Ecodan Heat Pump temperature help - should the pump always be on?

Forum|Forum|2 years ago
November 11, 2023
18 replies
2367 views

Hi Everyone,

Apologies in advance if this has been asked before, I’ve been looking through google and this forum seems to be very helpful.

I’m running a Ecodan heat pump with underfloor heating only ( no radiators)

but I’m finding there is no information online on how to run the system properly and most efficiently, it’s rather frustrating.

There is a lot talk about cop figures ? I have no idea how I obtain these figures from my controller or Mel cloud app

I have 4 thermostats and use a Heatmiser app for a timer ( 4am - 10pm and then a 2 degree drop off from 10pm) .

Two rooms achieve solar gain and are hotter than the other two rooms. I don’t use the other rooms often so I have the thermostats low in those rooms so they never call for heat.

There’s a lot of talk about running the system low and slow 24/7 .

The only way to run 24/7 is to run the thermostats in the rooms higher than my desired temperature so the pump is always on?
Won’t this uses more KW?

If one thermostat is calling for heat, does it use as much energy if all the thermostats were calling for heat?

Sorry for all the questions, I’m hoping you can help me

Best answer by juliamc

You can calculate the COP by dividing the heat energy produced (in kWh) by the amount of electricity used (also in kWh). Hopefully it’ll be 3.5 or more.

There’s no benefit gained by not heating rarely used rooms, because adjacent warmer rooms would just lose heat to them anyway; also the heat pump works best when there’s a good flow of water around the heating coils. So open up all your thermostats rather than strangle the flow.
Depending on what flow temperature you have (hope it’s on weather dependent control), you will get a higher COP if you can lower your flow temperature while still achieving your target room temperature.

Definitely check HeatGeek.com for some more advice !!

Show previous replies

L

LordHarry

Newcomer

The Mitsubishi system is poor at measuring its own consumption at low current draws, I find it is quite variable but averages at 1.5kWh a day, or 500kWh a year – this makes quite a difference to the reported COP values. During the summer when no heating runs my system reports 3kWh a day of ‘heating’ consumption, in reality the system is using 0.5kWh a day to run the FTC board and the MelCloud wifi dongle. It looks worse than it is in reality. The COP for HW will always be lower than the COP for heating as a proportionately larger chunk of its time is spent pushing the flow temps to their highest. This is also a good reason for not running a HW cycle in the coldest part of the day if you can help it (unless its also cheap electric).

The advice about 24/7 refers to not programming on/off periods like most people do with gas CH. Temperature setbacks work a bit like turning a system off as the heat demand will be judged to be satisfied, but having it come back on when the temp drops by 2 degrees, say, allows the system to select the time when to come back on and work not too hard to bring the temp back up.

I think you need to set TRVs properly in rooms that get a lot of solar gain so that they can take themselves out of the heating load, but not just stop the whole heating cycle as other rooms will still need some heat. If you look at the hourly temperature records of the flow and return temps you can see whether you system is supplying heat continually or in short bursts, aka cycling, this will help you aim to set a target flow temperature low enough to keep it going for longer periods.

M

MonkswoodAuthor

Rank 2

The Mitsubishi system is poor at measuring its own consumption at low current draws, I find it is quite variable but averages at 1.5kWh a day, or 500kWh a year – this makes quite a difference to the reported COP values. During the summer when no heating runs my system reports 3kWh a day of ‘heating’ consumption, in reality the system is using 0.5kWh a day to run the FTC board and the MelCloud wifi dongle. It looks worse than it is in reality. The COP for HW will always be lower than the COP for heating as a proportionately larger chunk of its time is spent pushing the flow temps to their highest. This is also a good reason for not running a HW cycle in the coldest part of the day if you can help it (unless its also cheap electric).

The advice about 24/7 refers to not programming on/off periods like most people do with gas CH. Temperature setbacks work a bit like turning a system off as the heat demand will be judged to be satisfied, but having it come back on when the temp drops by 2 degrees, say, allows the system to select the time when to come back on and work not too hard to bring the temp back up.

I think you need to set TRVs properly in rooms that get a lot of solar gain so that they can take themselves out of the heating load, but not just stop the whole heating cycle as other rooms will still need some heat. If you look at the hourly temperature records of the flow and return temps you can see whether you system is supplying heat continually or in short bursts, aka cycling, this will help you aim to set a target flow temperature low enough to keep it going for longer periods.

How do I check my hourly temperature records of the return temps? This seems interesting to see whether it’s cycling (lower cop or heating continually)

Tim_OVO

OVO Forum Legend

How do I check my hourly temperature records of the return temps? This seems interesting to see whether it’s cycling (lower cop or heating continually)

@LordHarry any idea?

Carbon neutral - we need a community to get there! My green tech: Aclara SGM 1411-B smart meter, Chameleon IHD6

L

LordHarry

Newcomer

You have the MelCloud app - it is available in the hourly temperature tab.

M

MonkswoodAuthor

Rank 2