Ground Source Heat Pumps

beardymarrow

lstevensuk said:

Something strange has happened! I thought I would switch everything back on for the week so I can monitor total hours etc. I've  checked everyday and I've not lost a single drop  This thing has been loosing it every week for months and suddenly after switching back off and on nothing!

Wonderful. To me that sounds very much like you were losing it around valves you turned off and on, and the action of turing it off and on again has just moved things ever so slightly. Either that, or the colder weather has caused the ground to contract ever so slightly and take a tiny bit of pressure off whatever underground joint was leaking.

Tomcat106

I’ve been closely reading through this thread to see if it answers a concern I have with my heat pump. I have a IVT Greenline HT Plus C and the Temperature reading – Return radiator GT1 seems completely off :

On 7.5degrees Now 22.3degrees

Is anyone able to clear up what the first valve on the GT1 reading is and why it might be so low?

For reference the other temperature sensor readings are:

Out GT2: 10.5degrees

Hot water GT3: Target 45degrees Now 44.8degrees

Room GT5: Target 17.5degrees Now 20.5degrees

Compressor GT6: 31.1degrees

Heat transfer fluid out GT8: 22.2degrees

Heat transfer fluid in GT9: 22.2degrees

Heat transfer fluid (coil) in GT10: 13.0degrees

Heat transfer fluid (coil) out GT11: 16.1degrees


Thanks!

beardymarrow

Tomcat106 said:

I’ve been closely reading through this thread to see if it answers a concern I have with my heat pump. I have a IVT Greenline HT Plus C and the Temperature reading – Return radiator GT1 seems completely off :

On 7.5degrees Now 22.3degrees

Is anyone able to clear up what the first valve on the GT1 reading is and why it might be so low?

For reference the other temperature sensor readings are:

Out GT2: 10.5degrees

Hot water GT3: Target 45degrees Now 44.8degrees

Room GT5: Target 17.5degrees Now 20.5degrees

Compressor GT6: 31.1degrees

Heat transfer fluid out GT8: 22.2degrees

Heat transfer fluid in GT9: 22.2degrees

Heat transfer fluid (coil) in GT10: 13.0degrees

Heat transfer fluid (coil) out GT11: 16.1degrees


Thanks!

Hi Tomcat,
That first number is the value at which the GSHP will switch on to provide heat. So if the GT1 value falls below 7.5degC it will switch on. That is indeed very, very low :-). As an example my GT1On at the moment is 28.2 (lowest it has been in the last 2 days is about 26) with an outside temp (GT2) of 10.9 and an inside temp (GT5) of 19.0. GT5 and GT2 seems sensible, so I suspect that your heat curve is configured very strangely. The good news is that your actual readings look fine, so it looks like a setting that's wrong, not a fault.
Can you post the values you have for 1.1, 1.2, 1.3 and 1.4 (and 1.11 but this seems unlikely to be a problem). Also see the manual I posted earlier and look at pages 15-17 which describes the heat curve and how your pump uses it to calculate what GT1 values it should use to should switch on and off.

richardc1983

Just seen the below article, there is a target of 600,000 heat pump installations by 2028! Whilst I am all for supporting heat pumps as the main source of heat, until they bring down the cost of electricity per kWh it is not worth the investment and extra running costs over mains gas. Gas is very cheap so if you have a high efficiency condensing boiler running on mains gas then you are better off with that for your heat than going for a heat pump.

A heat pump produces heat more efficiently and cleanly but the electricity costs more to do so: If we consider my own energy tariff that is a current fixed rate deal 1kWh of electricity costs 13p and the equivalent in gas is just over 2p. If we for argument's sake say that a heat pump is 300% efficient meaning for 1kw of energy used (13p) we are getting 3kw heat from it. On my tariff, for it to break even the heat pump system needs to be about 700% efficient.

A modern condensing gas boiler maybe 98% efficient meaning 3kw of heat generated by mains gas is costing about 6p a heat pump is double. Even the standing charge for gas is considerably less at 9p than electricity which is nearly 3 times as much at 23p.

Homeowners being sold heat pump systems over a new modern condensing boiler are being missold if they have mains gas. The number of people I have come across who have ripped out a condensing boiler and put one of these systems only for operating costs to go through the roof only to rip it all back out and start again is crazy.

