Balancing UFH system

[MrSniff]

Hi, struggling to balance our UFH system (three floors each with a manifold, some with more than one zone; no mixing at the manifold as water temperature set at heat exchanger based on outside temperature). So, stupid question which I should know but can’t seem to get my head around: for zones I want to transfer less heat into the floor, do I reduce the flow rate or increase it?

 

I also wonder whether it is more efficient to keep the system consistent 24 hours, or use a set-back overnight?

 

Many thanks for any help!

Edited Sunday at 21:16 by MrSniff

[JohnMo]

Zone why? Is there a specific need. If a single zone can call for heat how is your heat source managing flow do you have a bypass or buffer etc?

 

To balance I simply opened all flow meters fully. This gives heat source freedom to flow what it needs to get the correct dT. Then if a room is too warm, you reduce flow to increase dT across that loop(s). Decreased flow increases dT and therefore mean flow temperature decreases, decreasing floor output. If whole house is too warm decrease heat output from boiler or heat pump. If house is too cool increase output temperature and get house stable, correct warm rooms. Leave 24 hrs min between setting changes.

 

14 minutes ago, MrSniff said:

also wonder whether it is more efficient to keep the system consistent 24 hours, or use a set-back overnight?

The house will use about the same energy setback or not, as the heating has the increase fabric temperature after setback. If using a heat pump, this requires higher flow temperature and loss of CoP.

[MrSniff]

Thanks for the reply, very helpful.

 

The zones equate to different rooms on the same floor / manifold. We are on a district heating system, so no bypass or buffer, just a progressive valve allowing flow from the district heater through the heat exchanger to manage "secondary" water temp to the manifolds based on outside temp.