Probs with Cent. Heating

[Shivery]

Radiators upstairs hot downstairs cold -if upstairs switched off some of downstairs rads will heat. New pump,3-way valve,gas valve have just been fitted and system professionally flushed out.
(When boiler turned on it fires up pipe and pipe in loft brings water up to 3-way valve system. When boiler reaches a certain temperature it cuts out before all radiators hot.) Any help appreciated

 

[kevplumb]

whats the pump speed on

 

[chrishutt]

New pump,3-way valve, gas valve have just been fitted and system professionally flushed out.

The people who carried out this work should be called back to sort this out (no further charge). If I carried out the work described, I would expect to leave the system properly balanced and working.

 

[MANDATE]

The boiler should cut out when a certain temperture is reached, but is your boiler stat set too low.
With the work carried out I can;t see it being a blockage but is it possible the pipe work splits into upstairs and downstairs and there is air in the downstairs circuit.
I think I would close off all upstairs rads and increase the pump speed and the boiler stat. I would expect this to push the water around the circuit and allow any air to escape up the vent pipe or into radiators where it can be bled off,
Can't think of anything else at the moment.