ASHP UFH manifold flow meter setting help

[MechanicalBuilder]

Hi, 

 

im after some help setting my UFH manifold. The plumber set all my actuators wide open even though I have varying loop lengths (1 is 60m, a couple are 90 and the remaining 100m-ish)

 

is there a rule of thumb for adjusting the flow meters? Had a mate come over and adjust them using a calculation given by the ufh installer but he then readjusted them using pipe clamps to try and get a difference of 5’c.

 

ive a feeling they still aren’t right!

 

[JohnMo]

More info needed

 

Is manifold connected directly to heat pump?

Do you have a buffer?

Do you have mixer and pump on manifold?

Do you have room thermostats?

[MechanicalBuilder]

Hi John, 

 

thanks for the reply

The manifold is connected directly to the HP with no buffer, mixer or pump. I have room thermostats but I’m not using them. I have the LWT controlling the HP and it’s now modulating using the WDC which has it running more efficiently than it  ever has before!

[MechanicalBuilder]

The HP is a daikin edlv08 for reference 

[JohnMo]

Don't get too hung up dT. Use the settings you have now and fine tune. Start with a reference room say the lounge, don't touch these flow rates if you are happy with room temp.

 

Then balance the flow rates to get the other rooms at your preferred temp.  Increase flow rate, to increase room temp, decrease to get lower room temp.  Leave you reference room flow the same all the time. Leave a good 24 hrs between adjustments. 

[MechanicalBuilder]

1 hour ago, JohnMo said:

Don't get too hung up dT. Use the settings you have now and fine tune. Start with a reference room say the lounge, don't touch these flow rates if you are happy with room temp.

 

Then balance the flow rates to get the other rooms at your preferred temp.  Increase flow rate, to increase room temp, decrease to get lower room temp.  Leave you reference room flow the same all the time. Leave a good 24 hrs between adjustments. 

My concern here is if I turn it down any more I’ll have little to no flow on the flow meters, I think the shorter loops are already down to 0.6l/m.

 

are you suggesting minuscule adjustments as in 1/4 or 8th turn. It’s an ivar manifold similar to the pic 

 

[MechanicalBuilder]

I’ve got the WDC down to ask for 28’c but the ASHP won’t modulate lower than 30’c which is fine but it’s overheating the house  

[JohnMo]

1 hour ago, MechanicalBuilder said:

My concern here is if I turn it down any more I’ll have little to no flow on the flow meters, I

Start with a higher flow rate overall, heat pumps like high flow rates. So not really an issue.

 

My long loops are at about 2.5 l/min.

 

On Daikin units you can adjust the dT, this in turn adjusts many other parameters, such as flow rate. May be worth playing with that also. Think you go in to the heating type to adjust.

 

Another thing to use is one where it runs WC but also uses the built-in thermostat to stop overheating. But what's stopping it going below 30, should be able to select down to 25?