Henco underfloor heating

[sw197]

I wonder if anyone can help. I have henco underfloor heating running from a Worcester bosch gas condensing boiler greenstar 15i. The boiler has three two way zone valves, one for central heating radiators, one for hot water, one for underfloor heating. The water and radiators have there own programmer. The radiators have a dedicated thermostat. The underfloor heating has its own brass manifold, own pump grundfos ups2 ph 50/60, it's own programmer and its own thermostat. When I switch my water or my radiators on the underfloor heating pump switches on even though the underfloor heating controller and thermostat is off. The underfloor heating doesn't switch on its just the pump running. If I switch the underfloor heating on at the controller and thermostat it heats up fine. My question is why is the underfloor heating pump coming on with water and radiators - doesn't the boiler have a pump running these. Why would I want my underfloor heating pump running for what seems a needless reason? Also the thermostat on the manifold for underfloor heating is down at 40 degrees - should this be higher? Any help appreciated.

 

[Pipes Plumbing]

As per the replies to your other thread, it is down to the way it has been wired and possible the controller you are using. We come across this quite frequently and it will take a heating engineer familiar with both the wet and electrical side of things to be able to give you the best advice once they have seen exactly what is in place and how the original installer has put it all together.