Ground Source Heat Pumps

beardymarrow

lovesgshp wrote: »

Just put your basic heat curve adjust break figures into the simulator and these are the base results:
......

These are the return feed temperatures for the heating system.
Is the room sensor not in a hallway?

Thanks chap, that's really helpful. Apologies for the delay in getting back to you. Those settings make a lot more sense than the ones I've got at the moment.

The control unit is a Rego 637W. I've found a pdf which describes what I'm seeing better than the manual I have got (PM'd you the link) (top of Page 22). Maybe it's a slightly newer (or older) software version?

I'm going to leave the heating as it is until 17:00 tomorrow, so I can gauge the difference that bleeding the DHW made on its own over a full day. I checked the bleed valve this morning, and bled a bit more air off (not as much as last night), which worried me a bit, but maybe that's normal. No more air has come out of it since.

Tomorrow I'll change the heat curve break temps, increase the temp to 4.5, set the room temp to 19 and influence to 5

Foolishly I changed more than one thing at once yesterday as I set the DHW to go off between 22:00 and 08:00 (I have reverted this as in hindsight it was a bad idea as it took until after 12:00 for the heat pump to switch off after it had to heat the water back up and my OH was not happy about the lack of hot water), as well as bleeding the DHW, so I've not got a representative day today, plus we've been using a lot of other electricity.

However, setting the DHW to go off between 22:00 and 08:00 did prove that it was the DHW causing my high consumption, as my usage was massively lower between those times.

The room temp sensor is in a hallway, yes.

Have you got a copy of the simulator I can have (assuming it's freeware). I tried to fine it on t'internet, but failed.

Could you also explain how the heat curve break temps and the main heat curve interact? The heat curve break temps seem to override the main heat curve, but only for very specific outside temps?

Apologies the for rambling reply.

Beardy

lovesgshp

Hi.
No problem about the long reply. Have PM'd you with my email so can send you the simulator. It will only work with a windows OS and not a Mac.
Yes, the 637W is a slight variation on the normal 637, but not that much, so leave as is at the moment. Timer setting, would change to about a hour before you get up, as then it has time to get back to temp.
Just another couple of points to look at. Have you got the timers set for the main heating system?
Also can you look into the alarm menu (K2 -11) and let me know what is showing if anything and the dates.
The heat curve is what the pump needs to deliver, controlled by outside air temp, or in conjuction with the indoor sensor. When you look at GT1 in heating mode, this will adjust by each 0.1C as the outside temp changes up or down.
In your case, on he settings you gave, at 5C outside it wanted 24.2C as the flow temp, but at 0C it only asked for 18C, so the colder it got outside the less heat it was asked to produce !!!
Keep recording the GT1-GT11 figures, plus operating hours, as these also help to analyse the situation.

beardymarrow

lovesgshp wrote: »

Hi.
No problem about the long reply. Have PM'd you with my email so can send you the simulator. It will only work with a windows OS and not a Mac.
Yes, the 637W is a slight variation on the normal 637, but not that much, so leave as is at the moment. Timer setting, would change to about a hour before you get up, as then it has time to get back to temp.
Just another couple of points to look at. Have you got the timers set for the main heating system?
Also can you look into the alarm menu (K2 -11) and let me know what is showing if anything and the dates.
The heat curve is what the pump needs to deliver, controlled by outside air temp, or in conjuction with the indoor sensor. When you look at GT1 in heating mode, this will adjust by each 0.1C as the outside temp changes up or down.
In your case, on he settings you gave, at 5C outside it wanted 24.2C as the flow temp, but at 0C it only asked for 18C, so the colder it got outside the less heat it was asked to produce !!!
Keep recording the GT1-GT11 figures, plus operating hours, as these also help to analyse the situation.

Thanks lovesgshp,
The HP took over 4Hrs to get back to temp after the DHW was switched off overnight. Could this really slow heating up explain my high usage? Every hour it has to switch on for 45mins to get back up to temp, when it should only take a couple of mins?

I don't have timers set for the main heating system, no.

The most recent alarms are from April 2013. From memory they were High HTF Delta, but I didn't pay much attention as they were so old. I can check if still relevant?

Thanks for the explanation about the heat curve. I got that bit. What I couldn't work out was why you needed to set the slope (with heat incr/decr) and the delta (with the fine tune), but then also have to set the values at 5deg intervals as well?

I'll email or PM a graph (can't attach here, yet) showing my electricity usage for 24Hrs from last week. This is for the whole house, but clearly shows when the HP is on. Also one for the night of the 29th when the DHW was off (and the next morning when it was on for 4Hrs solid :-(), so you can see the difference.

And, sorry, one more thing. There is a lot of condensation on the collector pipes. They all have pipe insulation round them. Not sure if that's to be expected as obviously they are very cold?

Cheers

Beardy

Cardew

This thread illustrates the criticism made in the Energy Saving Trust reports, namely that the controls are too complex for many people to understand.


My wife ain't thick!(an MA plus lesser degrees) but has not the slightest interest in, or inclination to understand, technical matters.


She simply wouldn't cope with the complexities required to get the heat pump operating efficiently. On/Off, timer, and thermostat are sufficient.


