GSHP - EcoForest - High Energy usage

didmatt

Hi,

We have recently moved into a property in the spring and have been struggling to understand if our EcoForest GSHP is running/configured correctly. Currently it has been using 1.6KW an hour to heat the buffer tank on the heating circuit and struggling to stay around the setpoint. To the point when we turned on the heating pump this morning to see if the rads feel warm (after 18hours of the heat pump trying to get the buffer tank up to the set point) within 5-10mins the butter tank temp drops back down, thus rads become lukewarm.

Any ideas welcome. As far as we can work out from the Ecoforest display panel on the unit we have weather compensation turned on. 

Thanks
Matt.

Reed_Richards

It doesn't sound at all like your heat pump is running correctly; I suggest you find a service engineer who is familiar with your model of GSHP.    

FreeBear

Radiators with a heat pump should never get roasting hot like you would get with a gas/oil boiler. Luke warm is what I would have expected. As long as the property is being heated to a comfortable level without consuming excessive amounts of electricity, it is running "normally". However, heat pumps are a "slow & steady" form of heating, so it takes a lot longer for a house to warm up - If you are used to gas/oil heating with 30-60 min heat up times, you are in for a bit of a culture shock.

That said, I'm in agreement with @Reed_Richards - Get an engineer in to do a service and run through with you how to tune & run the system for best efficiency or performance.

Strummer22

didmatt said:

Hi,

We have recently moved into a property in the spring and have been struggling to understand if our EcoForest GSHP is running/configured correctly. Currently it has been using 1.6KW an hour to heat the buffer tank on the heating circuit and struggling to stay around the setpoint. To the point when we turned on the heating pump this morning to see if the rads feel warm (after 18hours of the heat pump trying to get the buffer tank up to the set point) within 5-10mins the butter tank temp drops back down, thus rads become lukewarm.

Any ideas welcome. As far as we can work out from the Ecoforest display panel on the unit we have weather compensation turned on.  

Thanks
Matt.

Hi, welcome to the forum. I have an EcoForest GSHP so hopefully can help, but I agree that finding an engineer to service the pump would be a good idea. A few questions:

1. Which model is it?

2. Were you left a copy of the manual? If not, it's probably this one: https://ecoforest.co.uk/assets/files/2018_05_15__User_EN.pdf?rnd=

3. Does it have a control panel like the one in section 3.1 of the manual above? The menus aren't that intuitive to navigate but the manual tells you how to do it.

Assuming you have that control panel, can you tell us a few things -

4.Has it provided adequate hot water all summer? What is the hot water temperature set point? Check that it hasn't just been relying on a built-in immersion heater; you'd probably know if it has because that would use shedloads of electricity. 

5. It sounds like the heat pump can't heat the buffer tank even when the central heating is off. What is the set point and how close to that set point does the temperature get?

6. Check under the 'schedule' menu to see if the previous owner set a limit on the compressor speed; I set mine to 50% as the heat pump is rather oversized (reducing compressor speed helps efficiency) and I manually increase it during very cold spells. If set very low this could explain why it struggles. E.g. if the max electricity consumption you see is 1.6 kW, that might equate to 7 kW of heat; OK if you've got a 7 kW model, but not if your house is big and you've got a 22 kW model. 

6. If you leave the central heating running for longer than 10 mins, does the buffer tank temp recover? It's normal for buffer tank temp to decrease after central heating comes on as all the cold water that was in the rads and heating circuit begins to circulate. The heat pump then has to heat that up in addition to the water in the buffer tank. 

didmatt

Thanks for the reply. 

1) Its an ecoforest geo 5-12

2) Thanks - yes we have all the manuals which is useful!

3) It has a LCD control panel on the top of the unit.

4) It has been providing hot water as required to heat a hot water tank throughout the summer.

5) We have been trying differently set points and whilst it has reacted set point to heat the butter tank with the Central heating off, it is unable to meet any set point when we turn on the central heating.

6) We aren't aware of any limit being set and haven't seen anything being set within the menus. 

7) We have left the central heating on for over 6 hours and throughout that time it is unable to recover the temps in the buffer tank. 

Strummer22

didmatt said:

Thanks for the reply. 

1) Its an ecoforest geo 5-12

2) Thanks - yes we have all the manuals which is useful!

