Heating not working

[Callistaraines]

One for @pigletjohn.

we have a large house with 22! Radiators. Upstairs is on one system with control panel and downstairs on another with separate control.
radiators both upstairs and downstairs have only been getting warm not hot.
we have hot water. All three systems don't seem to work when on together

heating engineer came out today and said that boiler is cutting off to stop overheating therefore radiators not getting hot.

we have a magnetic valve which he took off and emptied it was completely full of sludge.

he has recommended a flush of the pipework around the pump and possibly a new pump.

he has then suggested either a chemical flush or a power flush.

Does this sound about right??

If it was red hot during the power flush then it is definitely connected and has clear flow, so there's unlikely to be a major issue with the pipework, especially if it worked before.

As piglet John says, that's the whole point of balancing. At the moment the water finds it easier to go through all the other radiators rather than that one, so that's what it does.

When it's balanced they will set it up so water passed through them all at the right speed, it might require the pump to be turned up if the system is complex, but it should be possible to get them all to warm up evenly

As above if you really can't wait, turn off all other upstairs radiators, make sure that one is on at both ends, then turn on the upstairs heating only.
Nothing else should warm up, but that radiator should. That proves that it can work. Then you can open the rest and wait for them to balance it next week.