We have a 14kW Ecodan in our newly built, low-energy all-electric house using the ASHP for all hot water (less boiling tap) and heating - underfloor downstairs only.
I am seeking to get advice on optimum settings for the ASHP to keep our hot water at a 'shower anytime' temp except 10pm-6am.
Tank temp is set at 50degC with 6degC drop. Schedule is On except 4pm-7pm where our Octopus rates go up on the Flux tariff and we switch to export electricity from our solar and battery.
Attached is our tank temp for last 24hrs. I wonder why the water cools so quickly in the tank.
Also I want to know what electric the ASHP is using but can't seem to view thee data on that.
Does your system pump hot water around constantly so you get quick hot water from the tap (secondary return) as this could eat up the hot water.
Or is there a very long leg from the tank to a commonly used tap? Ours takes a good 30 seconds to run hot and the mrs is always turning on “hot” for 20 seconds to wash hands. It never goes hot but the pipes have just been filled with hot water which is then wasted.
250sqm house. 30kWh Sunsynk/Pylontech battery system. 14kWp solar. Ecodan 14kW. BMW iX.
We have a 14kW Ecodan in our newly built, low-energy all-electric house using the ASHP for all hot water (less boiling tap) and heating - underfloor downstairs only.
I am seeking to get advice on optimum settings for the ASHP to keep our hot water at a 'shower anytime' temp except 10pm-6am.
Tank temp is set at 50degC with 6degC drop. Schedule is On except 4pm-7pm where our Octopus rates go up on the Flux tariff and we switch to export electricity from our solar and battery.
Attached is our tank temp for last 24hrs. I wonder why the water cools so quickly in the tank.
Also I want to know what electric the ASHP is using but can't seem to view thee data on that.
Advice on this welcome please?
Thanks. John
It looks like someone had a bath about 6pm and didn't turn the tap off properly. After the 'bath' the tank heats up immediately, then slowly cools down, heats up again and immediately starts cooling - in the middle of the night. The temp drop is too much for normal heat loss and it doesn't happen during the day. Or your hot water is draining away some other way...
@benseb Yes we do have a secondary return in the house because the tank is a long way from our two main bedrooms. I think I'll turn it off to see the effect on water temp, or maybe put it on a timer plug just for the main times that we need the hot water to come through. Thanks.
I think, someone in the past also had a 3 port valve stuck partially open which can mean that while the heating is on the circulating water, at a lower temperature for room heating, was inadvertently cooling the cyl hot water.
But the circulator would have to be activated for that to happen.
@sunandair Thanks for this but the heating hasn't been on.
Thats good to hear. One possibility removed.
It sounds like the Secondary Return, re-circulation, as described above is a reasonable contender… your heat loss is significant since it looks about 11 degrees loss in 6 hours. Whereas an indoor insulated tank of around 250 litres with conventional pipework and modest to short runs of pipework seems to lose around 3.5C in 6 hours (5 degrees in 9 hours, recorded in 5th Feb 2023, set at 48 to 38 reheat)
So with the secondary return pump turned off the new temp chart just shows a bath. I'm going to put the secondary return pump on a timer plug. Thank you 😊
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