Underfloor heating problem

[match14]

I have an underfloor heating system in my house on both the ground floor and the first floor. The ground floor manifold operates fine but I have a problem with the first floor manifold. If the heating is on downstairs but off upstairs then the return gauge on the upstairs manifold goes up to 60 degrees C and the flow gauge reads 40 degrees C, if the upstairs comes on whilst the ground floor is on then the return gauge drops to 40 degrees C and both the flow and return gauges continue to read 40 degrees C even after an hour.

Any ideas?
Thanks.

 

[Agile]

I am not sure there is anything wrong yet.

Is this a new situation?

Both at 40 C indicates a very high flow rate and the pipes up to temperature. Not necessarily wrong.

But we need further details of your system! Does it have a circulating pump on each manifold?

Tony

 

[match14]

It has always been like this, there is a pump on each manifold and a pump at the boiler too.

The system in question is this one.

http://www.ihsenergy.co.uk/format/images/pdf/ihs_install_manuals/Manual_2008_Danfoss_Wiring_.pdf

 

[oilhead]

May sound silly, but check that the pumps are both installed the right way, and that they pump from the same flow pipe. Saw one a couple of months ago where the upstairs circuit drew from the flow pipe, but the downstairs one from the return. It had been like that for 6 years.

 

[match14]

Ok I'll check that out. Would I just disconnect the flow and return from the boiler at the manifold and see which one has water coming out from it?

 

[oilhead]

You need to be able to follow the pipework from the boiler or thermal store. How far apart are the Manifolds. There will be a directional arrow on the pump body.

 

[match14]

Manifolds are 12metres apart.