Balancing radiators

[a9blue]

I have 7 radiators running off a 30KW combi in an average sized end terrace. The biggest one is 5000 BTUs.The rest are much smaller.
The pipework runs in 22mm from the boiler for about 3M before dropping down to 15mm for the rest of the system.
I have one or two radiators which dont seem to want to balance.
The boiler pressure is on 2 bar, can anyone help?

 

[LIFES A GAS]

Do the rad you have the problem with get hot when all others are turned off? are the the ones which are furthest from the boiler/pump? Have you checked the TRV's if fitted, are they stuck closed? Close the lockshield valves on the rads that work OK and just crack them 1/4 turn open at first, you can open them a bit more if they dont get hot,
Hope this helps, Martin

 

[Iderown]

Had similar problem here. The rads which would not heat reliably are the two which are "last" in the loop. The pipes take "the scenic route" around our house and have two or three "visits" to the roof-space.
Most rads have TRVs fitted - the two in the hallway, where the main thermostat is, do not have TRVs.
Problem was investigated by closing all rads except the two "problem" ones. Air was heard bubbling into them and they then heated. The cooled again when the others were opened.
The speed of the circulating pump was increased and there has been no further problem.

 

[a9blue]

Thanks for advice but there is no choice of settings on boiler pump.

 

[doitmyself]

Read How to Balance a CH System