Daikin HP, frost cycling stopping hot water heat up

Has anyone else had a issue with hot water heating up because of frost cycles ? i have had to resort to turning off the HP hot water schedules when when its below 2 degrees C because the hot water does not come back on after the first hot water cycle (stopped by defrost) the hp stays on central heating, when its warmer outside the heat pump manages to heat hot water with no issue ,
now im using the emersion heater to heat the hot water unfortunately it that high up in the tank i dont have enough hot water for the family rush on showers before school and work

does anyone have any ideas how this can be resolved

the hot water schedule should be on until 4:30 am if the hot water is not hot enough

Mine just resumed heating the hot water where it left off

I guess you could have two separate dhw cycles in that period, rather than one big one

i think mine used to do this, maybe i have changed a setting somewhere without realising it,
are you using quiet mode ?
maybe there is a setting somewhere that makes heating a priority will check through later

Not using quiet mode and currently running as Octopus engineer left things (to prove a point), so nowt fancy set.

The defrosts turned last night into a bit of a dogs dinner for steady state running though.

I might have had something similar today.

Showers have been noticeably cold today and the hot water cycle was interrupted by a defrost and failed to resume.

1 Like

yep that looks the same Mark

yep the defrost cycle comes from the central heating so the 3 port valve moves back to central heting , the issue with the daikin system the hot water is only triggered by the start of the heating schedule, its the same with central heating so the only way round this is to use the reheat mode

It’s as if it forgot what it was doing before the defrost.

But to it’s credit what followed was a lovely long steady state operation.

Before reaching a balmy 6C outside and then returning to cycling.

Note the big target steps are the Octopus suggested Madoka modulation of 10 while using the default Octopus curve, which is an excellent way to highlight heat loss might not be what was calculated.

Or schedule back-to-back heating modes? Eg comfort at 2am, 2:30am, 3am, and then off at 4am ?

I just decided to use the api to trigger a boost prior to the heating cycle on the really cold nights, so that the HP could concentrate on room-heating. Only COP of 1, but perhaps it will save elsewhere by not interrupting heating stability.

1 Like

Last night produced the worst defrosting I have seen on my 11kW. Note that it had no issues resuming the hot water cycle and happily got up to temp.

must of been some high humidity periods ,

woke up to freezing fog… with the temperature and dew point converging

1 Like