Ground Source Heat Pumps

beardymarrow

lovesgshp wrote: »

Hi Beardy.

4 hrs to heat up the DHW tank? That is exceptional. Check that there is no air in the bleed valves above the pump, they should be automatic, but they may have been closed. With bleeding the air from the DHW tank, that should have improved its heating time, as it is double skinned.
Alarms from last year: May be worthwhile checking the filters again, just as a precaution. 1 inside the pump, and the ground loop one as well.
If you do not have the slope inc/dec temps set then that is no problem. They are just meant to change the heat curve setting up or down.
Condensation, this is normal in colder weather. With your input temp of 0.7 and out of -2,4, then I would expect that. It does point to the pump working a lot of hours though, as you have pointed out.
The heat delta on the DHW may have been changed, as it should start the cycle as soon as it drops 2C below the 51C and shut down 3C above, but will go up a little more.

Right, get ready for a mega update.

I've changed :-
Summer Disconnection to 16. Was 11.
Room Temp to 19 (influence 5). Was 10.6 (and 0)
Temp to 4.5 and fine-tune to 0 (was 3 and -3)

However, when I did, it didn't set the heat curve to the default values that you gave me (or that the sim gave). So I set it back to 3 and -3, and it set the curve to the values I had before (so I don't think anyone has been monkeying with those). I've changed it to 4.5 and 0 anyway, and the values are:-
20 17.9
15 23.6
10 27.2
5 30.8
0 25.8
-5 28
-10 35.2
-15 36.3
-20 37.6
-25 48.2
-30 56
-35 59.6
I've left them like that, as they seem to be the defaults for my Rego 637W.

I've cleaned the filter inside the pump (there was quite a bit of crud in it, but as it's the rad return, I'm assuming won't help my DHW). Don't have a spanner big enough to get the nut off the collector one, so haven't done that one. Will try to get a bigger spanner on Weds and do that one.

I did also notice that the plastic HTF expansion tank had quite a bit less than 1/3rd fluid in it (the liquid only just filled the curved bit at the bottom of the tank), but when the pump was switched back on, it dropped completely to nothing. So, I've topped that up to about half with water. It now stays at that sort of level, even when the pump was switched back on.

When I did switch it back on it went straight into production of DHW. The temps of the DHW were :-
Start - 46 (tgt 51) - It had dropped to 46 as I had the HP off while I was cleaning the filter etc.
15mins - 47.3
40mins - 48.8
1Hr - 50.3 - yes you read it right. 1Hr to raise the temp by 4degrees.
2.5Hrs - 54.9 (Tgt 51)
I don't have menu option 2.4 in I/S to check the DHW hysteresis

My readings were (after the approx 40 mins of DHW production):-
GT6 96.5
GT8 50.6
GT9 59.9
GT10 0.7
GT11 -2.5

HP hours - 13014 (11Hours since yesterday).

I can't find any bleed valves above the pump.

The alarms from April 2013 are all High HTF Delta and HTF Out Max.

lovesgshp

beardymarrow wrote: »

Right, get ready for a mega update.

I've changed :-
Summer Disconnection to 16. Was 11.
Room Temp to 19 (influence 5). Was 10.6 (and 0)
Temp to 4.5 and fine-tune to 0 (was 3 and -3)

However, when I did, it didn't set the heat curve to the default values that you gave me (or that the sim gave). So I set it back to 3 and -3, and it set the curve to the values I had before (so I don't think anyone has been monkeying with those). I've changed it to 4.5 and 0 anyway, and the values are:-
20 17.9
15 23.6
10 27.2
5 30.8
0 25.8
-5 28
-10 35.2
-15 36.3
-20 37.6
-25 48.2
-30 56
-35 59.6
I've left them like that, as they seem to be the defaults for my Rego 637W.
Ok, run with those at the moment. To get back to the full default values would need a factory reset. The temp setting from 5 to -5 are incorrect though, as they should be increasing to the -10 level.