If you are on mains gas and looking to replace an older gas boiler, fit a new gas condensing boiler, if you don't have mains gas and are using oil or electrical resistive heating (fan heaters, convectors etc) then fit some form of heat pump. Electrical resistive heating is 100% efficient. Meaning that you get 1kWh of heat out for every 1kWh you use, in my tariff example above that is 13p, so a 3kw fan heater will cost you 39p an hour to run whereas a heat pump will produce 3kw of heat for that hour using 1kw of electricity and cost 13p to do so. The equivalent 3kWh from mains gas is approx 6p.

https://www.acrjournal.uk/heat-pumps/uk-targets-600-000-heat-pump-installations-a-year-by-2028/

Tomcat106

beardymarrow said:

Tomcat106 said:

I’ve been closely reading through this thread to see if it answers a concern I have with my heat pump. I have a IVT Greenline HT Plus C and the Temperature reading – Return radiator GT1 seems completely off :

On 7.5degrees Now 22.3degrees

Is anyone able to clear up what the first valve on the GT1 reading is and why it might be so low?

For reference the other temperature sensor readings are:

Out GT2: 10.5degrees

Hot water GT3: Target 45degrees Now 44.8degrees

Room GT5: Target 17.5degrees Now 20.5degrees

Compressor GT6: 31.1degrees

Heat transfer fluid out GT8: 22.2degrees

Heat transfer fluid in GT9: 22.2degrees

Heat transfer fluid (coil) in GT10: 13.0degrees

Heat transfer fluid (coil) out GT11: 16.1degrees


Thanks!

Hi Tomcat,
That first number is the value at which the GSHP will switch on to provide heat. So if the GT1 value falls below 7.5degC it will switch on. That is indeed very, very low :-). As an example my GT1On at the moment is 28.2 (lowest it has been in the last 2 days is about 26) with an outside temp (GT2) of 10.9 and an inside temp (GT5) of 19.0. GT5 and GT2 seems sensible, so I suspect that your heat curve is configured very strangely. The good news is that your actual readings look fine, so it looks like a setting that's wrong, not a fault.
Can you post the values you have for 1.1, 1.2, 1.3 and 1.4 (and 1.11 but this seems unlikely to be a problem). Also see the manual I posted earlier and look at pages 15-17 which describes the heat curve and how your pump uses it to calculate what GT1 values it should use to should switch on and off.

Beardymarrow thanks for the response,
1.1: Temperature increase/decrease= 4.0
1.2: Temp. fine-tune= -1.5degrees 
1.3: Heat curve adjustment= Out 20degrees curve 18.5degrees 
                                              Out 15degrees, curve 21.7degrees 
1.4: Temperature settings heat curve hysteresis= 5.0degrees 
1.11:  Setting the room sensor influence= 5

I have not recently changed the heat curve or room temperature settings, despite this the actual room temperature still remains well above the target temperature. All my radiators have the thermostatic valves fully open. 
It would be great to know if any of these settings are causing the very low GT1 reading I have.

Thanks again!
Tom   

beardymarrow

Tomcat106 said:

beardymarrow said:

Tomcat106 said:

I’ve been closely reading through this thread to see if it answers a concern I have with my heat pump. I have a IVT Greenline HT Plus C and the Temperature reading – Return radiator GT1 seems completely off :

On 7.5degrees Now 22.3degrees

Is anyone able to clear up what the first valve on the GT1 reading is and why it might be so low?

For reference the other temperature sensor readings are:

Out GT2: 10.5degrees

Hot water GT3: Target 45degrees Now 44.8degrees

Room GT5: Target 17.5degrees Now 20.5degrees

Compressor GT6: 31.1degrees

Heat transfer fluid out GT8: 22.2degrees

Heat transfer fluid in GT9: 22.2degrees

Heat transfer fluid (coil) in GT10: 13.0degrees

Heat transfer fluid (coil) out GT11: 16.1degrees


Thanks!

Hi Tomcat,
That first number is the value at which the GSHP will switch on to provide heat. So if the GT1 value falls below 7.5degC it will switch on. That is indeed very, very low :-). As an example my GT1On at the moment is 28.2 (lowest it has been in the last 2 days is about 26) with an outside temp (GT2) of 10.9 and an inside temp (GT5) of 19.0. GT5 and GT2 seems sensible, so I suspect that your heat curve is configured very strangely. The good news is that your actual readings look fine, so it looks like a setting that's wrong, not a fault.
Can you post the values you have for 1.1, 1.2, 1.3 and 1.4 (and 1.11 but this seems unlikely to be a problem). Also see the manual I posted earlier and look at pages 15-17 which describes the heat curve and how your pump uses it to calculate what GT1 values it should use to should switch on and off.

