Ground Source Heat Pumps

Strummer22

Re: previous post the temp sensor has been fixed and my GSHP no longer thinks it's Dante's inferno outside.

Several months ago we had a central heating leak in an unknown location and our plumber dosed the system with leak sealant chemical (this or something similar: https://www.screwfix.com/p/fernox-f4-central-heating-leak-sealer-500ml/766pp). I've now been informed that this was a bad idea as it can compromise the efficiency of heat exchangers (although it did fix the leak). 

Our GSHP has a buffer tank - an Elbi Puffer Plus 200 accumulator. I am trying to figure out whether the water from the central heating just stays in the buffer tank and is heated by a coil inside it, or whether the water from the central heating actually goes into the heat pump heat exchanger? I think it's just a tank, no coils, so potentially the leak sealant fluid could affect the heat exchanger.

I am still getting decent DT on the hot water side (4.7°C right now), and a DT of 2.6°C on the brine side. Do those numbers look ok? What should I look out for if the leak sealant is making the system unhappy?

MultiFuelBurner

I mean a leak sealant product is that like one you put in your car cooling when you have a leak and is known as the temporary fix whilst you put the car up for sale before it fails?

I don't like the sound of that at all to be honest but await others response.

Strummer22

Yes hoping for more responses. Our plumber used the sealant as we had no idea where the leak was (no evidence of it anywhere, besides the pressure dropping). The sealant says it won't block heat exchangers... 

Heat pump got an alarm this morning! Low evaporator flow and low brine outlet temp. The evaporator and brine are on the ground loop side but presumably could be affected if the performance of the central heating side of the heat exchanger is compromised? I hope this doesn't get expensive

ChapelBarn

I have an issue with a massive difference in electricity costs between summer and winter, and wanted to understand before this winter whether there is anything I can do to address this. I have just had my bill covering July and August which was around £110/month - for the month of January it was £790 (both figures based on submitted meter readings). A small amount may be due to differences in the price of electricity (my supplier is Octopus) and clearly I have a much greater need for heating in winter - but an almost 8 fold increase seems a huge difference. Unless this is normal for a GSHP?

I have 2 x IVT HT C heat pumps with a buffer tank, all heating is underfloor, room controlled thermostats (generally se to 20), it is a barn conversion with high ceilings to some areas (so large volume), with insulation based on what was required in 2010, which is relatively modern. 2010 is also when the system was installed (commissioned at the time by Ice Energy).

Be interested in any thoughts or advice on this.

matt_drummer

ChapelBarn said:

I have an issue with a massive difference in electricity costs between summer and winter, and wanted to understand before this winter whether there is anything I can do to address this. I have just had my bill covering July and August which was around £110/month - for the month of January it was £790 (both figures based on submitted meter readings). A small amount may be due to differences in the price of electricity (my supplier is Octopus) and clearly I have a much greater need for heating in winter - but an almost 8 fold increase seems a huge difference. Unless this is normal for a GSHP?

I have 2 x IVT HT C heat pumps with a buffer tank, all heating is underfloor, room controlled thermostats (generally se to 20), it is a barn conversion with high ceilings to some areas (so large volume), with insulation based on what was required in 2010, which is relatively modern. 2010 is also when the system was installed (commissioned at the time by Ice Energy).

Be interested in any thoughts or advice on this.

Forget the cost for a minute.

What is your heat loss, how much heat do you need in the worst month and how much do you pay for electricity?

Two heat pumps and a barn conversion sounds quite grand.

£600 a month in the winter for heating doesn't necessarily sound as excessive as you seem to think it might be.

It's not an eight fold increase. You just have no heating in July and August and the most heating in January.

Any large property will face much higher costs from summer to winter than more modest abodes.

beardymarrow

FWIW, Our energy consumption coldest month to warmest is about x4
Jan - 2300kWh
Feb - 2200
Mar - 1700
Apr - 1100
May - 900
Jun - 600
Jul - 500
Aug - 500
Sep - 800
Oct - 1100
Nov - 1600
Dec - 1900

Strummer22

ChapelBarn said:

I have an issue with a massive difference in electricity costs between summer and winter, and wanted to understand before this winter whether there is anything I can do to address this. I have just had my bill covering July and August which was around £110/month - for the month of January it was £790 (both figures based on submitted meter readings). A small amount may be due to differences in the price of electricity (my supplier is Octopus) and clearly I have a much greater need for heating in winter - but an almost 8 fold increase seems a huge difference. Unless this is normal for a GSHP?

I have 2 x IVT HT C heat pumps with a buffer tank, all heating is underfloor, room controlled thermostats (generally se to 20), it is a barn conversion with high ceilings to some areas (so large volume), with insulation based on what was required in 2010, which is relatively modern. 2010 is also when the system was installed (commissioned at the time by Ice Energy).

Be interested in any thoughts or advice on this.

Yes it's normal, to some extent. During the summer the heat pump is not used for space heating, just hot water. Other electric use tends to be lower too, e.g. lights on for less time.

My overall winter usage is 3 - 4 times higher than in summer. It will differ for everyone as it depends how much electricity the heat pump uses compared to other household usage. 

There are ways of saving money on the heat pumps, in particular reducing the flow temperature to the lowest possible that can maintain a comfortable temperature; for underfloor heating this could be as low as 30°C. Turning the thermostat down to 19°C could save you a surprising amount. Manage the house to maximise solar heating and minimise heat loss in winter, e.g. ensure curtains open on sunny days, use draught excluders etc.

I am not familiar with IVT heat pumps but from other users' posts I think they aren't the most efficient, e.g. the compressor is either on or off and can't run at partial load. Does your system have weather compensation? If so it would be worth checking that this is set to something sensible.

 

matt_drummer

Strummer22 said:

I am not familiar with IVT heat pumps but from other users' posts I think they aren't the most efficient, e.g. the compressor is either on or off and can't run at partial load. Does your system have weather compensation? If so it would be worth checking that this is set to something sensible.

 

And they have two of them!

Patrol

My IVT E6 unit started throwing alarms out Q4 last year (high HTF). Finding someone for a GSHP was a lot harder than for gas/oil, and probably ASHP. e.g. people saying they could service but not do repairs or replace parts

So an email then a call with Alto Energy who are 100+ miles away but now the IVT UK distributor. I'd prepared by taking all 40 or so readings in advance and suggested using GT1-GT11 readings first

The Alto chap said GT8-GT9 delta was high, but when I read out the GT11 reading he assured me a new GT11 sensor was needed. He said they could supply and fit but suggested they supply and I get a local plumber to fit it. I said I'd have a go myself and find a plumber if necessary so we sorted out the order

When the sensor arrived it took me about 30 minutes to replace (two wires needed fitting into a plastic clip and the old wires were very difficult to remove otherwise it would have been 2 minutes). Heat pump has been running for several weeks now with no further alarms and house is a more consistent temperature than it ever was. I am left wondering if the sensor had been faulty since 2007 and steadily getting worse!

Posting in case other people with IVT heat pumps require assistance. I found Alto helpful, giving good advice over the phone and happy to discuss the options for resolution

JHen1

Hi My IVT Greenline HT Plus C7M is alarming with a "low pressure switch alarm". I have pressed "Ackn", but it alarmed again shortly after. Looking at the manual there are serveral causes. I can see the expansion vessel is about 60% full (but its about 80% when serviced).