Ground Source Heat Pumps

lovesgshp

encap wrote: »

Hi lovesgshp,

I hope you can help me with my problem. We recently moved in to a house with gshp. There is ufh with 6 radiators upstairs. The pump is really high on electricity and we would like to cut the costs. It was set for going on only during night time between 00:00 and 8am to take advantage of cheaper tariff.
Not surprised that you are running high electricity bills, with only a 8 hr window for the pump to operate, especially with underfloor included.

Last week I was happy with the indoor temp and decided to change the time heat pump goes on. I reduced that to only 3hrs but I am not sure if I changed the right thing. What I changed was Clock setting HP accord. to clock.(4.1) I then checked the Setting level heat pump +/- (4.1.1) and it is set to -6 degrees, I didn't touch that one, but I think that's too much, manual says up to 3 degrees is ok.
Confused here. Do I understand correctly that you have set the timer in 4.1 to go off from 08.00 to 24.00 daily, plus -6C, which is the return flow temperature? Yes, -6 is far too high.
After a day or so the house was little bit colder and the radiators upstairs are cold, so now I changed that back to the previous settings, waiting to see the results, but my question is what I actually changed? Is it the time when the heat pump goes off or the time when the heat pump produce less heat(-6 in this case)? I'm constantly monitoring my electricity meter and I don't see much difference between these two settings. The installer told me the pump will go on only during the night cheaper tariff for 8hrs, did he mean the additional heat will go on or the pump itself?
The timer setting means the pump will produce less heat, so in your case -6 on the flow temperature. If I am correct, then you probably have a buffer tank installed as well, so this will cool, reducing the heat flow available when the pump returns to normal operating temperature.
To operate solely for 8 hrs, then I would think both the pump and additional heat are coming on. (additional heat after 60 mins of the pump starting)
I know you probably need some more details regarding the pump, I will update that later on, but I'm interested what I changed? Thanks in advance

Firstly, welcome to the forum.
As you rightly say, I do need more information. Simple things first:
1) HT+ model (C or E) series. With "E", DHW tank size? How long has the pump been installed?
2) All readings from menu 3 (GT1 - GT11) under heating operating after 15-30 mins only, not DHW production.
In K2:
3) Menu 7 (7.1-7.4) information.
4) Menu 11 .. Alarms. Last date and frequency. Scroll through the settings.
There will be more, but lets look at the basics first.

akmodi

lovesgshp wrote: »

"Is that possible ? Do' able ? Does it work well ? Tips and Tricks ? Is it worth it (if we can get the extra heat down to 2 hours a day)"

In answer to your extra heat question, bivalentsystem, re gas, this is the answer I had from our design engineers:
"In this case we have to check the wiring diagram and the type of Rego 600: with the earlier series Rego 600 was possible to choose the type of additional heating. With rego 637 instead you could disconnect the internal electrical additional heating to connect a gas boiler, but you can't use both, so in case of emergency you can't do domestic hot water, I suggest to install a small electric element in the DHW tank if possible."

To go back to the original high additional heat use, then my views are these.
1) The room setting @22C is high for a UF system. The norm is 19-20C. This is because a "radiant floor" is far more effective in providing heat evenly. In one of your earlier posts I see that the room temp was at 22.6C.
2) 4.5 on the heat level, is into radiator settings. This may have been set if you have heated towel rails, but would normally have been in conjunction with a buffer tank.
2a) At circa 16 hrs a day for the running hours on the pump, you are far too high, but this could be due to the house temperature setting. Suggest setting room temp influence to level 7, plus reduce to the earlier levels of say 20C.
3) Check the pressures as a earlier post, 1.5bar underfloor and 0.5 ground loop, as these can have a influence on efficiency and running costs.
4) DHW @ 45C is quite low. Suggest you increase it to 48-50C, and from that increase the peak setting to initially 14 days or as we have here 30 days @48C. With high usage, you are very unlikely to get a bacterial infection in the dhw tank, but as always it is up to you to decide.

These are suggestions above and it is entirely up to you to decide on which way you want to move the parameters of the system.

OK am back, I see your suggestions as above.

