Twob radiators radiators not reaching temp

[Ash101]

Evening all!
I could really do with some expert advice regarding two radiators that are not reaching the same heat as the others.
It's a worcester combi system.

OK so the two radiators are located back to back, one in the kitchen and one in the lounge. The feed to the lockshield in the kitchen is cold and the the feed to the prv in the longe is cold (sort of tells me that the prv is on the wrong side on one of them)

I removed and capped off a rad in a upstairs bedroom over the summer so was sort of thinking could it be a airlock issue?

Any advice /suggestions what the issue is would be much appreciated 👍
Regards Ian

 

[Chuck]

If this proble, suddenly appeared after your DIY session then an air lock would be top of my list. I assume you have tried going round bleeding the system? If not, do so. Otherwise, try shutting the TRVs on all the other radiators in the house and open the TRV on the cold radiator. Run the heating and see if you can get some circulation through the cold radiators.

 

[Ash101]

If this proble, suddenly appeared after your DIY session then an air lock would be top of my list. I assume you have tried going round bleeding the system? If not, do so. Otherwise, try shutting the TRVs on all the other radiators in the house and open the TRV on the cold radiator. Run the heating and see if you can get some circulation through the cold radiators.

Thanks for the reply.
I'm unsure when the problem accured as we haven't put the heating on since I removed the radiator.
However after digging a bit deeper on Google im currently doing the turn off rads method you've suggested and the radiators and return pipe have reached a good heat..
Fingers crossed its sorted..
Thanks for your help much appreciated.. I may be back when I turn the rads back on if the problem returns 😁
Stay safe 👍
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If this proble, suddenly appeared after your DIY session then an air lock would be top of my list. I assume you have tried going round bleeding the system? If not, do so. Otherwise, try shutting the TRVs on all the other radiators in the house and open the TRV on the cold radiator. Run the heating and see if you can get some circulation through the cold radiators.

OK so iv opened the rest of the rads and temp has dropped in the two rads in question also the return pipe temp has dropped to tepid again.
Any ideas?
Regards Ian

 

[Chuck]

OK so iv opened the rest of the rads and temp has dropped in the two rads in question also the return pipe temp has dropped to tepid again.

Okay, so you've proved that there is no blockage and no airlock, which is good. What's left is the system needs 'balancing'. This involves fully opening all the TRVs everywhere, going round one radiator at a time and using the lockshield valves to adjust each so it gets its fair share of hot water. The easiest way to do this is to get a pair of pipe thermometers and set each radiator up so that its return temperature is about 10°C lower than its flow temperature.

(If you don't have a thermometer, you can try the following: Run the boiler with a flow temperature of 60°C when the returns are at 50°C you'll be able to hold your thumb on the return pipe and it will take 10s to get painful. Less than 10s => close the lockshield a bit, more than 10s => open it a bit.)

You'll probably need to go round twice if it's not already pretty close to okay.

Searching this site or Googling will find thousands of detailed how-to's.

 

[Last Plumber]

What size are those two radiators and the pipes that feed them?

 

[Ash101]

What size are those two radiators and the pipes that feed them?

What size are those two radiators and the pipes that feed them?

I believe they're 1800mm.

What size are those two radiators and the pipes that feed them?

I believe they're 1800mm, definitely 15mm pipes.
I checked the lockshields this morning they're all set at approx 1/4 of a turn out, Every other radiator is extremely hot but the two in question are just hot, it's a 3 story house boiler and two rads in basement 4 rads ground floor 4 rads top floor the two problem rads are 2nd floor guessing they're 3rd and 4th rad from the boiler 👍

 

[Alan Wright]

To maintain flow to any radiator or group of radiators you can use a radiator flow booster:-

https://showerpowerbooster.co.uk/blog/radiator-flow-booster/

 

[Last Plumber]

I believe they're 1800mm, definitely 15mm pipes.

1800mm x ? and what are they?
e.g. 1800 x 600 K2 (double with 2 sets of fins). The achievable flow rate is governed by the pipe size you have amongst other things. It may well be that they are over sized for the pipework.