UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

gterr

hebridean wrote: »

On reading this thread over a period of time and as the general opinion seems to be that the pump is left on but thermostats are set back at certain times i've bought Danfoss TP5000m proframmable thermostats. These will be for the ground floor rooms but i'm at a loss to know what to about the radiatored upstairs rooms. They have trv's fitted but there are no room thermostats.
Any suggestions would be much appreciated. Many thanks.

Hi there,

If you have the time you might like to look at 'my' thread: "ASHP: lagging pipes in loft" which is a bit buried now (but will be restarted in the New Year!). This started as a thread about pipe lagging but soon moved on to matters including control of a mixed UF and radiator system. In our case we seem to be missing a by-pass valve, which means that flow rate is impeded if we use the radiator TRVs. We are still juggling things, and economy is not wonderful (yet). We were on Economy 10 but came off it because we realised we needed to run the pump 24/7, with only very minor backing-off of the UF thermostats overnight. Your system may be quite different to ours, though.

hebridean

Hi gterr, I've just read through the thread you mentioned which has helped and confused me in equal amounts. I'm going to have to get to grips with the set up of my system before deciding on how i'm going to proceed, though i'm at work at the moment and won't be home for a week.
Many thanks.

nande2000

I tried having the pump on all the time with a programable thermostat and some days it did leave me with cooler hot water. I think the heating needs to be off at least 2hrs a day to be dedicated to heating the hot water tank.

gterr

nande2000 wrote: »

I tried having the pump on all the time with a programable thermostat and some days it did leave me with cooler hot water. I think the heating needs to be off at least 2hrs a day to be dedicated to heating the hot water tank.

Depends on the make and model of pump, I think. Our Worcester-Bosch gives priority to domestic hot water heating, but only for the first 20 minutes of any period when both room heating and hot water heating systems are both demanding heat. So, our pump is on 24/7. The UF room stats are backed off a tiny bit overnight, and the rads are on timers. We have a big 'primary store' of heating water in the loft which helps deal with demand.

nande2000

Anyone had any problems with ASHPs causing "islanding" problems with PV inverters ?
My PV inverter shut down this morning at the same time that my DHW cycle started on my Ecodan. I spoke to the the inverter company and they said it is possible that the compressor turning on caused a spike that the inverter thought was an issue with the grid and so it turned itself off and back on. Is there a way of smoothing the startup of the heatpump ?

[Deleted User]

nande2000 wrote: »

Anyone had any problems with ASHPs causing "islanding" problems with PV inverters ?
My PV inverter shut down this morning at the same time that my DHW cycle started on my Ecodan. I spoke to the the inverter company and they said it is possible that the compressor turning on caused a spike that the inverter thought was an issue with the grid and so it turned itself off and back on. Is there a way of smoothing the startup of the heatpump ?

Is there not a DIP switch on the FCT2 controller that changes the DHW mode. i.e heat water flat out [poor cop] OR heat water gently [better cop] ? Just an idea that might give you the soft start you are looking for... As you have an Immersun it might work out better for you.

Sorry, I have assumed that you have the FCT2 controller and DHW mode set to heat water flat out but might be worth a check

John_Pierpoint

nande2000 wrote: »

Anyone had any problems with ASHPs causing "islanding" problems with PV inverters ?
My PV inverter shut down this morning at the same time that my DHW cycle started on my Ecodan. I spoke to the the inverter company and they said it is possible that the compressor turning on caused a spike that the inverter thought was an issue with the grid and so it turned itself off and back on. Is there a way of smoothing the startup of the heatpump ?

I have an "Aurora" PV inverter and have short term drop outs caused by over voltage in the mains (according to the inverter).

The "Aurora" (Californian design made in Italy) continually scrolls round a display of its parameters checking the performance of my wiring, its panels and the characteristics of the grid.
What does your inverter offer in the way of diagnostic parameters?

I would think the "Ecodan" has soft start with a scroll compressor using inverter technology ? It does not get much better than that ?

I am particularly interested in your experience, as I have an ambition to add a heat pump to my property.

nennyrainbow

I also have an Aurora PV inverter and have had an Ecodan (or Zubadan) fitted 3 weeks ago with no problems or cut outs so far. Sorry, probably not much help in terms of advice.

dullnote

Hi also have Aurora. Pv with Danfoss ASHP never had issue, until this. Morning with compressor fault, reset it and away it went never thought about voltage issue, but also never had a issue with Pv, except sun never out for the last two week

Dullnote

nande2000

I checked the dip switches last night and they are optimised for maximum cop. I watched the dhw cycle start this morning and the error didn't repeat. Maybe there was a small fault in the grid at the same time as the compressor spike ? I'll keep an eye on it from now on to see if its a regular occurrence.