Hi @weslev, see below
Firstly is it actually necessary, then...
< Up to you, cost vs comfort. At 15m you’re just on the tipping point tbh.
I would be installing in hep2o and am fairly sure that the HRC is ok to be done in the same barrier pipe, is this correct?
< Yup.
Flow and return both in 10mm hep2o or should the flow be larger? does it matter?
< I’d do the lot in 10mm if the hot return is on and left running vs pulsed via a PIR etc. If pulsed, then flow in 15mm and return in 15mm too otherwise it takes a while to get ‘there and back’.
My design for this set up would be to feed the whb's and sink from the main hot manifold but reduce to 10mm, have the HRC come back via 10mm to a return manifold specifically for these three returns, then from manifold run to an isolation valve, followed by a non return valve, then my secondary pump, a final isolation valve and then into UVC somewhere in the upper portion of it if at all possible. Is this logical.
< The HRCs need to come back to individual manifold ports, each with their own isolation valves, same as the hot out manifold; so each pair of hot and hot return can be isolated. This avoids having 3x isolations and a lot of exposed pipework at the basins.
To save faffing on any technical controls, run the HRC from a programmable pump.
< Doesn’t need to be technical. It’s on or off / timed, or triggered by a motion sensor in that room. Typically I work on houses where we’ve installed a decent chunk of solar PV, so I just set these to run all day (if clients are retired / working from home) or on sensors / timed for all other situations. For the retired / other folks the system reverts to the sensors at night, and runs constant through the day, as losses are largely offset by PV anyways. So if you get up to go for a pee, by the time you’ve done the deed and want to wash your hands, the hot water is sat at the tap waiting for you.
Resurrecting old threads is fine, good to blow the dust off them tbh.