I've cleaned the filter inside the pump (there was quite a bit of crud in it, but as it's the rad return, I'm assuming won't help my DHW). Don't have a spanner big enough to get the nut off the collector one, so haven't done that one. Will try to get a bigger spanner on Weds and do that one.
OK

I did also notice that the plastic HTF expansion tank had quite a bit less than 1/3rd fluid in it (the liquid only just filled the curved bit at the bottom of the tank), but when the pump was switched back on, it dropped completely to nothing. So, I've topped that up to about half with water. It now stays at that sort of level, even when the pump was switched back on.
There should be a pressure valve on the ground loop inlet. When the pump is operating it should be showing about 0.5 bar. Can you confirm?

When I did switch it back on it went straight into production of DHW. The temps of the DHW were :-
Start - 46 (tgt 51) - It had dropped to 46 as I had the HP off while I was cleaning the filter etc.
15mins - 47.3
40mins - 48.8
1Hr - 50.3 - yes you read it right. 1Hr to raise the temp by 4degrees.
That is far too long, With the front of the pump off, can you check the 3 way valve, as it may be sticking. Go into the I/S menu and select manual operation of all functions. 5.3, and check the valve opens and closes properly. ( You will see the lever move back and forth )

My readings were (after the approx 40 mins of DHW production):-
GT6 96.5
GT8 50.6
GT9 59.9
GT10 0.7
GT11 -2.5
GT8/9 are within range. GT10/11, are showing high operating times of the pump, normally associated with low external temps.

HP hours - 13014 (11Hours since yesterday).

I can't find any bleed valves above the pump.
You should have ones that look like these shown in this install. Highest point on the piping.
http://www.geotherm.it/esempi_impianti_progetto_18_geotermia.html#0

The alarms from April 2013 are all High HTF Delta and HTF Out Max.

Keep me updated and the readings from GT1 -11. Better when in heating mode, as the pump steps up to a slightly higher level in DHW production.

beardymarrow

DHW temp update.
Start - 46 (tgt 51) - It had dropped to 46 as I had the HP off while I was cleaning the filter etc.
15mins - 47.3
40mins - 48.8
1Hr - 50.3
2.5Hrs - 54.9 (Tgt 51)
I don't have menu option 2.4 in I/S to check the DHW hysteresis.

I think I know what you mean about bleeding the pumps now. You mean unscrewing the big screw on the actual pump itself a bit? I'll do that tomorrow.

Also, worth noting, perhaps?, is that the collector pipes gurgle when the HP starts up, but then quieten down after a few mins and are now silent. Would that suggest air in the collector system? Would I bleed that by bleeding the Wilo pump in the bottom right of the HP?

lovesgshp

Yes, check both the circulating pumps for air, but also the pressure on the ground loops as above.
The pump air venting valves are the ones shown at the highest level in the picture above the heat pump itself.

beardymarrow

lovesgshp wrote: »

Yes, check both the circulating pumps for air, but also the pressure on the ground loops as above.
The pump air venting valves are the ones shown at the highest level in the picture above the heat pump itself.

Thanks. Will do.

A couple of daft questions (if I may).
I know that I bleed the circulating pumps by unscrewing slightly the big screw on the front of the pump. Do I do that with it running or off?

The pump air venting valves. I have found them. From looking on 'internet, they are automatic floating valve types, with no way to manually bleed them (they just have one little black plastic screw in the top, not two).