3) It has a LCD control panel on the top of the unit.

4) It has been providing hot water as required to heat a hot water tank throughout the summer.

5) We have been trying differently set points and whilst it has reacted set point to heat the butter tank with the Central heating off, it is unable to meet any set point when we turn on the central heating.

6) We aren't aware of any limit being set and haven't seen anything being set within the menus. 

7) We have left the central heating on for over 6 hours and throughout that time it is unable to recover the temps in the buffer tank. 

Thanks for coming back with these responses. If it can heat the hot water, and the buffer tank when the heating's off, then the heat pump is working OK. I can't really fathom a reason why it then can't manage when the central heating is on, unless the pump is significantly undersized for the property; given the weather is pretty mild at the moment that shouldn't even be an issue anyway.

How big and well insulated is your property? 

How close to the set point does the temp in the buffer tank get? Can you give an example of the set point and actual temperatures you're getting when the central heating has been on for a while? 

The maximum heat output from your heat pump is 12 kW but the max electricity consumption you've seen when heating the buffer tank is 1.6 kW. It almost certainly isn't producing 12 kW of heat - that's a COP of 7.5. A COP of 5 or 5.5 is more likely at this time of year (warm brine, low flow temps as it's not cold outside). 

What's the electricity consumption when it's heating the hot water? 

BTW the compressor limiter is 'night mode' so if it's on a little snoozy face appears on the LCD screen.

didmatt

Hi,

Thanks for the responses and information.

How big and well insulated is your property? 
Its around 175sq meters. 

How close to the set point does the temp in the buffer tank get? Can you give an example of the set point and actual temperatures you're getting when the central heating has been on for a while? 

We set the target to be 40c but only got to actually 22c and dropped to 20c. 

What's the electricity consumption when it's heating the hot water?
No more than 3kw and it's around the same if we use the immersion.

Curious to know what pressure is your loop operation at? We've noticed ours is around 0.5 bar which seems low from what we can research. 

How long does it take on average for your buffer tank to heat up ? From a cold start? Be interesting to know as running the heat pump like we have waiting for it seems a very long time...

Strummer22

A 12 kW unit will probably be fine for 175 sqm if the property is well insulated.

The ground loop brine pressure should be around 1 bar (0.7 - 2 according to the manual). It needs topping up, but I don't think that's the cause of your issues. If you get a service engineer in they will top it up for you (make sure they do). If it falls again at anything other than a very slow rate, either there's air moving around in the ground loop, which should be bled off, or there's a leak. Same for the central heating, 1-1.5 bar is good, but you can top that up yourself if it's low.

From a cold start my buffer tank would take maybe 20 mins to reach 40C with the central heating off. 

Your compressor appears to work fine given the 3 kW consumption when heating the hot water tank. The problem is with some control aspect of the central heating; could be mechanical like a valve, more likely a circuit board or sensor malfunction. You'd be best to get an engineer in. Do you know who installed the system? If a reputable company they're probably the best to contact in the first instance.

From the information menu, when the heat pump is struggling to heat the buffer tank with the central heating on, what are the brine and production inlet and outlet temps? 

didmatt

Once again thank you for the information, its really useful to understand what to expect or how its being used as we find it difficult to find real world examples! We are lucky to know the firm who have installed it originally and we've asked them to come and service the HP and look into why its not performing how we understand a HP to operate.

From the information menu, when the heat pump is struggling to heat the buffer tank with the central heating on, what are the brine and production inlet and outlet temps? 

Strummer22

The brine and central heating pumps (the central heating pump internal to the heat pump, not the one sending water round the radiators) are running at very low % of max. The DT is low too, mine is usually 3-4C on the brine side and 4-5C on the heating. Maybe the filter on the central heating side needs cleaning. That would also be done as part of the service.

Please update after the service to let us know if they found out what the issue is and if it's been resolved, this will helpful for me and others if we run into similar problems in the future.

Strummer22

Thanks for the update. It's a bit unclear whether it's a suspected or confirmed refrigerant leak. I'm a bit surprised the heat pump didn't just throw out an error message and stop working!

Presumably the source of any leak has been/will be fixed too. There's little point topping up the refrigerant is it's just going to leak out again.