Ground Source Heat Pumps

lstevensuk

Will give it another day just in case, but as you say not good. The previous owner mentioned something about 'cassettes' being in the ground and it wasn't a continuous pipe. I'm unable to find anything about these 'cassettes' on the web though. Is it possible for a DIY job to drain a loop for a leak test? Although at nearly £800 for the test might be better to get my spade out 

beardymarrow

lstevensuk said:

Will give it another day just in case, but as you say not good. The previous owner mentioned something about 'cassettes' being in the ground and it wasn't a continuous pipe. I'm unable to find anything about these 'cassettes' on the web though. Is it possible for a DIY job to drain a loop for a leak test? Although at nearly £800 for the test might be better to get my spade out 

I've no idea what they mean by "cassette" either :-) They are either slinkies or a vertical bore hole. Much more likely to be a slinky unless your back garden is very small. Slinkies would be approx 1m deep.
Yeah, if I was you, I'd get my spade out. Start at the manifold at both ends of the loop as there's more likely to be joints there.

I don't know how you'd drain the loop to be honest.You might need a GSHP company to pump it out as it clearly won't drain with gracity. Assuming it's glycol propylene it is safe (in fact it's put in most fizzy drinks and a lot of foods). If it's ethylene glycol it's toxic.

Patrol

In addition to slinkies and bore hole there was something that was a compact array, and you could connect several of these together. Sample image of the sort of thing:

just a random picture I found on internet images, source url was

http://www.anglianhome.co.uk/goodtobehome/wp-content/uploads/2014/10/04-Ground-Source-Heat-Pump-Collectors.jpg

beardymarrow

Patrol said:

In addition to slinkies and bore hole there was something that was a compact array, and you could connect several of these together. Sample image of the sort of thing:

just a random picture I found on internet images, source url was

http://www.anglianhome.co.uk/goodtobehome/wp-content/uploads/2014/10/04-Ground-Source-Heat-Pump-Collectors.jpg

Cool. You live and learn. Looks like plenty of joints and opportunity for leakage :-(

DeeWestern

How is the system performing on one loop? Could it be a job you can put off until the weather is nicer?

Patrol

beardymarrow said:
Cool. You live and learn. Looks like plenty of joints and opportunity for leakage :-(

Indeed. I can't remember what scenarios this sort of thing was intended for (my 2 guesses for a smaller land area than slinkies are either borehole unsuitable due to ground composition or cheaper than borehole?) but even two connections per panel wouldn't be great. Not sure if there are more than two - bit of a mare if that image has 2 + another 36 per panel.

(I only mentioned it as that was all I could think of without continuous pipe as mentioned above)

lstevensuk

Ok so not good news no more leaks overnight. @Patrol great find! The garden is pretty small so I think you are right. The owner did mention something about there being joins between the arrays and that there are 2 of them on each loop, so it might be this. The garden is very heavy clay soil so it could be likely some ground movement has knocked the joint.
Had the same thought about leaving it on just the one loop. How do I know if it's performing ok? Just compare the GT10/11 readings?

beardymarrow

lstevensuk said:

Ok so not good news no more leaks overnight. @Patrol great find! The garden is pretty small so I think you are right. The owner did mention something about there being joins between the arrays and that there are 2 of them on each loop, so it might be this. The garden is very heavy clay soil so it could be likely some ground movement has knocked the joint.
Had the same thought about leaving it on just the one loop. How do I know if it's performing ok? Just compare the GT10/11 readings?

Oh balls 😢. Yes, compare the gt10/11 readings and the gt6 temp. I'd be surprised if one loop was sufficient for the depths of winter, but if it runs fine now when it's not cold, you might as well. Just switch the other loop on when you need it. 

Patrol

Can you also see the total hours for ground loop and for additional heat (these are settings 7.1 and 7.3 on my IVT unit), or keep tabs on your electricity meter so you don't get caught unawares by a higher electricity bill.

I remember being told to use something like 30cm of sand around the slinkies when I laid mine to prevent air gaps, damage from stones, etc. If/when you do dig it up you might want to consider that when recovering it if there is no sign of anything other than clay.

lstevensuk

Something strange has happened! I thought I would switch everything back on for the week so I can monitor total hours etc. I've  checked everyday and I've not lost a single drop  This thing has been loosing it every week for months and suddenly after switching back off and on nothing!