Radiator balancing order
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A basic rule for any electrical (or plumbing) problem is..
Assume EVERYTHING you thought you knew was correct is actually WRONG.. unit you have PROVED otherwise.
I am NOT a plumber.. But I have modified my heating system to give 4zones.. (Upstairs, Downstairs, Water & Towel radiators (4 of).
Had a skim read of your post...
My gut feeling would be to do the following:-
(1) Close every radiator value to OFF except 1x valve to 1x radiator..
Repeat for every combination of single radiator to confirm that hot water will flow to every radiator!!!!#
(2) Once it has been confirmed that water will flow to every radiator poistion... then you can start looking at balancing
Assume EVERYTHING you thought you knew was correct is actually WRONG.. unit you have PROVED otherwise.
I am NOT a plumber.. But I have modified my heating system to give 4zones.. (Upstairs, Downstairs, Water & Towel radiators (4 of).
Had a skim read of your post...
My gut feeling would be to do the following:-
(1) Close every radiator value to OFF except 1x valve to 1x radiator..
Repeat for every combination of single radiator to confirm that hot water will flow to every radiator!!!!#
(2) Once it has been confirmed that water will flow to every radiator poistion... then you can start looking at balancing
Sharpend
"It Just Is"
I was taught to work away from the boiler and open each valve slightly more than the previous one until you reach the radiators furthest from the boiler which would then be fully open. This allows the heat to be spread evenly throughout the system.
It has worked for me over the years.
It has worked for me over the years.
Sharpend is spot on, but may I suggest a few basic checks first, (some covered by SL)
1. Make sure you have eliminated all air from (especially) the upstairs radiators.
2. Check system is pressurised about 1 bar. Any zone valves should be set open.
3. Detach the heads from your TRVs and check that the plunger moves.- they can seize up. If stuck, a bit of WD40 and hand pressure down can free them. NEVER pull one up unless you want a fountain!
4. If you've put the TRVs back, have them all set high whilst balancing. - there is no point in trying to adjust the tail valve if the TRV has shut!
5. To give you a better idea of the order to set them switch the system on from cold and briskly walk around feeling pipes and radiators to establish what warms up first.
1. Make sure you have eliminated all air from (especially) the upstairs radiators.
2. Check system is pressurised about 1 bar. Any zone valves should be set open.
3. Detach the heads from your TRVs and check that the plunger moves.- they can seize up. If stuck, a bit of WD40 and hand pressure down can free them. NEVER pull one up unless you want a fountain!
4. If you've put the TRVs back, have them all set high whilst balancing. - there is no point in trying to adjust the tail valve if the TRV has shut!
5. To give you a better idea of the order to set them switch the system on from cold and briskly walk around feeling pipes and radiators to establish what warms up first.
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This article may help you?
https://www.ovoenergy.com/guides/energy-guides/how-to-balance-radiators
https://www.ovoenergy.com/guides/energy-guides/how-to-balance-radiators
I generally work to a 15 - 20°C temperature drop across each radiator for balancing
While balancing radiators may help I find using a thermal image camera can show how efficiently the radiator is actually working and if there is any build up of sludge or magnetite in the radiator stopping or reducing the water flow in the system. If you have a magnetic filter fitted it can be worthwhile cleaning them every 6 - 12 months especially on older systems if you don't have a filter then removing the radiators and flushing them is one option or a powerflush of the whole system would be the best option in clearing out any debris
While balancing radiators may help I find using a thermal image camera can show how efficiently the radiator is actually working and if there is any build up of sludge or magnetite in the radiator stopping or reducing the water flow in the system. If you have a magnetic filter fitted it can be worthwhile cleaning them every 6 - 12 months especially on older systems if you don't have a filter then removing the radiators and flushing them is one option or a powerflush of the whole system would be the best option in clearing out any debris
took me years of fiddling to eventually balance out my rads the way I needed them to work. Biggest issue was my bathroom rad which is right next to the boiler. If I turned that one on full, basically is nothing else got hot. @Sharpend 's advice sounds good to me, wish I had known that one at the time 
I was told: Open the wheel valve/thrmostatic valve fully, screwdown the lockshield and re-open it until, with your ear against the radiator, until you can just hear the water running through it. Stick a couple of magnetic thermometers on the radiator, few quid from Amazon, one on the inlet the other on the outlet. Gradually open the lockshield valve until you get an 11 deg C temperature difference across the radiator.
Start nearest the boiler/pump and work away from that point.
If your radiators have been sized correctly you should find that the radiator temperature will be adequate for the room. If you find the room is overheated keep closing the lockshield until you're satisfied with the temperature.
It's a lot of messing about, probably why it doesn't get done very often. You'll need to go around quite a few times over a period before it settles.
Although it sacrilege to say so, I've never advocted thermostatic rad' valves (personal opinon, you understand, probably in a majority of 1) unless you have a room with a high external thermal gain as they often get stuck closed during the summer and freeing them up only makes a job for the start of the heating season.
Start nearest the boiler/pump and work away from that point.
If your radiators have been sized correctly you should find that the radiator temperature will be adequate for the room. If you find the room is overheated keep closing the lockshield until you're satisfied with the temperature.
It's a lot of messing about, probably why it doesn't get done very often. You'll need to go around quite a few times over a period before it settles.
Although it sacrilege to say so, I've never advocted thermostatic rad' valves (personal opinon, you understand, probably in a majority of 1) unless you have a room with a high external thermal gain as they often get stuck closed during the summer and freeing them up only makes a job for the start of the heating season.
I agree TRVs can be a PIA, especially cheap ones but they do (IMO) result in a more efficient system allowing relatively quick adjustment of individual rooms to varying needs and weather conditions.
They also make system balancing much less critical because once the building is up to temperature the TRVs are in control.
They also make system balancing much less critical because once the building is up to temperature the TRVs are in control.
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Half the battle with radiator balancing is knowing how the pipe routes run around the property..
But when people have home alterations or move house, what limited knowledge there was, can be completely lost.
Also remembering previous builders / plumbers etc may have had added some bits with different pipe diameters,
(e.g. a couple of rads joined via some micro-bore pipe, all other rads 15mm etc..)
And It's not uncommon for a boiler to be moved during a kitchen/utility alteration..
(We've had our boiler moved.. and I've worked on loads of jobs amending wiring for new boiler positions to supply heating controls etc..)
So.. some radiators that used to be on the shortest pipe runs next to the old boiler position can end up somewhere in the middle of a system!!
Bottom line is you cannot assume the physically nearest radiator is actually shortest pipe run.
But when people have home alterations or move house, what limited knowledge there was, can be completely lost.
Also remembering previous builders / plumbers etc may have had added some bits with different pipe diameters,
(e.g. a couple of rads joined via some micro-bore pipe, all other rads 15mm etc..)
And It's not uncommon for a boiler to be moved during a kitchen/utility alteration..
(We've had our boiler moved.. and I've worked on loads of jobs amending wiring for new boiler positions to supply heating controls etc..)
So.. some radiators that used to be on the shortest pipe runs next to the old boiler position can end up somewhere in the middle of a system!!
Bottom line is you cannot assume the physically nearest radiator is actually shortest pipe run.
