Pta

Got plumber to open up mixer valve and was full of sludge and metal debris. The hot pipe from boiler to mixer was also full of sludge/metal. Remove what we could and now ufh working much better getting a delta of 14 degrees rather than 25

Something i did notice when flushing the system a few days ago was if more than say 4 loops were open then flow rate would show zero even though water was coming out. However when each loop was open 1 at a time all showed full flow. Outside flow rate is above 30 lpm and at around 6 bar. Its almost as though if you have pipe lenghts of 80to 100m there shouldnt be more than 5 loops per manifold as perhaps the pump isnt powerfull enough to produce say 20lpm to give approx 2lpm per ciruit?

Hi, the mixer valve is set at just above 45 degrees and actual flow temp is around 43 degrees so not too much difference. Have a plumber who hopefully will come this week to correct the pump positioning etc.

Thanks alot will try this and hopefully will sort the flow rates out. Just do triple check the metal part below the pump going into the manifold can be adjusted to face the opposite way? And same with the top C and H on top?

No worries, appreciate everyones help on this. I do know of a plumber however would need to tell him what to do. Just to clarify do I just need the pump put the right way up and the the mixer valve will be below the pump rather than on top atm? the flow and return from boiler pipes just need readjusting slightly lower. This would result in top manifold being flow and return being the lower one? The acutator cables are long enough to reach both manifolds.

Pic of flow meter 0 is at the bottom and has writing up to 2.6lpm. Yes pump is upside down to fit from left to right as the flow comes to the lower bar and return to the top. I though a pump could be fitted either way, if not i dont think ive seen anything online for a right side fitting all seem to be left, could you suggest one thanks. This was done 3 years ago so the guy wont come back.

The top manifold is return with a C sign on that same line there is an H sign which is hot from boiler and pipe infront is C for cold returning to boiler In other manifolds ive seen both C's are in line and the H is in front.

Sorry to try and clear up only 1 manifold however I switched the flow and acutator bara around to see if that would make a difference however didnt. I dont think the flow was ever high if more than 1 zone was open. I have bled the system so no air. Even though with all zones open it shows zero flow I can feel the flow pipe get hot however the return is too cold i.e 20 to 25 degrees difference between flow and return temperature even after 2 to 3 hours which would mean somehow flow is restricted. Just and fyi for hot water to kitchen sink I used the ssme 16mm pipe under the screed and within 1 min of it on the tiles it runs under get warm. Just not sure what is restricting the flow. Will post some more detailed pics. Thanks

Hi, can anybody assist me with the issue I am having of low flow rates. Below is an explanation of what has been done/tested. Not sure what else to do. Thanks. Flow meters are on the return side as that is how they work need water pushing them up. Manifold is installed roughly 2m above the floor. All i can think of is there is a design flaw with the thermostastic valve flow and return as the return manifold cool water is on the same side as boiler hot flow coming in? The flow side of pipes heat up and so does the return pipe after several hours however i believe due to the flow rates showing zero the flow is going through slower resulting in a longer warm up time. An example is when mixing valve set at 45 after around 3 hours or so return temp is around 25ish so seems to be flow is too slow( insulation was 100mm celeotex and pipe spacing 150mm apart, 16mm pex pipe, most loop lengths under 100m 2 or above at around 107ish). Also to note is if the pump is set to constant pressure which is what i believe it should be set to the pump works slowly i.e only 2 lights would be on. Whereas on proportional pressure i can get 4 and sometimes all 5 light on meaning pump running on full, however neither setting seems to affect flow rate. One more thing to mention is if a smaller zone was open only then the flow meter showed flow to max when fully open however when more loops or zones are open drops back down to show zero, also oddly if only one zone open and I reduce the mixing valve to say 30 the flow rate on that zone would increase and the pump would run on full however if i increased say to 50 flow rate would drop and pump speed also even though set on highest setting. I also did notice that if only 1 zone was open it would heat up much quicker than if more zones were open together both in flow rate showing and from time taken for return temp to be higher.