Dave C

Very odd - you wonder if you've just got somebody particularly clueless in tech support, because if somebody else with the same model isn't suffering the same power draw issue, it rather suggests there is some setting for controlling it... FWIW, I have the puz-wm50vaa and it's not doing anything of the sort - power draw when the pump is off is negligable (whole house is drawing ~60W during the nighttime when everything is idle, and that includes internet router etc. - and is roughly comparable to what I saw before the heat pump was installed, so I'm reasonably sure the heat pump is drawing <10W when it's idle).

Snap! (well, I have the 5kW Ecodan - but otherwise I'm doing exactly the same dance around trying to do as much on Octopus Go as possible). 30 minutes does seem slow - I haven't timed the switchover on mine exactly but it feels more like 5-10 minutes, which is a lot more reasonable. Couple of ideas: 1) How sure are you the DHW is fully up to temperature? Might seem like a silly question, but ... when my Ecodan was put in, the installer hadn't set the pump speed(s) high enough - so the heat pump ran for ~30 minutes then cut out to prevent overheating. In my case, the DHW wasn't done after 30 minutes, but you do have a more powerful heat pump! If that's happening to you, 30 minutes might be enough to get the DHW nearly done, then it cuts out for a while? (Solution was just turn the pumps up!) 2) What's the max temperature you're aiming for on DHW? Is it possible the flow temperature when it's finishing off the hot water is too high for the UFH so it waits until things have cooled down? 3) Have you timed how long it takes to switch from UFH to DHW? If that's quicker, then bit of a hacky work around, but ... you could set the UFH to run from 00:30, and set the DHW to come on (overriding UFH) at 03:50 or so - that way you get 3h20m of UFH on cheap rate, then your 30m of DHW on cheap rate, and if the heat pump sits around in a mood from 04:30-05:00, well, who cares! Yeah - the Ecodan/FTC manual has a promising setup option for "simultaneous DHW+heating" but when you investigate the details, all that does is allow running the heat pump for heating and firing up the immersion for DHW at the same time ... they really don't want to run DHW+UFH simultaneously.

Hi, In the process of upgrading the heating and insulation on my house - heat pump now in and insulation partially dealt with, have already found the information on the forum about heat pumps useful (I swear there's more useful info on this forum than my installer ever gave me...)