Help with wet UFCH please ?

[Upamountain]

Thanks snb 1 - that bedroom was indeed up to temperature so yes, it should be off.
I have checked the small black indicator on the side of both manifold pumps and they are both set to max - 3.
I think that the flow and return pipes to the second further manifold are teed off just downstream of the “mixer” valve and before the first manifold pump.
Thanks Johntheo5 too -so the mixing valve seems to affect the both manifolds. Trouble is the other manifold is at the other end of the house So that pipe run is probably about 30 m. Hence by the time the water gets there it’s down to about 27 degrees. The pipe temperature coming out of the ASHP tank seems to be about 45 degree.
this is our ASHP…hope that’s helpful.

 

[Johntheo5]

Can you determine if mixing is actually taking place and is it required?.

 

[snb1]

When you say heat coming out of airsource tank at 45 degrees do you mean the air source unit, the hot water cylinder or does it have a buffer tank?


the default output from the HP is 45 degrees. As your underfloor was previously Oil then you can set the mixer valve over to manual and adjust it to max.

 

[snb1]

heat pump is 12kw model. Just need the size of the property etc to see what kind of heat loss.

 

[Upamountain]

When you say heat coming out of airsource tank at 45 degrees do you mean the air source unit, the hot water cylinder or does it have a buffer tank?

The lagged central pipe exiting the top of the cylinder. It has a stop cock on it marked ”hot water” where the copper pipe transitions to white plastic - it then disappears into the screed floor . There is a buffer tank in the attic above.

 

[Upamountain]

the default output from the HP is 45 degrees. As your underfloor was previously Oil then you can set the mixer valve over to manual and adjust it to max.

Is the max setting fully anti-clockwise so that the fat end of the edge marking is under the top arrow ?

 

[OvertonPlumber]

The underfloor pumps are 50% smaller than they should be.

They should be 25/60s or 7/8. At that time would have been grey grundfos pumps.
The pump of choice price wise is wilo para atm.

The flow rates on circuits probably a bit high aim for 1-1.5ltr sec on 100mtr circuits. Too high heat won't be dissapated into the screed.

Mixing valves are probably baked they will have spent there life with 70/80c flow down mixing to 45c you suddenly give it ahsp temp it won't like it.

New pumps and new mixing valves, jobs a goodun.

 

[snb1]

those mixing valves won't be affected by the original temps as it is purely a brass valve with a cam that restricts the hot flow to adjust the mixed temp. They are very slow to respond.
flow rate for 100m 16mlcp circuits should be 2.5lt/min.
The flow and return differential should be around 7 degrees ( measured only after circuit has been running for at least 4 hours uninterupted)
25/60-70 are normally used on manifolds upto 12 zones. as these are both smaller then 15/50 pumps should be more than able to do the job, however looking at the age of the pumps it quite likely that they are both under performing and new replacement pumps would be a good idea ( at least that would rule out poor flow)

yes turn anticlockwise to set in manual mode

CP60 pumps from BES.co.uk are 25/60 pumps @60+vat code 21137. Have been using these for about 8 or 9 years without any issues