7° delta t

[john0wingnut]

Found this thread interesting, as I am currently tinkering with my setup and also not hitting delta T of 7 on my UFH.

 

I have Salus auto balance actuators, 2 manifolds - 12 and a 5. 180Sqm slab, 11 zones. I have turned the stats all to max, so they stay on / open and act as one zone to let weather compensation do its thing. Weather compensation curve is asking for 25.9 degs flow temp currently.

 

Just now, flow to UFH heating is 27.7 and return is 25 degs. This morning, when I checked, flow was 26.9 and return was 24.1

 

UFH pump is a Wilo Yonos Para 25/6, set to constant pressure on setting 3 of 6, which is a 3m head. Flow rates vs designed vary across the loops. eg my lounge has 2 loops of 85m with a 1.3l/m flow rate, and this is bang on. Ensuite is 50m single loop and should be 0.9l by with the Salus ABA its sitting at 2l/min.

 

Heatpump is putting out 28.4 with a return of 24.5. Very similar this morning. Looks to work to a dT of 4 or 5, which is modulated via the the charge pump speed.

 

All rooms are maintaining 21 degrees +/- 0.2 degrees, except the lounge which is about 0.5 degs lower.