Ground Source Heat Pumps

encap

Hi Lovesgshp,

I have an emergency right now, the outdoor sensor - looks like is gone, I mean this morning the pump was working as usual, even the warm sunny weather we had for past few days influenced the low energy usage, the daily electricity dropped to 45 kWh overal for the house. But now we have a problem with the sensor, this morning alarm went on and the message says : Alarm (GT2) outdoor sensor. Possible cause: *open circuit wire; *shortcircuit in sensor wire; * connection missing; *sensor malfunction; *temporarily error

What should we do with this? As the alarm is still there and when I check the readings GT2 is empty, also the pump is going on now and the reading for the tgt temp is high about 43, probably because the heat curve is now badly affected without working outdoor sensor? How can I solve that problem or at least find out the cause of this? Thanks in advance

lovesgshp

Hi encap.
Firstly, you need to check the connection on the outside sensor. Turn off the pump, unscrew the outside sensor cover to see if the connections are still ok and not corroded through.
Have checked with our engineers and it is not a problem that has ever been reported, so they have only been able to make a couple of suggestions.
Try this first. Increase the room temp influence to 10, as this overrides the outside stat, and see if there is any change in the operating range on GT1.
The other option, they suggest is to move your internal stat to replace GT1.
You need a electrician with a ohmmeter to check the wiring, or to replace the resistor, otherwise to get in touch with the supplier of the unit to send a replacement. Your landlord hopefully can arrange this.

From our engineer:

"I can suggest, to handle the emergency you can call an electrician for:
1-take GT5 and put it outside instead of GT2 (if the problem is GT2 and NOT the cable). In this way maybe you have to correct the heating curve...
2-connect a 15Kiloohm electrical resistor instead of GT2 in the electrical connections of the heat pump (15000ohm = ca 0°C) and then control heating by using the GT5 setting, increasing it to 10 as the influence."

HTH

encap

Thanks Lovesgshp, I contacted my landlord about this and waiting for response, they will call an engineer for sure, but don't know when would that be, so for the time being I will set the indoor stat influence to 10 and will see how would that go. I will post the readings few minutes after the pump starts.

I adjusted the influence to 10 and here are the readings after 10 minutes:
GT 1: OFF 42,5 Now 20,5
GT2: -
GT3: Tgt: 51 Now 43
GT4: Tgt: 53,2 Now 33,8
GT5: Tgt: 19,5 Now 20,4
GT6: 44,5
GT8: 44,1
GT9: 36,4
GT10: 8,8
GT11: 6,8
Few minutes after the start additional heat kicked in and tbh I prefer to turn off the power than run the pump on this during the day:/ Still waiting for the landlord's answer.

lovesgshp

Hi Encap.
If you have not turned the pump off, is it possible to give me the readings now?

lovesgshp

Just looking at the data again that you have given.
It looks for some reason that the compressor is not operating, (GT6), as the temperature should be a lot higher, so this is why the additional heat has come on.
There is a possibility the Rego controller unit has developed a fault itself, as the compressor should still be operating.
Re-check all the alarms, back to when the compressor was actually changed.

encap

Unfortunately I turned it off. The readings I gave you were taken down couple minutes after the pump was turned on.

There are no more errors apart from this one aftrr the compressor was chaned.

lovesgshp

Thanks Encap.
Please keep me updated on the outcome, as everything seemed to be moving forward ok.

lovesgshp

Any news Encap? has the sensor been replaced, or is there a wiring fault to it?

Fly100

Read 17 pages with interest, im just above to stat the trip into GSHP. So I have a couple of questions...
Its going to be a new build in Lincolnshire. Insulation will be regs plus 20% id suggest more if its economical.
Ive spoke to a couple of installers so far and they can see a big job coming there way so its all yes yes yes at the min.
Questions...
GSHP powered by solar panels (4 or 6kw using them over 12 months) So that should even out the highs and lows ???


Solar tubes to boost DHW in summer leaving the GSHP doing minimal work ??


Buffer tank connected to a log stove (boiler type) to boost in the winter months ( I get free wood but lifestyle rules it out as full time solution)


My aim is to invest in renewables to get my heating for free and possibly provide my electricity for free also. I understand the peaks and troffs of the seasons, but aim to use my electricity account as a bank. putting in during the summer and withdrawing in the winter.


Thoughts??


Thank you in advance.




FLY

matelodave

I hope you've costed it all out as you could end up with a 20-30 year payback on your investment. It's everso nice to be carbon neutral but it has to be cost effective as well.
Every thing you do will have a cost but won't necessarily save you as much as the first improvement - the laws of diminishing returns comes into play. Once you've got your energy bill down to a low level or even zero spending more money saves you less. Unless you can sell your surplus to recoup the cost over a reasonable period it might not be worth it.


I've just got an EPC in the hope of getting the RHI which is supposed to come in this spring but because I'm quite efficient already, plenty of insulation and I've got an air source heat pump as well the payback for all of the recommendations are over 20 years.
I've looked a solar pv but I wouldn't see the benefit in significantly lower leccy bills as they generate in the summer when the sun shines and I use 70% of it in the winter when it doesn't. My estimate on payback is around 8-10 years based on what I'd get as an FIT and most of it going back into the grid (the EPC reckons it's even worse but doesn't seem to take into account the FIT)