Lockshield and TRVs

[Doobrey]

Hi all,

You have been incredibly helpful in the past and therefore I am hoping you can help me again!

I have a radiator problem.

Since moving in, the radiator upstaris in the spare bedroom has never been able to get hot. This was installed by the previous owner.

All other radiators in the house get hot easily, within minutes of the heating being requested.

On the flow side of the radiator, we have the TRV, the pipe work gets hot (very hot).

The Lockshield on the return is open. I've tried restricting, through to fully open. The radiator gets slightly "warm" but not hot.

I've tried slight adjustment on the lockshields on the other radiators, but no avaiil.

I have tried closing the TRV and bleeding the radiator, water flows. I've tried closing the lockshield, leaving TRV open, bleeding and water flows.

The lockshield and the pipe on that side never gets warm, so I am suspecting a faulty lockshield.

Any thoughts? Do you think its the lockshield also? Is there a way to prove/test this?

With thanks

Doobs!

 

[terryplumb]

Close the TRV on every radiator that heats fully, run heating ,and see if problem rad now heats fully ( both it's valves fully open of course)

 

[Doobrey]

Close the TRV on every radiator that heats fully, run heating ,and see if problem rad now heats fully ( both it's valves fully open of course)

Thanks ill give this a try in the morning.

Assuming it does heat up, any thoughts?

 

[terryplumb]

If it heats fully there would obviously be nothing wrong the plumbing to it / valves or radiator. The system would probably just need balancing.

 

[Doobrey]

Morning,

Thank you for the suggestion. I have tried the test. IE. closed all TRVs off, except the radiator that doesn't heat up.

The radiator flow pipe gets "warm" and there is some minor heat in the radiator. When I say heat, slight warmth.

I am suspecting 1 of 2 things. Either the valve/s on the radiator are broken in some way, or, (bearing in mind I didn't install this radiator), that the previous house owner has connected the return incorrectly. If the latter, any idea how I could confirm this?

With thanks

Doobs

 

[terryplumb]

There is no circulation,so could be plumbed wrong, valve fault,or blockage ,often in pipework.
Can you remove the radiator to do some tests ?

 

[Doobrey]

That's kinda what I thought too.

Yup, I will remove the radiator. I am thinking, removing it, check for sludge (maybe an obvious one), then on the lockshield side, open it open to see if any sludge or blockage on that side. If that is clear then I can only assume its plumbed in wrong.

Any other suggestions would be much appreciated!

Thanks TerryPlumb!

 

[terryplumb]

Does the pin in the TRV move freely up and down when pressed ?

 

[alan333]

Not a plumber but learned a lot on my old system diagnosing similar problems.
Close both valves on the faulty rad. Open bleed valve only long enough to let the pressure out. Open one valve and open bleed valve again - if decent water flow comes out it's flowing ok from that valve/end. Do same on other valve and compare.
You can do the same on a bigger scale by closing off both valves, open bleed valve to let pressure out then close it again, and unscrew one valve from the radiator (with a tray underneath to catch the water, surprisingly it won't run that much). Check the flow when you open the valve. Compare with the other one.

 

[Doobrey]

Does the pin in the TRV move freely up and down when pressed ?

Yup sure does

 

[terryplumb]

Is your heating system fed from a small loft tank ( f&e cistern) or pressurised / sealed ?
Take the rad off and run water from each valve to a drain ,let each one run for a couple of minutes. If system is sealed you need to keep pressure topped up whilst doing so.

 

[Doobrey]

Is your heating system fed from a small loft tank ( f&e cistern) or pressurised / sealed ?
Take the rad off and run water from each valve to a drain ,let each one run for a couple of minutes. If system is sealed you need to keep pressure topped up whilst doing so.

System is a combi boiler which is pressurised. I have the ability to refill the system if the pressure is low.

I will take the radiator off, connecting to a hose to the drain, keeping the pressure built up. I can't do this till either Wednesday or next week, Terryplumb, however I will definitely do this during the week.

I assume I am trying to check/remove any air or sludge in the system?

Cheer again for the help/support!

Doobs

 

[terryplumb]

Yes ,primarily to ensure there is no blockage / restriction.

 

[Doobrey]

Ok,

I have lifted the floor, before flushing or doing anything in the system. In the picture attached you can see the radiator in the room (top left, with the TRV on the flow side marked in red). This flow comes from "somewhere" else in the house. However, when the system is on, the pipe gets hot, so I assume that this is correct for flow.

On the left hand side of this radiator is the return (marked in blue), which doesn't get hot obviously and flows back to somewhere else in the house. Please note, all other rads in the house work as expected.

The pipes that go off to the right of the picture, red labelled as flow, blue labelled as return go to a downstairs radiator, which the flow pipe doesn't get hot. Luke warm, if I turn off this radiator and stop all flow to it.

If on the downstairs radiator I close both lockshield and TRV, then "some" warmth can be felt on the radiator in the picture, the flow pipe is hot, however, the return makes no sound and doesn't even get warm. Hence I am thinking some form of blockage.

I suspect the return is blocked or not working at that T-Junction (on both flow and return). Additionally my thoughts are, if there is a T junction close to both radiators, will that potentially conflict with each other? In other words, the flow hitting that from the left and then hitting from the right, so pushing and pulling against each other?

An additional thought, if I block off both of the T junctions (flow and return) and stop waster flowing to the downstairs radiator and see if I get decent flow and return back to this radiator in this room?

Would value your thoughts.

Is the T junction right?!?!?

Thanks,

Doobs

 

[Doobrey]

Additional question

Should the pipework be adjusted as per this diagram

With the yellow being the return (moving the T-Junction away from the radiator) and the same with the green being the flow?

That way, in my mind at least, they are not "fighting" each other for flow or return?