Will try and get back to you, with the changes suggested (and results). Pressure levels in both the gauges are over 2

Do you need any info currently?

lovesgshp

Hi Akmodi, and welcome back.
The pressure level on the ground loop is quite high, but you should be able to bleed it off a little to say 1 bar on the relief valve. Ok for the heating pressure.
Keep a note of the operating hours in 7.1-7.4 , when you effect any changes. Normally it is around 24 hrs, before the readings show any effect.
Change one setting at a time, as this makes it easier to monitor.
Just keep me updated at the moment, with operating hours and we can see if there is any difference.
Thanks

encap

lovesgshp wrote: »

Firstly, welcome to the forum.
As you rightly say, I do need more information. Simple things first:
1) HT+ model (C or E) series. With "E", DHW tank size? How long has the pump been installed?
2) All readings from menu 3 (GT1 - GT11) under heating operating after 15-30 mins only, not DHW production.
In K2:
3) Menu 7 (7.1-7.4) information.
4) Menu 11 .. Alarms. Last date and frequency. Scroll through the settings.
There will be more, but lets look at the basics first.

Hi lovesgshp,

Here are my readings, the pump was running for about 20min when I took them:
GT1: Off 31.9 Now 20.7
GT2: 5.2
GT3: Tgt 51 Now 51.9
GT4: Tgt 29.4 Now 30.5(I saw also 40 as well as 20)
GT5: Tgt 20 Now 17.3
GT6: 52.3
GT8: 51.4
GT9: 45.7
GT10: 8.7
GT11: 7.6

7.1: 12395h
7.2: 47% DHW 53% RAD
7.3: 1315h

There were few alarms in January this year for Compr. circ. switch. Before we moved in the installer changed the compressor (around three weeks ago). No alarms since we moved in.
The Heatpump is a HT Plus C11M (10,8/13,8kW) Made in Sweden in 2008. Installed probably in 2009. I'm just renting the house, so I don't know the exact date.

Just one more thing, yes, looks like the pump is set to go off between 8am and midnight every day, cause the night tariff is half the price of the day one. You think 16hrs is too much for the pump to be off? Does it take more electricity when going back on after that break? Does the -6C set in the timer affect DHW in any way?

So the pump is working only nights, when it goes off the house is cooled down by another -6C, is that correct? Normally the pump would just stop and that's it, but in my case additional cooling is set in the timer for 16hrs? What happens when I change that to 0? The pump won't go on anyway cause it's set to be off for the day, what's the point of setting this -6C additional cooling thing? I think I do not fully understand the whole heatpump working process. What puzzles me is that radiators are colder in the mornings when the heatpump stops and gets warmer in the afternoon when it is off for around 8hrs or so, only DHW is working, why is that?

Also when I was taking the readings, I saw Stop temp: 31.9 Present 20.4, I assume this is not the room temperature, just the return flow from the underfloor heating system and the radiators, is it?

What about DHW I think it's working 24/7, I read somewhere that the heat for the ufh and the radiators is taken from DHW, so if I switch that off for some time periods during the day or night, does it affect the heating temperature? Sorry for such a long post, but I think I have to learn a lot here.

lovesgshp

Thanks Encap.
Just from the data you have supplied, then it appears pretty obvious the reasons.
The GT1 reading, shows that the pump is having to heat the water by over 11C to achieve the target flow temperature. It will not normally achieve that without the electrical heat starting after 60 mins.
GT5 room temp, also confirms the room has cooled by nearly 3C.
GT10-11. The temp diff in these readings is low, as would expect to be around 3-5C. Possibly the filter requires cleaning.
Answers to other points:
DHW will be 24/7, that is why you are seeing the high % in 7.2. The norm is around 20%.
The 16hr timer reduction is too long, as shown in the GT1 readings and combined with the -6C, you are probably saving virtually nil, due to the electrical heating having to supplement the compressor. That heater is probably set @ 6kw. It is meant purely as a back up unit. The C11 one here has only operated for 34 hrs in 8 years.
The DHW tank has nothing to do with the heating system.

