hyso80

do you mind resending the link? seems to have an error. thanks for the suggestions.

Fair point - I spent some good time last winter trying to balance. Even when closing all rads as a test the last rad didn't warm up. I also found the heat pump cycled more if I closed off the easy loops (UFH nearest the main feed/return) and weren't getting enough heat in the house. Pipe dream at the moment (!), but hoping to put UFH across most of downstairs over time. Will look to add flexi pipes. I have found 500mm full bore 1" which sound like will do the trick then.

Heading into the cold season I’m reminded I still need to sort the upstairs feed and return. Setup: 8kW GSHP → 2 UFH zones one side, 2 big rads in the middle, and no heating in the kitchen (all open loop). Pipework is 28mm from the HP, splitting into: 22mm for UFH (2 rooms), dropping to 16mm with 250mm spacing 22mm for downstairs rads (probably drops to 15mm underground) 15mm for all of upstairs (first metre is 15mm plastic, so more like 12mm). Result: the last rads upstairs don’t really warm up, not helped by the HP’s 15-min cycles. It also means one side of the house (with UFH) gets really warm, while the rest is kind of relying on it. Planning to upgrade most of the upstairs pipework (luckily the routes are straightforward). Debating whether to go 28mm copper with 15mm tees to rads. Heat-engineer calcs say 22mm is fine, but I may add UFH in the bathrooms later and it’d be handy to keep the option of running CH to the kitchen (downstairs is a concrete slab). So… is 28mm overkill, or am I missing something obvious? Side note (maybe for another post): I also need to tackle compressor vibration noise through the pipes. We only moved in last year, and the HP was installed back in 2008, so I appreciate it’s not the quietest. Anyone got experience with this? I’ve seen suggestions of using 900mm flexible pipes in a U, but not sure how practical that is.