Just been to get a 40mm adjustable spanner so I can do the filter on the ground loop as well :-)

lovesgshp

Bleed the circulating pumps with the pump off.
At the moment I am thinking more that the 3 way valve is sticking, maybe between DHW and heating. It should be fully right in heating mode, and fully left in DHW. Please confirm on the manual operation. You will hear and see it move over.
Make sure the valves have been left open (vertical) for the auto air vents to operate and also check the air vent on the ground collectors, as that will normally be closed, so just open it to release any air trapped.

beardymarrow

lovesgshp wrote: »

Bleed the circulating pumps with the pump off.
At the moment I am thinking more that the 3 way valve is sticking, maybe between DHW and heating. It should be fully right in heating mode, and fully left in DHW. Please confirm on the manual operation. You will hear and see it move over.
Make sure the valves have been left open (vertical) for the auto air vents to operate and also check the air vent on the ground collectors, as that will normally be closed, so just open it to release any air trapped.

Hi,
I think you might be right. The 3 way is an ESBE VZA 263. It doesn't seem to go into A fully. I've put a photo of it in A and B below.




Is there any way I can un-stick it without disconnecting the water pipes on it? Or can I manually force it to A (DHW) and switch the heating side of the HP off until I can get it replaced?

Edit: I took the black plastic actuator head off and pushed the metal pin in the valve all the way into the body of the valve (which is what the actuator does to switch to DHW). Now the valve automatically goes all the way to A in for DHW, but only half way back when it's trying to get B for rads. I think that's better for me as I must have more DHW demand than rads at the moment. Should I spray a load of WD40 in there and move the valve needle manually myself a few times to see if I can un-stick it?

When I manually activate the actuator head with it off the valve it goes all the way between A and B properly, so the actuator is fine, but the valve is not.
:End Edit

Pumps all bled. There is what looks like it might be an air bleed on the ground collector. It looks the same as the ones on your picture, but it's got a red cap over the top that says 3 bar on it, so I'm thinking that might be a pressure relief valve, as opposed to an air bleed? There's no pressure gauge on the collectors.

beardymarrow

I think I've got rid of my sticky 3-way (not a sentence I'd ever thought I'd be pleased to say :-) ).

I just pulled the metal pin in and out a few times with a pair of pliers and it did seem to free up as I was doing it.

The valve now goes like this :-


So, that's a lot better. I'm guessing with it stuck between A and B it was sending some water to the DHW and some to the rads, instead of all to the DHW, which would explain why it took so long to heat the water up?

The DHW has just kicked in and it took 9 mins to go from 52 to 54 (which is the temp it switches off at). I don't have the same figures for yesterday, but it took an hour to raise temp 4 degs yesterday (and that was starting at 46, which it must be easier to heat from).

The proof of the pudding will be in the electricity graph and the HP hours, so I'll monitor that overnight (or rather my pet OWL will) and I'll report back.

Regarding bleeding the collector. This is what I've got on the collector. Is that a bleed valve, and if so how do I bleed it?


Thanks a lot

Beardy

lovesgshp

Hi.
Great, then it is that valve causing the problem. I had the same here and the wd40 trick did cure it. Mine has been working OK since 14th Jan, when I first noticed the problem.. Spray the WD 40 in and use the manual control to move it back and forth a few times. If it does not keep operating properly, then unfortunately, you will need to get it replaced.
With the red capped valve on the collectors, that is the pressure release. Is there not another one with just a lever on it, as that is the air bleed? There could have been one put in on the inlet pipe to the pump. Also suprised there is no pressure guage on the install.

beardymarrow

lovesgshp wrote: »

Hi.
Great, then it is that valve causing the problem. I had the same here and the wd40 trick did cure it. Mine has been working OK since 14th Jan, when I first noticed the problem.. Spray the WD 40 in and use the manual control to move it back and forth a few times. If it does not keep operating properly, then unfortunately, you will need to get it replaced.
With the red capped valve on the collectors, that is the pressure release. Is there not another one with just a lever on it, as that is the air bleed? There could have been one put in on the inlet pipe to the pump. Also suprised there is no pressure guage on the install.

Hi,
Thanks for the confirmation.

No, there is no other valve or gauge at all on the ground loop. The run of pipe from the HP to underground (and the return) is very short, and I've traced it all the way and back.

Cheers

Beardy