Underfloor heating not working

[Swampman]

Hi All
Went to see customer with an UFH problem. Pump not working so replaced, but still no heat! Have heat to manifold via open 2 port motorised valve. Heat starts to enter UFH pipes but does not flow through to return manifold. System has 2 auto air vents but cannot get any air out. Have tried attaching hose to return manifold to purge some water and hopefully some air but no joy! System has 2 loops each controlled by its own stat and TRV. Have removed heads from trv's to see if they are stuck etc. Still no flow. I am assuming its an air problem but any advice would be appreciated.
Cheers

 

[Agile]

Stuck blending valve?

 

[picasso]

Is the new pump getting 240v when you turn the stats up ?

 

[DeltaT2]

Hi All
Went to see customer with an UFH problem. Pump not working so replaced, but still no heat! Have heat to manifold via open 2 port motorised valve. Heat starts to enter UFH pipes but does not flow through to return manifold. System has 2 auto air vents but cannot get any air out. Have tried attaching hose to return manifold to purge some water and hopefully some air but no joy! System has 2 loops each controlled by its own stat and TRV. Have removed heads from trv's to see if they are stuck etc. Still no flow. I am assuming its an air problem but any advice would be appreciated.
Cheers

OK so if it's 'your customer' then they're clearly paying you, why I'm not sure? Because you clearly have very little knowledge of UFH systems & I'm sure they'd be delighted to know you're referring to a DIY forum for enlightenment!!!.............

Right, ask yourself; why do the circulation pump fail or did it fail? Did you check the resistance of the windings or the uF of the capacitor?? Did the circulation pump 'dead head'?? All these questions should have been answered before whipping out a hose! Then as said, double check all electrical controls, are they working correctly? Then as said; check all hydraulic controls...........That should fix it.
HTH............

 

[Swampman]

Thanks for the enlightenment. Electrics operate ok. stats call for heat, they open two port and pump starts to operate. So I guess this only leaves the blending valve as the culprit.

 

[simond]

Without getting huffy puffy like my colleague, Sometimes even a tradesman can surely resort to a forum?

The mixer valve could be blocked or stuck, true enough. But this is extremely rare, and the latter would heat up the return very quickly giving a clue as to the problem.

The 'fault' I've seen often on UFH is that someone puts the pump in the wrong way round, either on the boiler or the manifold. Gives precisely the symptoms described.

 

[DeltaT2]

Without getting huffy puffy like my colleague, Sometimes even a tradesman can surely resort to a forum?

The mixer valve could be blocked or stuck, true enough. But this is extremely rare, and the latter would heat up the return very quickly giving a clue as to the problem.

The 'fault' I've seen often on UFH is that someone puts the pump in the wrong way round, either on the boiler or the manifold. Gives precisely the symptoms described.

Thanks Simond, I've never been anyones 'colleague' before. I feel quite special now...............

 

[Swampman]

Many thanks for assistance. Replaced blending valve and we're away. It seems the old valve was a TMV 2 limited to 48 degrees so was not getting warm enough anyway apart from it being full of crap!

 

[DeltaT2]

Glad you got sorted mate, every day is a Skool day for the hard of thinking............