Beardymarrow thanks for the response,
1.1: Temperature increase/decrease= 4.0
1.2: Temp. fine-tune= -1.5degrees 
1.3: Heat curve adjustment= Out 20degrees curve 18.5degrees 
                                              Out 15degrees, curve 21.7degrees 
1.4: Temperature settings heat curve hysteresis= 5.0degrees 
1.11:  Setting the room sensor influence= 5

I have not recently changed the heat curve or room temperature settings, despite this the actual room temperature still remains well above the target temperature. All my radiators have the thermostatic valves fully open. 
It would be great to know if any of these settings are causing the very low GT1 reading I have.

Thanks again!
Tom   

Cool, thanks Tom.
1.1, 1.2, 1.4 and 1.11 look fine to me (1.1 is 5 and 1.2 is +1 on mine, but it's nothing major). Can you get all the other temp values for 1.3? Turn the dial. They should be by default :-
Out 10deg - Curve 24.9deg
Out 5deg - Curve 28.1deg
Out 0deg - Curve 31.3deg
Out -5deg = Curve 34.5deg
Colder than this is not relevant to the current problem (or hopefullty, temps in the UK :-)) but the defaults (for your settings of 1.1 and 1.2) are :-
-10 = 37.7
-15 = 40.9
-20 = 44.1
-25 = 47.3
-30 = 50.5
-35 = 53.7

alastaid

Hi, I have had my heatpump in for a longtime, it replaced an oil boiler, the house has underfloor heating throughout.  As part of the old configuration with the oil boiler the pumps at each underfloor manifold had a thermostatic control to not allow too hot water through to the floor. When the heatpump was installed these were set to not bypass water back to the cold (ie all hot water to the floor), however it looks like they still redirected some hot water back.  So one of the pumps failed and I removed both of these units (one upstairs one downstairs) and replaced them with a straight pump, no thermostatic unit.  This has led to some problems, basically the heatpump is running  for much longer and seems to be using extra heat a lot.  When commissioned GT1 was put on the downstairs side of the return, downstairs is a large concrete slab upstairs is pipes running between joists in aluminium plates, which seems to be the problem.  As I have taken off the thermostatic bypass, the water is returning much colder from downstairs and the heatpump never seems to be able to get it up to the off temp.  I have tried lowering the curve, and fine adjusting but that seems to just make the house colder.   I am after some advice, should I move GT1? I was hoping the system would be more efficient as I am not effectively heating up water and sending it straight back, but obviously have mis-understood something.  Hopefully the drawing makes sense, thanks in advance, Alastair

beardymarrow

alastaid said:

Hi, I have had my heatpump in for a longtime, it replaced an oil boiler, the house has underfloor heating throughout.  As part of the old configuration with the oil boiler the pumps at each underfloor manifold had a thermostatic control to not allow too hot water through to the floor. When the heatpump was installed these were set to not bypass water back to the cold (ie all hot water to the floor), however it looks like they still redirected some hot water back.  So one of the pumps failed and I removed both of these units (one upstairs one downstairs) and replaced them with a straight pump, no thermostatic unit.  This has led to some problems, basically the heatpump is running  for much longer and seems to be using extra heat a lot.  When commissioned GT1 was put on the downstairs side of the return, downstairs is a large concrete slab upstairs is pipes running between joists in aluminium plates, which seems to be the problem.  As I have taken off the thermostatic bypass, the water is returning much colder from downstairs and the heatpump never seems to be able to get it up to the off temp.  I have tried lowering the curve, and fine adjusting but that seems to just make the house colder.   I am after some advice, should I move GT1? I was hoping the system would be more efficient as I am not effectively heating up water and sending it straight back, but obviously have mis-understood something.  Hopefully the drawing makes sense, thanks in advance, Alastair

Hi Alastair,
Yes, the drawing makes perfect sense. The GT1 sensor should be after the join before the 2 manifolds return into the heatpump, though, otherwise it only knows about the return temp from downstairs, not the overall load. Where it is positioned now the GSHP is trying to work out when to be on or off, based on the temp it receives back only from the downstairs (not the mix of the two). Have a look at the diagram in the manual on Page 55, that might help. You could also try adjusting the valves on the manifolds upstairs and downstairs to better balance the flow, so you get more flow through the downstairs loop and less upstairs, or turning the upstairs pump down/downstairs one up.
Beardy

JHen1

My IVT HT Plus C7M G3 has just alarmed with the following error 
HTF (coll) out
I had this serviced Sept 2020. Is this anything to be concerned about ?

JHen1

JHen1 said:

My IVT HT Plus C7M G3 has just alarmed with the following error 
HTF (coll) out
I had this serviced Sept 2020. Is this anything to be concerned about ?

I've acknowledged the alarm but the Alarm indicator is still red