UFH trouble shooting

[DIYNovice]

Hello my hearing pump failed over the weekend and a new Grundfos Ups3 was installed to replace Geundfos UPS 15-50. Hot water and central heating were reinstated however as soon as the UFH was turned on the downstairs radiators went cold but the UFH became warm. I have turned everything off and turned on each element one by one but as soon as the UFH is turned on, only the hot water cylinder and upstairs radiator work/receive hot water. Everything worked fine before the pump failed. Any suggestions please.

 

[ShaunCorbs]

Try turning just the ufh heating on for a day constantly

Then re do the test the next day

 

[DIYNovice]

Try turning just the ufh heating on for a day constantly

Then re do the test the next day

Thank you I will try that and report back