Central heating system drained then refilled - 2 radiators not heating

[Bateman1982]

Hello all,
I had the central heating system drained today for a pipe repair, which was completed successfully.
The system has been refilled and all radiators are working except for 2 on the ground floor, which feel ice cold to the touch. The pipes going into the radiator valves also feel really cold.

The rest of them are working great, there's one in the kitchen and one in the lougne on the ground floor which work fine.
I'm in a 3 storey property and the ones on the top floor are piping hot, as are the ones on the middle floor.

What would be your first steps to try and resolve this?
I've run the heating for an hour, turned it off to let it cool and have bled all the radiators in the house but it hasn't made any difference.

I've attached a crudely drawn sketch of my ground floor layout, with red lines showing the hot, functional radiators and yellow lines showing the ones which don't work at all.
The red circle with a B under it is the boiler location.

Must be an airlock or blockage in the pipes leading to those 2 radiators surely?

Any advice welcome, thanks.

 

[HERTS P&D]

Turn on the heating, then turn off the hot radiators and see if the cold ones get hot.

If so then the systen needs to be balanced.

Andy

 

[Bateman1982]

Turn on the heating, then turn off the hot radiators and see if the cold ones get hot.

If so then the systen needs to be balanced.

Andy

Thanks Andy, this was exactly the issue. They heated up straight away when all others were turned off. I've done some brief rebalancing this evening and have now got heat coming out of all radiators!
Thank you very much.