Observations and suggestions:
You are trying to operate the system like a conventional boiler unit, which is not how it is designed. This is why the electric heater is activating, as the compressor cannot raise the flow temperature quickly enough.
Normally, the timer setting is for overnight use to allow the pump a little respite. The setback should be about -1.5C, as this a flow temperature, so then the unit does not have to work so hard to recover.
Suggest that if you want the heating off for so long, ( which I do not recommend), to set at that level. The pump will still operate, but it is probably saving you more than the 6kwh electrical heater being used.
Set the DHW timer to go off from say 22.00 - 06.00.
Look at the DHW peak and set to 30 days.
You now have the operating times as a basis to work on, so if you make the suggested changes, you can monitor the results.
Also, to raise the room temperature by up to 1C can take up to 24 hrs, so you will not get instant results.

Hope all the above helps.

encap

lovesgshp wrote: »

Thanks Encap.
Just from the data you have supplied, then it appears pretty obvious the reasons.
The GT1 reading, shows that the pump is having to heat the water by over 11C to achieve the target flow temperature. It will not normally achieve that without the electrical heat starting after 60 mins.
GT5 room temp, also confirms the room has cooled by nearly 3C.
The room temperature has never been higher than 17C I guess, but the sensor GT5 is place in the hall which usually is colder than the rest of the house. That means the pump never hit the given target, at least since we are there.(may that be one of the reasons for higher bills?) We have our own indoor thermometer in the kitchen and its readings varies between 18-21C.

GT10-11. The temp diff in these readings is low, as would expect to be around 3-5C. Possibly the filter requires cleaning.
Answers to other points:
DHW will be 24/7, that is why you are seeing the high % in 7.2. The norm is around 20%.
The 16hr timer reduction is too long, as shown in the GT1 readings and combined with the -6C, you are probably saving virtually nil, due to the electrical heating having to supplement the compressor. That heater is probably set @ 6kw. It is meant purely as a back up unit. The C11 one here has only operated for 34 hrs in 8 years.
The DHW tank has nothing to do with the heating system.
What would be the best settings for the 235 sq m house then?
How many hours per day the pump should be on? I checked the 7.3 this morning and it says 1320h, comparing with yesterday's reading the additional electric heater was on for 5hrs during the night.

Observations and suggestions:
You are trying to operate the system like a conventional boiler unit, which is not how it is designed. This is why the electric heater is activating, as the compressor cannot raise the flow temperature quickly enough.
Normally, the timer setting is for overnight use to allow the pump a little respite. The setback should be about -1.5C, as this a flow temperature, so then the unit does not have to work so hard to recover.
Suggest that if you want the heating off for so long, ( which I do not recommend), to set at that level. The pump will still operate, but it is probably saving you more than the 6kwh electrical heater being used.
Set the DHW timer to go off from say 22.00 - 06.00.
Look at the DHW peak and set to 30 days.
Can you explain the hot water peak? Manual says very little about it. Thanks
You now have the operating times as a basis to work on, so if you make the suggested changes, you can monitor the results.
Also, to raise the room temperature by up to 1C can take up to 24 hrs, so you will not get instant results.

Hope all the above helps.

Thanks for all the info, all very helpful, Btw: I haven't told you the heat curve readings, it is set to 4, which I've been told is best for ufh with radiators. I will set the DHW as you suggest, but still confused with the heating settings. Maybe for now I will change the DHW and see how many can I save by that. Will update you with the results tomorrow. Thanks!

lovesgshp

encap wrote: »

Thanks for all the info, all very helpful, Btw: I haven't told you the heat curve readings, it is set to 4, which I've been told is best for ufh with radiators. I will set the DHW as you suggest, but still confused with the heating settings. Maybe for now I will change the DHW and see how many can I save by that. Will update you with the results tomorrow. Thanks!

