Ground Source Heat Pumps

Fort_2

Geotherm wrote: »

Heat delta is too high on GT10 - 11. Is the flow filter clean after you having the work done? Is the expansion tank 50% full? Have the loop air bleeds been opened after the work, when the pump has been running?

Thank for your reply. They pressure tested it by pumping antifreeze into ground loop. 3 ba. After they fixed the leak they did it again. They checked filters, filed the expansion tank. The only air bleed valve for antifreeze is a automatic bleeding valve, and it was open if i can call so, the cap was removed.
Wat difference in temperatures is regarded as ok on GT10 and GT11.
Thanks

dnichcole

Fort wrote: »

Thank for your reply. They pressure tested it by pumping antifreeze into ground loop. 3 ba. After they fixed the leak they did it again. They checked filters, filed the expansion tank. The only air bleed valve for antifreeze is a automatic bleeding valve, and it was open if i can call so, the cap was removed.
What difference in temperatures is regarded as ok on GT10 and GT11.
Thanks

The temp difference between GT10 and GT11 is calculated by the processor depending on the speed of the ground loop pump. This is manually settable if you take the front panel off and shine a torch inside you should identify the ground loop pump (check photographs in the user manual). Its a standard central heating Wilo pump. I think i have mine on the middle speed of the three available. Fast speed is about 2deg, middle is about 3.6 degs. I have some distrust of the accuracy of the sensors, so going for the middle speed with the larger delta-T will reduce the effect of a + or - 0.4 error between sensors.

lovesgshp

Fort wrote: »

Thank for your reply. They pressure tested it by pumping antifreeze into ground loop. 3 ba. After they fixed the leak they did it again. They checked filters, filed the expansion tank. The only air bleed valve for antifreeze is a automatic bleeding valve, and it was open if i can call so, the cap was removed.
Wat difference in temperatures is regarded as ok on GT10 and GT11.
Thanks

You may need to bleed the circulating pump as well, in case of an air lock there. Temp variables are as quoted in the last post. Suggest you run the ground loop pump on the manual setting within the Installer menu.
Do you also have flow valves you can check?

Fort_2

Geotherm wrote: »

You may need to bleed the circulating pump as well, in case of an air lock there. Temp variables are as quoted in the last post. Suggest you run the ground loop pump on the manual setting within the Installer menu.
Do you also have flow valves you can check?

How do i bleed circulating pump? I can not see any other valves than those near particle filter. there is only two pipes going into the ground from boiler room. Flow and return.

lovesgshp

Fort wrote: »

How do i bleed circulating pump? I can not see any other valves than those near particle filter. there is only two pipes going into the ground from boiler room. Flow and return.

http://www.geotherm.it/Sonde_geotermiche.html

Sorry it's in Italian, but the valves are the brass units just below the collectors on the input side. You may have a completely different configuration.
To bleed the pump, you need to take off the front cover of the heatpump and when the unit is running open the central screw on the pump slowly. If only water comes out you should be ok.

lovesgshp

dnichcole wrote: »

I have the same make of heat pump, IVT from the same supplier Ice Energy. The main tech support guy has been ill for a few weeks over the winter, but prior to that, he gave excellent tech support.

He has allowed me to fiddle with my IVT to tune it quite a lot.
• I have disabled the Immersion heater function, so it has to keep working from the ground. During the month of December 2010, it never needed or used the immersion heater. With solar recharging, the ground temperature never fell below 10º. A year ago, before the recharging, the temperature of the deep ground was 5.0 degrees.
Do you not have DHW disinfection operating?
• The inner water tank of the IVT is scandalously un insulated, because in Sweden, the GSHP is often stored in a garage or outhouse and needs some heat loss to defrost it. If your GSHP is inside the house, you can greatly increase the insulation to the water tank, especially the bottom surface.
Why would you need to defrost the hot water tank as it is a double shell unit?
• I use the IVT's clock function so that it cannot try to heat water during the night. You can use the clock function to do the same for space heating.
If you have UF heating, then IVT recommend a max -1.5C return, or with radiators -4C pump return.
• There is a telecommand function enabling you to turn it off remotely, and I wired this up to a relay so a simple B&Q timeclock can turn the GSHP off and on, without any risk of being on the main electrical supply.
• I now use this telecommand function, connected to a cheap cylinder thermostat attached to the copper wall of the water tank that turns off the water heating to prevent overheating (which is a problem on the IVT model)
Please explain, have never heard of this.
• there are several other things you can do to tune it.
See my blog by googling 'chargingtheearth' for more ideas on this.
By doing all these things, and with a bit of PV on the roof we have managed to make our house better than Zero Carbon on space heating, and by this time next year, that could include water heating too.:j

