Why are 3 of my radiators not working?

If you have the heating on, and as the other guy stated, the valves may not be multi directional, if you feel below the valve on the pipework, check to see which is the hottest, the hottest one will be the flow from the boiler, make sure the arrow on the TRV is facing in to the rad if fitted on the flow, and vica versa if fitted on the return.
The only other thing is air, make sure you have bled all the rads in succession, when the system is cold.

Gary B
February 2007

Are the trvs old, if so they may not be bidirectional which means the pipes must be connected the correct eay roundie valve on flow.
Try turning of all rads that are working and see what happens

mr gas
February 2007

I WOULD SAY YOU HAVE TRAPPED AIR IN PIPEWORK

HI-SPEC PLUMBING
February 2007