Ground Source Heat Pumps

beardymarrow

lovesgshp wrote: »

The deltas are fine.
Compressor is obviously working to a higher temp for hot water production.
If you have not done so, check for any alarms, as there could have been resets.
Confirm that all circulating pumps are working.
Would you also supply the graph for the 28th, which was before the problem occured.

Hi,
Yes all circulating pumps are on and working fine. There haven't been any alarms since the GT8/GT9 delta ones a few days ago.
I'm not sure the problem has occurred, or always been there (since I moved in). Until I got the mix valve I wasn't running the curve high enough for it to need to hit these sort of GT1 temps otherwise the UFH part of the house was too hot. I've looked back through the stats and I've never hit higher than 38.4 on GT1 (unless add heat had kicked in).

It seems counter-intuitive, but would it help to open up some more rads? I've switched some off upstairs in rooms we don't use, but maybe this is having the opposite effect to intended?

Or maybe it's time to bite the bullet and get a pressure gauge fitted to the cold loop to see if that's an issue? There's a pressure relief valve on there, which I might be able to swap for a relief value and built in gauge.

lovesgshp

Good idea to reopen the rads, to see if that helps. From the sounds of things, they have not got bypass valves fitted, so you may be getting a flow restriction. How long since the mixer valve was fitted did you close some rads down? You need at least 70% of the system open.
Re the ground loop, then you would also need a filling point from the mains water system so that you could adjust the pressure if required.

beardymarrow

lovesgshp wrote: »

Good idea to reopen the rads, to see if that helps. From the sounds of things, they have not got bypass valves fitted, so you may be getting a flow restriction. How long since the mixer valve was fitted did you close some rads down? You need at least 70% of the system open.
Re the ground loop, then you would also need a filling point from the mains water system so that you could adjust the pressure if required.

Cheers. No, the rads don't have bypass valves fitted. It was a few days after that I closed them, but then I'd been messing with the flow rates to get the deltas right, and my return filter (external to the GSHP) was a bit sludgy, so not really tried it with all rads open since sorting those things.

Don't suppose you know what model pressure valve (or even make) you have do you? I can find loads that would fit but only suitable down to 5deg, and obviously the ground loop can easily go as low as -5.

lovesgshp

Mine is a Italian one, but you should be able to get one similar to this:
http://www.tecnogas.net/en/products/manometri-per-acqua-a-norme-ispesl-o-50
The one above operates to -20C

beardymarrow

lovesgshp wrote: »

Mine is a Italian one, but you should be able to get one similar to this:
http://www.tecnogas.net/en/products/manometri-per-acqua-a-norme-ispesl-o-50
The one above operates to -20C

Thanks. Bits bought to convert my pressure relief valve into a pressure relief valve with pressure gauge, and also a tee off for the filling loop. Will let you know once fitted. Of course I won't know if the system is low pressure now, as I'll have to relieve the pressure to fit it :-) From the manual I need to then pressurise back to 1-1.5Bar.

Correction to the previous message. I do have a bypass. I was being an idiot when I said I didn't. I thought you meant some sort of bypass on each radiator, not the main bypass. Wasn't thinking straight.

lovesgshp

Hi
You should be able to close some valves on the line to reduce the pressure drop. Probably the input line and one from the pump outlet. Close all that you can see while you make the change. Pressure to 1 bar max at the moment.
With the bypass valves, we normally think of these types for the rads. You may have a radiator that is operating as a similar system.
http://www.myson.co.uk/products/automatic_bypass_valves.asp

beardymarrow

lovesgshp wrote: »

Hi
You should be able to close some valves on the line to reduce the pressure drop. Probably the input line and one from the pump outlet. Close all that you can see while you make the change. Pressure to 1 bar max at the moment.
With the bypass valves, we normally think of these types for the rads. You may have a radiator that is operating as a similar system.
http://www.myson.co.uk/products/automatic_bypass_valves.asp

Will do. There's only a short length of pipe between the valve on the top of the GSHP and the 3 flow valves on the loop, so it'll be very minimal loss.

I don't have anything like that fitted. Just got the main bypass pipe across the top of the GSHP between CH in and CH out.

We do have one big radiator (in the hall near the temp sensor) which is full on, so I guess that's a bypass as well.

Doing an experiment this morning with putting a load of loft insulation around all the CH pipe work in addition to the climaflex to see if I'm losing heat within the boiler room.

Xander_Sim

Hi all,
Pretty cold week here!

I've just been doing a few checks and noticed one of the sensors (GT11) is way out - reading at over 100C, have any of you seen this before with a sensor and know how to remedy?
I'm not even sure where the GT11 is located..
It doesn't seem to have affected anything.

Cheers
Xander

beardymarrow

Xander_Sim wrote: »

Hi all,
Pretty cold week here!

I've just been doing a few checks and noticed one of the sensors (GT11) is way out - reading at over 100C, have any of you seen this before with a sensor and know how to remedy?
I'm not even sure where the GT11 is located..
It doesn't seem to have affected anything.

Cheers
Xander

Hi Xander,
GT11 is the output of the collector pipe. I would assume it's underneath the armaflex on the cold outlet (back right), but I could be wrong as it's a prefitted one. It's definitely within the GSHP itself, not external.

Are you getting an alarm for that sensor?

Over 100deg would suggest to me that it's shorted out as 0ohms would give that sort of figure for GT1. Doubt it's as simple as just buying a replacement sensor for a couple of quid (like you could with GT1) and fitting it yourself though :-(

lovesgshp

Hi Xander.

It is probably a sensor fault, I have only had it once on my unit. It is a quick job to replace, once you have a new one.
The sensor is located under the right hand panel of the pump, on the outlet line from the ground loop pump. There should be a thin lead going into the insulation/foil covering, (probably black). Sensor is only a few cms long, so easy to see.
The new sensor will come with the connection for the panel and it is just a case of changing over. Very easy.
HTH