NU Heat system Water Underfloor Heating

Postby m66rus » Sat Dec 16, 2017 9:09 am

So over a week ago, my underfloor heating stopped heating the 4 rooms downstairs. Upstairs has radiators and works fine.

So the system is a NU Heat system, I checked various things and thought I had found the problem when I took off the pump screw and moved the inner wheel with a screwdriver the hall was warm in the morning. So, I turned on each of the other rooms and left it for the day. When I returned from work the hall was warmish but the other rooms were still cold.
So last night I replaced the pump to be on the safe side and was hoping that would solve the problem. The hall was again warmish but the rest of the rooms were still cold. I know they take time to warm up but have in the past been fairly quick.

Now heat to the supply manifold is hot and the return is cold. The supply feeder pipes to each of the 4 zones heat up when the thermostat is turned on. I then leave it for a while to see if the zone heats up I monitor the return pipe from the floor to the manifold but it does not change in temporary. The Hall is the only one that has got slightly warmer but only just.

I have changed the temperature on the manifold thermostat as well as the pump speed to see if this makes any difference, but it does not. Perhaps I need to leave it for a couple of days to warm up but as I have said it does not usually take this long.

So should i expect the return pipe or the return manifold to at least change temperature over time. Or if anyone has any suggestions please feel free to comment.


Merry Christmas!!!
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