Hope to see your clarifications on the above

Fort_2

looks like everything is ok now. Bled pump as you recommended, there was some air. Also checked particle filter for antifreeze, it was full of s..t. Plumbers didn't remove it to wash. Temperatures seems to be ok for more than half a day.
Do you now if it is possible to have zone controls with gshp? The system that is fitted in my house has room stats in bedrooms but is not connected to gshp. It is one big loop, that heats all house. Is it possible to heat just bedrooms or just one room. Problem is that difference in temperatures is very big. I have temperature set to 22c on boiler, it is warm downstairs, but upstairs when it is colder outside is only 18-19c.
What is your system like?
Cheers.

dnichcole

Hi, in reply to Geotherm,
Q1.Due to some problem in the controller algorithm, we seemed to be getting pasteurisation every day or twice a day - water going to over 60, and then sometimes the red light on, and the machine stalled. We had the controller replaced, but the same problem persisted. When its doing water it prioritise nthat over heating, so that can also be a problem. so the cylinder thermostat has solved it, we set that to 65 on the outer water jacket,which gets a max of about 58 internally. Re pasteurisation, I should set the cylinder stat to higher every three weeks.
We do not need immersion heater ever as the ground is solar recharged and has never fallen below 10 degrees even after the end of December. So always enough heat down there for doing the job.
Q2. Re defrosting, not the tank, but the engine room around the components. In Finland and Sweden where the deep ground temp is below zero all winter, sometimes -15, the unit working at very low temps, then engine room can ice up. In UK with the unit inside an house, you can vastly improve the insulation around the internal water tank.
Q3. Agree.
Q4. There is a telecommand function with IVT allowing the gshp to be controlled by an external switch, mobile phone or whatever. Can control the entire compressor or just the dhw. there is also a time clock function in the IVT controlling the hours in which it does heating or dhw. Took me three years before I realised this!!!
I have another thing I forgot to mention. The external thermistor sends a command to the GSHP to come on. If you rig up a simple resistor of 4.7 kilohms (17 pence) you can use a 2way light switch to switch between this and the external thermistor to turn the heating on and off at a single touch.
In this way I have reduced the annual fuel consumption of my GSHP from over 6000 to less then 4000 in a single year!

lovesgshp

Fort wrote: »

looks like everything is ok now. Bled pump as you recommended, there was some air. Also checked particle filter for antifreeze, it was full of s..t. Plumbers didn't remove it to wash. Temperatures seems to be ok for more than half a day.
Do you now if it is possible to have zone controls with gshp? The system that is fitted in my house has room stats in bedrooms but is not connected to gshp. It is one big loop, that heats all house. Is it possible to heat just bedrooms or just one room. Problem is that difference in temperatures is very big. I have temperature set to 22c on boiler, it is warm downstairs, but upstairs when it is colder outside is only 18-19c.
What is your system like?
Cheers.

Glad all looks okay now.
What readings are you getting on GT8/9 and GT10/11 when the pump has been running for about 10 mins on the heating cycle?
You can only close down up to max 30% of the underfloor heating, so you can calculate that from the house/room size.
System here is great, constant 19.5-20C all the time.

lovesgshp

dnichcole wrote: »

Hi, in reply to Geotherm,
Q1.Due to some problem in the controller algorithm, we seemed to be getting pasteurisation every day or twice a day - water going to over 60, and then sometimes the red light on, and the machine stalled. We had the controller replaced, but the same problem persisted. When its doing water it prioritise nthat over heating, so that can also be a problem. so the cylinder thermostat has solved it, we set that to 65 on the outer water jacket,which gets a max of about 58 internally. Re pasteurisation, I should set the cylinder stat to higher every three weeks.
You can reset the peak up to 30 days for the disinfection cycle. The unit is meant to prioritise DHW. Over 5 years the electric immersion here, has only run for 24hrs on a 3kw setting.
We do not need immersion heater ever as the ground is solar recharged and has never fallen below 10 degrees even after the end of December. So always enough heat down there for doing the job.
Q2. Re defrosting, not the tank, but the engine room around the components. In Finland and Sweden where the deep ground temp is below zero all winter, sometimes -15, the unit working at very low temps, then engine room can ice up. In UK with the unit inside an house, you can vastly improve the insulation around the internal water tank.
Normally it is just the collector outlet that may ice up, as neither of us live in Finland or Sweden, so are not subject to those extremes.
Q3. Agree.
Q4. There is a telecommand function with IVT allowing the gshp to be controlled by an external switch, mobile phone or whatever. Can control the entire compressor or just the dhw. there is also a time clock function in the IVT controlling the hours in which it does heating or dhw. Took me three years before I realised this!!!
Have used the timer function to reduce DHW and heating return for the last 5 years and it works well. No need for the telecommand if you are in the house all the time
I have another thing I forgot to mention. The external thermistor sends a command to the GSHP to come on. If you rig up a simple resistor of 4.7 kilohms (17 pence) you can use a 2way light switch to switch between this and the external thermistor to turn the heating on and off at a single touch.
Do you not have the internal temp sensor?
In this way I have reduced the annual fuel consumption of my GSHP from over 6000 to less then 4000 in a single year!

I do not know which model you have, heating system or size of house, so could not comment on the usage.