No heating since boiler move but hot water fine

[oldbuffer]

1. When you say all valves are open, are you sure the plastic handles haven't turned leaving the actual valve unmoved? Perhaps take the handles off and check the valves?
2. I wasn't suggesting draining each radiator, but rather flushing through each one individually with all the others shut off.
3. What drain off point did you use to flush the system with the mains connected via the filling loop?
4. You stated that the hot water side was working OK. For that to work the pump will be circulating the hot water round the secondary heat exchanger, so if it does that, then unless it is unable to pump against the heating circuit load, I'd suggest the pump is OK.
5. Overall, I'd expect whoever moved your boiler to take responsibility for restoring the system to full operation. Whether that is at his / her expense, or yours, or somewhere in between would be for negotiation, and would probably depend on what the problem eventually proves to be.

 

[ianmcd]

sounds like your pump is seized

 

[Londoner2]

Is there a screw on the pump you can turn to let out trapped air? The pump is hot as its over heating and shutting boiler down.

 

[Gasguru]

It's a combi...if the DHW appears to be ok then the pump is working to some extent and would certainly be capable of heating several rads.