underfloor heating

[Viper Gas]

Hello chaps....been called out to investigate underfloor heating which works intermittently. The boiler works fine.the controls work fine but there seems to be a small loss of pressure. I want to check the pump size and manifold and tubes just not sure how to do that without breaking things out?
Is it worth shutting down all other rads to observe performance of under heating????
Any suggestions much appreciated as usual.

Thanks dd368

 

[smhstu]

Do a pressure test on the pipework to check for leaks
check that the pump is not getting stuck