Thanks for the update. I did not want to go into the heat settings, before I had more detail on the actual operation of the pump, as that is a minor point at this moment. Kitchen area will usually be warmer than the rest of the house.
If the pump has used 30kwh of electrical heating then in 5 hrs, then you do have a major use problem even if it is at a low rate.
With a 5C outdoor temperature, it would operate around circa 10hrs a day, the majority overnight, due to daytime temperatures being higher as with heat retention in the building.
The hallway, will probably never get to 20C, with the timer settings that you have at the moment.
Suggest you change to the settings in the earlier post and monitor 7.1 and 7.3. From there we can go on to get you a more economical operation.
Hot water peak: This is when the pump increases the DHW temp by approx 5C. With your DHW set at 51C, then it is not so necessary as the normal heat delta of 2C below and 3C above the set temperature would be adequate. Here we are set @ 48c with peak every 30 days.

encap

I changed the -6C to -1.5C and some time after that I noticed that the pump started(just the pump for the ufh and radiators w/o additional heat) during the day. Also set the DHW to go off between 22-6 yesterday and when I took the electricity meter readings this morning I've noticed that the additional heat was on for 4h instead of usual 5h. The readings from the pump(took them at 7:40 - the pump was still working) from this morning are as follows:

GT1: OFF 43.5 Now 23.2
GT2: 6.7
GT3: Tgt: 51 Now 56.9
GT4: Tgt: 41 Now 39.4
GT5: Tgt: 20 Now 17.5
GT6: 55.9
GT8: 56.9
GT9: 50.6
GT10: 8.1
GT11: 7.2

7.1: 12420h
7.2: 47% 53%
7.3: 1324h

Can you read some more information from this update? Any observations?
My question is when I set the pump to go on between 01:00 and 8:00 and DHW to go off between 22:00-6:00 do these two settings interfere with each other? The other thing is why the pump went on yesterday evening when it was set to go on from 1 to 8 during the night only. Maybe I'm confusing two things here, correct me if I am wrong but the Clock setting HP accord. to clock.(4.1) is for setting the pump to go off or to go on? If I have set 1:00 - 8:00 there does that mean the pump will go on or off during that time? Thanks

lovesgshp

encap wrote: »

I changed the -6C to -1.5C and some time after that I noticed that the pump started(just the pump for the ufh and radiators w/o additional heat) during the day. Also set the DHW to go off between 22-6 yesterday and when I took the electricity meter readings this morning I've noticed that the additional heat was on for 4h instead of usual 5h. The readings from the pump(took them at 7:40 - the pump was still working) from this morning are as follows:

GT1: OFF 43.5 Now 23.2
GT2: 6.7
GT3: Tgt: 51 Now 56.9
GT4: Tgt: 41 Now 39.4
GT5: Tgt: 20 Now 17.5
GT6: 55.9
GT8: 56.9
GT9: 50.6
GT10: 8.1
GT11: 7.2

7.1: 12420h
7.2: 47% 53%
7.3: 1324h

Can you read some more information from this update? Any observations?
What is basically happening now, is that the pump is trying to recover the heat loss from the -6C timer setting over the 16hrs. It will take a few days to settle down from the adjustment.
My question is when I set the pump to go on between 01:00 and 8:00 and DHW to go off between 22:00-6:00 do these two settings interfere with each other?
No, DHW is a completely seperate operation.
The other thing is why the pump went on yesterday evening when it was set to go on from 1 to 8 during the night only. Maybe I'm confusing two things here, correct me if I am wrong but the Clock setting HP accord. to clock.(4.1) is for setting the pump to go off or to go on?
Menu 4.1 is for the time of the pump to either shut down completely, 0 or to provide a reduced return water flow temp, (e.g. -1.5c), but still operate. This is only on the heating cycle.
If I have set 1:00 - 8:00 there does that mean the pump will go on or off during that time?
If you set 01.00 - 08.00 in the timer, then that will act the same as above, as per the 16 hr reduction.
Thanks

Thanks for the updated info.
There still looks to be a problem on the GT10-11 reading. If you can check the filter to see if it is clean it would help. Turn off the pump, close the valve and undo the large Hexagon nut. There will be some coolant escape. You can either take out the filter by removing the circlip, or just have a look to see if it is dirty with a torch.
You will still be getting the additional heat operating for a while, until the GT1 readings get much closer together. Once they have stabilised, then hopefully it should be down to virtually nil.
One other point, will you let me know the room sensor influence from the K2 menu 1.11.
HTH

encap

I guess, they will never stabilise as the temp for heating the radiators was GT1: OFF 43.5 Now 23.2 this morning after 4hrs of additional heat running.
What should I set in the 4.1 then for now? Thanks