Underfloor heating

27 Nov 2010
Reaction score
West Midlands
United Kingdom
I have a problem with underfloor heating. The upstairs radiators and boiler all seem OK. The pressure in the underfloor manifold is pulsing, I suspect due to the pump function. The pump is a Grundfos alpha 25-60. The temperature under the floor has dropped to 25 degrees C and the house is cooling slowly.
Any ideas of what the problem is?
Thank you
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Bit more info wouldn't go amiss. Crystal balls are notoriously unreliable in winter.
What happened
When did it start
number of rads
anything to do with the subject really
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It started 2 days ago. The house temp dropped. When I checked for flow at the manifold for the undergloor heating I noticed a pump that is pulsing or sounding like the flow in in waves rather than constant. The flow valves are bouncing up and down with it. The pump is a grundfos alpha 25-60. The system is polyplumb. The boiler and upstairs rads are all working fine. Problem is just the underfloor part.
Hope that helps
Check the filter on the inlet to the tmv.
You're installer should have fitted full bore isolating valves for servicing the mixing assembly so it should be easy to check this.

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