UFH issue.

[Roy Cowling]

Hi all, just wanted your opinion on the issues I'm having with my underfloor heating.
Our kitchen/diner floor is heated by wet underfloor heating system (polypipe) 3 zones with 2 wired thermostats, probably about 7 years old, we renewed the oil boiler a bout 3.5 years ago. We have lived in our house for 4 years + & heating up the floor has never been equal, some zones heat & the other doesn't . What we discovered late last year was the flow & return were plumbed the wrong way round to blender/mixer valve, we had that rectified by a plumber, but floor still not performing. I have recently changed the following,
1 x pump,
3 x manifold flow meters,
3 x manifold balancing valves,
When the floor comes on (actuators not connected), the pump gets really hot, the floats in the manifold flow meters hardly move when you adjust them, if you close down two zones leaving one zone open,then the float moves slightly when you adjust it, lack of flow ?. The zones still don't feel that warm when all the zones are open, we have better heat having one zone open.
I have an idea what I do next
, just needed other opinions.
Thanks in advance.

 

[Elsa TLC]

I installed a wet system once that the customer didn't get the benefit from as he went over the top with the floor that he was trying to heat.

 

[Exedon]

Far too many variables to give any useful advice.
Here's a few questions
Is system itself clean and has underfloor ever been flushed?
What's the floor covering?
What thickness is screed and what type?
Depth of insulation beneath pipework?
Are you operating system correctly ie do you have a back set temperature no lower than 4C below desired temperature?
Instead of throwing parts at it maybe get someone qualified in this type of system to have a look?
Polypipe do have a list of registered installer's.