Ground Source Heat Pumps

beardymarrow

lovesgshp wrote: »

Hi Guys.

Beardy.
You have probably got a 2nd circulating pump for the radiator system. What you need to do is turn that to maximum speed and reduce P1 back to its previous setting. Let me know how the deltas change. It is quite possible that you need to balance the flow through the rads after the mixing valve has been fitted.
Leave P2 as it is at the moment.

Apologies for the late replies, but have been out most of the morning.

Will do. P1 was set to 2 originally and I upped it to 3 this morning. My rad pump on the 2nd (top) floor was set to 1, so I did up that to 2 as well this morning. Will bang my 2nd floor pump up to 3, and set P1 back to 2.

One thing I did notice is that the P1 pump is on the feed side between the heat pump and the split between the UFH and the rads, not after the split. The UFH has its own pump as well (set to Speed 1). Is that normal, or should P1 be after the UFH has been split off?

Thanks

lovesgshp

There seems to be something wrong somewhere with the circulating pumps. If you look on P55 of the manual, there should be a P4 pump for a mixer valve system.
Also have a look at P67 regarding the heat flow ( next to last paragraph), as it seems to be what is happening with your system.

beardymarrow

lovesgshp wrote: »

There seems to be something wrong somewhere with the circulating pumps. If you look on P55 of the manual, there should be a P4 pump for a mixer valve system.
Also have a look at P67 regarding the heat flow ( next to last paragraph), as it seems to be what is happening with your system.

Hi, Yes there is a P4 pump. Sorry, I wasn't clear. That's what I meant by the UFH having its own pump.

P67 is interesting. You're right it does seem to be what is happening here, and therefore upping P2 would be counter-productive, so thanks for pointing that out. It also sort of makes sense that I've got reduced flow in the heating system, as now there is a mixer valve, there will be less flow in the heating loop as the UFH is re-circulating some of the water back within itself. I'll update later once I've got access to the system and had a "play".

beardymarrow

No crud in the filter.

So before I made any changes :-
P1 was set to 3 (Rad Pump)
P2 was set to 3 (Heat Fluid Pump)
P4 was set to 1 (UFH Pump)
2nd floor pump was set to 2

I upped the 2nd floor pump to 3 and it didn't make much difference, so I set P2 down to 2 (I know you told me to leave it as is, sorry!), so that like Page 67 says I've got higher flow over the heating system than the heat pump now. The GT8/GT9 Delta has dropped to 9.6. It had gone as high as 25 before that.

I'll keep my eye on the stats tonight.

Thanks (again) so much for your help!

Edit: Oh and the High HTF delta alarm has gone!

lovesgshp

Great, just monitor it for a while. Delta looks ok

Patrol

Sounds like you are making progress Beardy.

Thanks for info.
Supplier suggests faulty soft start. Visit booked 1st week of Feb, price of new soft start plus labour was given but I forgot to ask if that was with VAT. Asked about price of compressor, eyes started to water so hoping it's not that.

At the quoted prices the 5 year warranty looks like a sensible proposition as it also includes an annual inspection. My system is now 8 years old so probably false economy to go without warranty.

Question, more out of curiosity than anything else. When I tried starting it, MB1 tripped after 15 seconds but the compressor made no noise or movement that I recall. If MB1 was faulty would the compressor have started to do something in that time?

beardymarrow

Patrol wrote: »

Sounds like you are making progress Beardy.

Thanks for info.
Supplier suggests faulty soft start. Visit booked 1st week of Feb, price of new soft start plus labour was given but I forgot to ask if that was with VAT. Asked about price of compressor, eyes started to water so hoping it's not that.

At the quoted prices the 5 year warranty looks like a sensible proposition as it also includes an annual inspection. My system is now 8 years old so probably false economy to go without warranty.

Question, more out of curiosity than anything else. When I tried starting it, MB1 tripped after 15 seconds but the compressor made no noise or movement that I recall. If MB1 was faulty would the compressor have started to do something in that time?

Hi Patrol,
If the Compressor didn't try to start, then it doesn't sound like that is tripping MB1, so that would indeed suggest that it's the soft start. Soft starts are not cheap, but I guess a hell of lot cheaper than a compressor, so fingers crossed :-).

lovesgshp

I completely forgot about the soft start, as most of the installs here are 3 phase, which do not need it... apologies
With MB1 tripping before the compressor start is probably due to the diagnostics with the Rego unit, making sure all is ok b4 it lets the pump start to avoid any damage.

beardymarrow

Afternoon, Me again.

All still going well with the GT8/GT9 delta so that's good.

Now I've got the mixer valve fitted I can run the curve higher without sweltering in the UFH part of the house. However, it has raised another issue, which is that basically GT1 never goes above 38ish unless add heat kicks in. It basically sits at 38ish with the compressor on solidly and GT1 not changing. That doesn't seem right to me, it should be able to achieve higher than that without resorting to add heat?

Graph attached (the period between 20:00 and 04:00 is indicative).
What do you think?


Link to bigger version

PS Ignore the GT1 On and Off Values dropping at 21:00. I changed the curve and inside temp at that time.

lovesgshp

Hi Beardy.
If the additional heat is activating, then the 60 min countdown has activated. You could try altering it to 2hrs, or alternatively turn off the add heat as a test to see what temp the compressor is reaching.
What is the room sensor influence and temp?
Can you overlay the outside temperature on the graph?