That is in no way meant to be a sexist comment, I suspect the above applies to many people(male and female)!

beardymarrow

Cardew wrote: »

This thread illustrates the criticism made in the Energy Saving Trust reports, namely that the controls are too complex for many people to understand.


My wife ain't thick!(an MA plus lesser degrees) but has not the slightest interest in, or inclination to understand, technical matters.


She simply wouldn't cope with the complexities required to get the heat pump operating efficiently. On/Off, timer, and thermostat are sufficient.


That is in no way meant to be a sexist comment, I suspect the above applies to many people(male and female)!

Hi Cardew,
I do agree, to a certain extent.

I suppose the logic is that if it is set-up correctly (and mine is definitely not set-up correctly), then it doesn't need to be tinkered with. Our old house with normal condensing gas boiler could very easily be controlled, but the temperature fluctuated wildly throughout the day, and that is neither comfortable or efficient for a well insulated house.

I have a degree in electronic engineering and computer science myself, and work in a very technical role, and I have struggled to be honest, so I take your point. My OH would never be able to increase/decrease the temp on ours, either (but then as above, if it's set-up correctly, we shouldn't have to).

I expect the general public would just get it set-up and leave it alone, which is my plan.

So, in summary, yes they are complicated, and too complex for most people to understand, but I don't believe most people need to understand them. They need to get them set-up and then leave them alone (unlike the guy who had the house before me, who clearly didn't understand, but still tinkered) :-)

Of course, I may change my opinion if I can't get mine set-up properly :-)

Beardy

lovesgshp

Hi Beardy.

4 hrs to heat up the DHW tank? That is exceptional. Check that there is no air in the bleed valves above the pump, they should be automatic, but they may have been closed. With bleeding the air from the DHW tank, that should have improved its heating time, as it is double skinned.
Alarms from last year: May be worthwhile checking the filters again, just as a precaution. 1 inside the pump, and the ground loop one as well.
If you do not have the slope inc/dec temps set then that is no problem. They are just meant to change the heat curve setting up or down.
Condensation, this is normal in colder weather. With your input temp of 0.7 and out of -2,4, then I would expect that. It does point to the pump working a lot of hours though, as you have pointed out.
The heat delta on the DHW may have been changed, as it should start the cycle as soon as it drops 2C below the 51C and shut down 3C above, but will go up a little more.

beardymarrow

lovesgshp wrote: »

Hi Beardy.

4 hrs to heat up the DHW tank? That is exceptional. Check that there is no air in the bleed valves above the pump, they should be automatic, but they may have been closed. With bleeding the air from the DHW tank, that should have improved its heating time, as it is double skinned.
Alarms from last year: May be worthwhile checking the filters again, just as a precaution. 1 inside the pump, and the ground loop one as well.
If you do not have the slope inc/dec temps set then that is no problem. They are just meant to change the heat curve setting up or down.
Condensation, this is normal in colder weather. With your input temp of 0.7 and out of -2,4, then I would expect that. It does point to the pump working a lot of hours though, as you have pointed out.
The heat delta on the DHW may have been changed, as it should start the cycle as soon as it drops 2C below the 51C and shut down 3C above, but will go up a little more.

I might be jumping to conclusions (with the DHW taking 4Hrs), but the HP was defo on solidly from 08:00 (when the DHW came back on) until 12:11. Based on how warm it was yesterday and the fact that my summer disconnect is set to 11deg I can only assume it's all DHW. It certainly was every time I went out to check it.

I'll check the DHW delta this evening (and the filters). I'm guessing this is the DHW hysteresis on I/S 2.4?

Cheers

lovesgshp

Yes, dhw delta is in I/S 2.4.
We do need to find out when the pump is starting the heating cycle. The 11C cutoff is probably letting everything cool down too much, and it is working harder to recover heating temperature.
With the DHW you need to look at the current temp and then time when it switches on to switch off.
Do you know what temps are outside before 8.00 a.m.?

lovesgshp

Cardew wrote: »

This thread illustrates the criticism made in the Energy Saving Trust reports, namely that the controls are too complex for many people to understand.


My wife ain't thick!(an MA plus lesser degrees) but has not the slightest interest in, or inclination to understand, technical matters.


She simply wouldn't cope with the complexities required to get the heat pump operating efficiently. On/Off, timer, and thermostat are sufficient.


That is in no way meant to be a sexist comment, I suspect the above applies to many people(male and female)!

I agree with the comments Cardew and it is a factor that if the client is not asked for what they prefer on the initial setup of the pump, then that can cause a multitude of problems.
They can be complicated, but after the installation then not so much. Most of the time it is just a couple of minor setting changes, which are fairly straightforward.
In the case of Beardy, it looks like the previous owner has gone over the top with some of them, so will try to help resolve as best as I can from here.

beardymarrow

lovesgshp wrote: »

I agree with the comments Cardew and it is a factor that if the client is not asked for what they prefer on the initial setup of the pump, then that can cause a multitude of problems.
They can be complicated, but after the installation then not so much. Most of the time it is just a couple of minor setting changes, which are fairly straightforward.
In the case of Beardy, it looks like the previous owner has gone over the top with some of them, so will try to help resolve as best as I can from here.

I could be charitable and say that the previous owner's life-style and therefore requirements differ from mine. In reality I suspect he was a numpty who didn't know enough to know he didn't know enough :-)