Ground Source Heat Pumps

lovesgshp · 8 September 2018 at 10:37PM

Just another thought johnoldhouse. Can you give me the readings from GT1 to GT 11 in heating mode only after approx 10 minutes of operation.

JHen · 9 September 2018 at 9:29AM

After filling this up with water on Friday it has dropped by 4" today so there is about 3" left - do i just keep topping this up with water?
There is another red tank with a pressure gauge and when running (hot ware mode) it reads 1bar.

What happens if this runs out ? Where is it going ?

lovesgshp · 9 September 2018 at 10:31AM

JHen. Just keep topping it up at the moment. Presume you are doing that with the pump running.
Check joints on collectors and inside the pump in case there is a leak. 1 bar is ok.

JHen · 9 September 2018 at 11:00AM

Cool. Last time I filled it it was not running. Is that an issue. How do I force it to run or is it a case of waiting ?

lovesgshp · 9 September 2018 at 11:31AM

Go into the service menu and then manual operation of all functions. You can start the ground loop pump from that menu.

johnoldhouse · 9 September 2018 at 3:04PM

I'll have to run force it into heating mode only this evening but the Hot water mode readings after 10 minutes of running last night were
GT1 35.2
GT2 14.6
GT3 Target 42 Actual 43.2
GT5 Target 18 Actual 24.5
GT6 Normally about 70C
GT8 46.8
GT9 36.4
GT10 8.5
GT11 6.5

Radiator Return Target was 10C which is what I would expect with curve slope =4 and -2.5 fine tune (not yet setup really just first guess).

The Return radiator sensor GT1* (the * refers to the location referred to in the installation manual although it is a bit vague exactly where it should be) and in my case is on the radiator return back into the heat store.

Last night I set the Summer Disconnect Temp to 16C (was 10C) and it appears that the radiator pump (G1) is controlled by this temperature and that the Radiator Return Target temp and the radiator actual return temp has no effect. Is that correct or is something amiss with the control system?

The HP ran twice during the night to top up the hot water, which is shared with the heating circuit, and shut down when GT8 reached 52C and GT9 was 42.4

I know I am using the system in rather a strange way but we don't use much hot water and are used to just using what is left over from the heating. I noticed from your previous postings that my GT10-GT11 difference is a bit low but I am using a fast lowing stream rather than a ground loop and wonder if this might make a difference. Checked the filter which was clean but of course I don't really know the state of the evaporator heat exchanger, might this need to be back flushed?

lovesgshp · 10 September 2018 at 8:00PM

Hi again.
GT1 is on the return flow as you say. Move it to within 50cms of the downpipe back into the pump, not into the heatstore.
16C setting for cutoff is ok, but you may consider 18c as winter approaches. Are you operating with a internal room sensor as well? If so, what is that set at for influence?
The operating figures seem fairly reasonable, although gt8/9 are close to limits. Gt10/11 are low, but this could be caused by the fact you are using a fast stream for the input, so low heat recharge. Maybe check the pump speed for that.
Check the alarm menu in full as hopefully the previous owner did not know how to clear it and also the operating times and % use.

johnoldhouse · 12 September 2018 at 5:30PM

I have slowed the ground loop pump and now the delta is 3 degrees. Heat circuit pump is at highest setting. I have a heat meter on the output and it says the flow is 0.26 l/s so right on the lower limit. Will have to find out why as the piping to the heat store is not very long and that should be the only restriction.

I think I understand what the control system is doing now. The radiator pump runs continuously and by doing so provides an average of the temperature in the house so that the HP can run when it drops below the target temperature based on the outdoor temp and curve selected. This is not very helpful for me as I am attempting to share the Hot water and buffer tanks functions to use off peak electricity and DHW being a low priority. If the radiator pump runs all the time I will always be dumping heat to the radiator even if not require.

I found a manual for a newer IVT (Worcester) heat pump which shows the T1 sensor located in the buffer tank with four ports arranged the same way I have done it. This might work better and for now I am going to use this setup and use my old room thermostat to control the radiator pump. I think this should be OK as, as it gets colder the HP with increase the stored hot water temp available to the radiators. Bit of a hybrid control system but happy to give it a go.

Checked running hours and they are 30400, 25% DHW, 44% DHW Extra Heat, not sure if this means its on its last legs? I think the HP was fitted in 2007 as this is the earliest error logged. I found a number of HTF under Temp messages in May 2015 which would confirm information I got that the reason the HP was taken out was the ground loop was crushed by tons of earth being delivered and owner gave up and had a oil boiler fitted.

lovesgshp · 12 September 2018 at 6:02PM

Hi John.

Yes, you are at the minimum flow rate.
You can stop the heat circulating pump and only make it start with the compressor from the I/S menu.
I have a copy of the full installation manual if yours does not cover everything and also a simulator for the Rego 600. (This is a exe file ).
If you want to send me a PM with a email address I will send them to you.
I would very much doubt the ground loops were crushed by tons of earth, as they tons put on them normally. Depending on what type they will usually be expected to last well beyond the heat pump life. The ones we use here are expected to have a life of about 100 years.
Just a few other minor points:
Have you insulated the input lines into the house?
Check the electrical heater is set to maybe use only 3Kw of power as from the figures it looks like the pump is having to use that to boost the supply. As you are using a E11 tariff you could be causing excess operating costs.

ChapelBarn · 27 October 2018 at 10:15AM

I had a GSHP (2 x [FONT=&quot]Greenline HT+ C11 (Three Phase)[/FONT]) installed by a plumber in 2009, which was then commissioned by Ice energy. We had Ice Energy back after a few months as we had some issues with the electricity consumption - following that everything seemed fine until May this year when we started getting intermittent LP and Superheat alarms. We had a company come out who diagnosed "oil restriction in the evaporator...and TEV (TEU?) not adjusting". This was rectified, but resulted in HTF Delta alarms - and so we they recommended further work to have the units stripped, flushed and inhibitor replaced and a magnetic filter adding to remove dirt. We had this done as a second visit.

Since this work was completed we have now had even more alarms - HTF Delta, Electric Cassette and HP return - these are occurring on an almost daily basis. I think they generally re set automatically, with the exception of the Electric cassette which required manually re setting. So having spent a fair amount of money on two visits, I appear to be no better then when I started.

Having contacted the company that did the work, they claim it is not their issue and the result of incorrect sizing of the internal pumps and incorrectly sized pipes, which is causing a restricted flow, both of which need replacing - with a caveat that this might (or might not) resolve the issue. I am also not sure why this was not evident as an issue in the previous 7 years.

I am not really sure whether to go ahead with this and so would appreciate any guidance.

Ground Source Heat Pumps

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