful to BEST whose advice resolved the mystery.
As I have mentioned earlier I have introduced 15mm pipes to the rad and replaced its LSV now.
I am glad to let you know that the rad heats up uniformly now. The conclusion is a faulty LSV (a new valve must be with manufacturing defect) which is beirher expected nor suspected with a new one.

 

[Fredy]

I am thankful to all of the fellow forum members who made efforts to help me to resolve my “Mystrious” problem. I am grateful to BEST whose advice resolved the mystery.
As I have mentioned earlier I have introduced 15mm pipes to the rad and replaced its LSV now.
I am glad to let you know that the rad heats up uniformly now. The conclusion is a faulty LSV (a new valve must be with manufacturing defect) which is beirher expected nor suspected with a new one.

In my previous post it’s concluding sentence was spell checked by by my smart phone resulted “beirher” instaed of “beirher”. Please accept my apology.

 

[Best]

I am thankful to all of the fellow forum members who made efforts to help me to resolve my “Mystrious” problem. I am grateful to BEST whose advice resolved the mystery.
As I have mentioned earlier I have introduced 15mm pipes to the rad and replaced its LSV now.
I am glad to let you know that the rad heats up uniformly now. The conclusion is a faulty LSV (a new valve must be with manufacturing defect) which is beirher expected nor suspected with a new one.

Glad you finally got it sorted Fredy - and it turned out an easy fix.
I have installed or repaired a lot of heating systems and came across faulty valves on the return.
Still remember it happened to me on one radiator on a brand new system. Quality valve, but it would only allow water to flow through from the pipe, but not the reverse due to the brass seal being loose

 

[Fredy]

In my previous post it’s concluding sentence was spell checked by by my smart phone resulted “beirher” instaed of “beirher”. Please accept my apology.

APOLOGY! I meant to say NEITHER.

 

[Harvest Fields]

Glad it is sorted for you