Ground Source Heat Pumps

lovesgshp

Turn the pump valve inside the casing down to 2 as a test.
There may be a stuck mixing valve in the circuit causing the problem, but it is a process of elimination at the moment.

Another thought, before you do the above. Turn the DHW temperature up so that it switches on. When it stops there should be a surge to the heating system. You will be able to check it by holding the pipes on the top of the pump.

DeeWestern

Thanks! The alarm went off again with all the radiators open, so the internal pump has been turned down to 2.

lovesgshp

GT1 Off 34.8 Now 31.7
GT2 12.5
GT3 Tgt 52, Now 55.6

Just looking again at one of your previous posts. Had the DHW just switched off before the heating cycle?

DeeWestern

lovesgshp wrote: »

Another thought, before you do the above. Turn the DHW temperature up so that it switches on. When it stops there should be a surge to the heating system. You will be able to check it by holding the pipes on the top of the pump.

Sorry, I replied before you added this edit. Which pump and pipes are we talking about - still the one inside the casing?

The alarm came back on 30 minutes ago with the pump in the casing on 2, so I have put it back to 3.

The external pump is attached to one of the two pipes that comes out of the 'Flow Heating' connector on the cylinder. I felt it vibrating and it was warm to touch.

lovesgshp wrote: »

GT1 Off 34.8 Now 31.7
GT2 12.5
GT3 Tgt 52, Now 55.6

Just looking again at one of your previous posts. Had the DHW just switched off before the heating cycle?

Again, I'm not sure what the symbols mean, but if I assume that the tap symbol is DHW and the snake going in the house is heating, then these readings were taken when only the heating was on. DHW regularly comes on so it wouldn't have been too long since it switched off but I can't give you an exact time. Do you want it measured again?

lovesgshp

Thanks.
Yes tap symbol is DHW.
The pipes I was talking about are out of the top of the heat pump. One will go to the DHW cylinder and the other to the buffer tank.
The pump is the one inside the casing.
I am beginning to think that this a valve problem. When you went to the manual operation of the 3way valve, was there any indication it was actually switching over fully?

lovesgshp

Will you cut your DHW setting to 48C, then monitor it when the heating is on to see if it increases?

DeeWestern

I think I may have misunderstood the symbols - I think the snake going in the house might be GSHP operating, as it was lit with the tap, but when I pressed info it said 'Hotwater Mode, Heat Pump Only'.

I've set the target to 48 degrees, will leave it for a couple of days and see what happens.

With just the snake light on (before I changed the target temp), my readings were,
GT1 Off 38.1, Now 33.5
GT2 8.8
GT3 Target 52, Now 57.2
GT8 47.3
GT9 33.8

The cylindrical water tank is for storing heating water, the big worcester box is for storing tap water (and also had a link to repressurise the heating circuit, currently at 1 bar).

I operated the 3 way valve manually with the cover off, and it seemed to work - it twisted slightly and made a noise for a few seconds as it activated.

As requested, I ran the hot water - which triggered hot water to come out of the right pipe on the 3 way valve. I then pressed the power button on the boiler, and the valve switched its setting and the left (heating) pipe warmed up a bit.

Would the fact the hot water is consistently above target be linked to the delta GT8/9 error, or are these 2 totally different things?

lovesgshp

DeeWestern wrote: »

I think I may have misunderstood the symbols - I think the snake going in the house might be GSHP operating, as it was lit with the tap, but when I pressed info it said 'Hotwater Mode, Heat Pump Only'.
That is normal, the snake is the GSHP working, the tap shows it heating the DHW

I've set the target to 48 degrees, will leave it for a couple of days and see what happens.
Monitor that as often as you can for the temperature, especially when heating is operating.

With just the snake light on (before I changed the target temp), my readings were,
GT1 Off 38.1, Now 33.5
GT2 8.8
GT3 Target 52, Now 57.2
GT8 47.3
GT9 33.8

The cylindrical water tank is for storing heating water, the big worcester box is for storing tap water (and also had a link to repressurise the heating circuit, currently at 1 bar).
OK

I operated the 3 way valve manually with the cover off, and it seemed to work - it twisted slightly and made a noise for a few seconds as it activated.
Still thinking about this!!!

As requested, I ran the hot water - which triggered hot water to come out of the right pipe on the 3 way valve. I then pressed the power button on the boiler, and the valve switched its setting and the left (heating) pipe warmed up a bit.
You should have got a burst of very hot water at the switchover, 55c to 35c is quite a difference.

Would the fact the hot water is consistently above target be linked to the delta GT8/9 error, or are these 2 totally different things?

The GT8/GT9 delta is linked. The more I think about it, the more I think it is the 3 way valve, but obviously I could be wrong.

Can you let me know what 2.2 is set at. ( Peak Hot Water )?

DeeWestern

The left pipe did indeed warm up a lot after the boiler was switched off, but took about 30 seconds to do so. Will let the DHW tank cool down and then keep an eye on the temps.

lovesgshp

DeeWestern wrote: »

The left pipe did indeed warm up a lot after the boiler was switched off, but took about 30 seconds to do so. Will let the DHW tank cool down and then keep an eye on the temps.

You should have got a fairly instant heat increase as the DHW shut down, not 30 secs.