Struggling to balance radiators

[gerbils]

Still struggling with this. Am I right in thinking if I close both valves on the radiator - turn heating on - ope both valves - the one that heats up first is the flow? Because on most of them this is the valve with the small cap and not the turn valve which I initially thought controlled the flow and was set to 100% open.

In this case if it doesn't matter should I simply turn both of them 1/4 turn and adjust whichever one I like to get the 12 degrees?

Also, as the rads take so long to heat up it's proving very difficult to pinpoint the first radiator, they all seem to heat up roughly the same time.

 

[Agile]

It is always possible the pump has been replaced but fitted with the flow in the opposite direction.

Normally the pump is on the output of the boiler pumping away from the boiler.

Only on systems before about 1970 it was normal for the pump to be fitted on the return as the water was cooler and that was expected to give a longer pump life.

 

[JohnD]

Still struggling with this. Am I right in thinking if I close both valves on the radiator - turn heating on - ope both valves - the one that heats up first is the flow?

Yes

The valve that you use for balancing must be the one that, when finished, you are going to put the lockshield cap on. It can be whichever you want because, in your case, they are the same. You should not expect to touch it again for years.

Put the manual knob where it is convenient to reach.

 

[JohnD]

Also, as the rads take so long to heat up it's proving very difficult to pinpoint the first radiator, they all seem to heat up roughly the same time.

It doesn't matter which is first.

When balanced, you would hope they all heat up at about the same time

Though the one nearest the room stat must not be quickest.

Any rooms that get too warm, throttle them down a bit by closing the valve a fraction. You can slow down the hot ones, you can't speed up the slow ones by opening them more (though they will get a bit quicker when you slow down all the hot ones)

It can take half an hour for the temperatures to settle down.

 

[gerbils]

It is always possible the pump has been replaced but fitted with the flow in the opposite direction.

Normally the pump is on the output of the boiler pumping away from the boiler.

Only on systems before about 1970 it was normal for the pump to be fitted on the return as the water was cooler and that was expected to give a longer pump life.

I don't even think about that - it was a conversion from a open vented system (1989) to a combi.

 

[gerbils]

It doesn't matter which is first.

When balanced, you would hope they all heat up at about the same time

Though the one nearest the room stat must not be quickest.

Any rooms that get too warm, throttle them down a bit by closing the valve a fraction. You can slow down the hot ones, you can't speed up the slow ones by opening them more (though they will get a bit quicker when you slow down all the hot ones)

It can take half an hour for the temperatures to settle down.

Thank you - so should I fully open one valve like has been suggested previously or should I open them both a 1/4 and then adjust just one of the valves to get the 12 degree balance?

 

[JohnD]

You can open the manual valve fully, and the lockshield a small amount. Enough for the flow pipe to get hot. The radiator will then start warming up, from the top down. It is correct for the top of the rad to be hotter than the bottom. The return pipe will be the coolest part. It will take some time for the radiator temp to stabilise. Do not open or close the lockshield by more than a quarter turn in 30 minutes.

Are you measuring with thermometers of by hand?

 

[gerbils]

You can open the manual valve fully, and the lockshield a small amount. Enough for the flow pipe to get hot. The radiator will then start warming up, from the top down. It is correct for the top of the rad to be hotter than the bottom. The return pipe will be the coolest part. It will take some time for the radiator temp to stabilise. Do not open or close the lockshield by more than a quarter turn in 30 minutes.

Are you measuring with thermometers of by hand?

I have a couple of digital thermometers. I think the poster above is correct and the flow has been switched around, probably why they are unbalanced as the lock shield / return will have been fully open and the flow only 1/4 - 1/2 open.

 

[ericmark]

I have found with the lock shield on the return and the TRV on the supply it was easier to set the lock shield valve, however it still worked when reversed it was just it took a little longer to settle.

I tried to start with closing the lock shield fully, starting with radiator closest to boiler, and opening bit at a time, until I felt hot water in one pipe, then stopped, then looked at the TRV report and if the current exceeded the target closed the lock shield a tad, and giving some time to heat room, also the reverse. It does depend on the make of the TRV head this one does give a better idea of what is going on, the hysteresis is because with this house I have an oil fired boiler which does not modulate.

The eQ-3 TRV head only gives the target, however only cost me £15 each, but since they all have a 32 mm thread I just swap it while I set up lock shields and swap back after.

 

[gerbils]

It is always possible the pump has been replaced but fitted with the flow in the opposite direction.

Normally the pump is on the output of the boiler pumping away from the boiler.

Only on systems before about 1970 it was normal for the pump to be fitted on the return as the water was cooler and that was expected to give a longer pump life.

Just wanted to update this thread for anyone seeing it in the future - the suggestion by @Agile was correct - the installers must have switched the direction of flow. After having so many issues with my rads losing balance, going cold and taking 1-2 hours to heat up, I opened the flow side fully and balanced the return side and it's made a world of difference.

Quieter, heats up in 15 mins and has remained balanced.