New house and radiators upstairs

[TimOs]

I have recently moved into a new house.
When I turn the central heating on all of the houses radiators come on and then after about 1 hour the upstairs radiators go cold. I called a plumber in and he changed the pump at a cost of £400 but the problem hasn't been solved. He is now suggested replacing ALL pipe work and has quoted me £4k.
Any thoughts would be appreciated.

 

[dextrous]

The plumber's a very funny man indeed. What a pillock.

Anyway, bit more information about your system would be useful.