Geothermal Ground Loop - Leak

0lordy

Hi there,

I have an Alpha Innotec heatpump with a horizontal ground loop for the past 3.5 years, no issues apart from instances of a "Low Pressure" error.

Happened 5 or 6 times in the last 6 months, didn't happen at all in the previous 3 years.

It's easy to resolve, by topping up the ground loop using a hose to an inlet tap in the heat pump itself, but the frequency is a concern, especilly since it will probably become more rather than less frequent.

Am getting some level of support from the supplier, but would like to understand if this is a common issue, and what can be done to fix it.

So, the question is: assuming it's a leak in the ground loop, has anyone successfully traced and fixed such a leak? Looks like a lot of digging might be involved!

Thanks

Condenser

edt

Condenser

It could be its not a ground loop and leak its a refrigerant leak. Supplier should know that in 2 seconds. Or else you have a major leak outside that prevents any circulation. These are 2 of the only 3 reasons for a LP error. If its the first you'll need a refrigeration engineer to remove the remaining refrigerant and leak test the system with nitrogen. Make sure their F-gas certified or you'll be breaking the law.

0lordy

Condenser wrote: »

It could be its not a ground loop and leak its a refrigerant leak. Supplier should know that in 2 seconds. Or else you have a major leak outside that prevents any circulation. These are 2 of the only 3 reasons for a LP error. If its the first you'll need a refrigeration engineer to remove the remaining refrigerant and leak test the system with nitrogen. Make sure their F-gas certified or you'll be breaking the law.

Thanks for your response - Of course I might be wrong, but I'm pretty sure it's a ground loop leak - resolved by refilling the ground loop via the inlet tap with water (located in centre of heat pump, when front is removed), as advised by the supplier. I don't think it's a major leak outside, as it works fine for a period of time before the pressure drops too low. Ironically, a major leak would be better, as it would be easier to find.

By the way, the pressure is shown on the pressure gauge on top of the heat pump - normally should be at 1.5 bar, but drops eventually to below .5, then the LP error is displayed.

Hope this clarifies things a bit better, and supports the ground loop leak theory!

Thanks

Condenser

0lordy wrote: »

Thanks for your response - Of course I might be wrong, but I'm pretty sure it's a ground loop leak - resolved by refilling the ground loop via the inlet tap with water (located in centre of heat pump, when front is removed), as advised by the supplier. I don't think it's a major leak outside, as it works fine for a period of time before the pressure drops too low. Ironically, a major leak would be better, as it would be easier to find.

By the way, the pressure is shown on the pressure gauge on top of the heat pump - normally should be at 1.5 bar, but drops eventually to below .5, then the LP error is displayed.

Hope this clarifies things a bit better, and supports the ground loop leak theory!

Thanks

You're losing pressure on the ground loop side but an LP fault is a refrigerant problem. The LP fault may well be caused by the low pressure on the collector side, which if low enough would affect the ability of the antifreeze to flow. This in turn would reduce the amount of energy the heat pump would receive, which would lead to the gas temp and pressure dropping, hence the LP fault. Although I would wonder why this is happening with 0.5 bar still in the collector. It should keep running.

First thing to do is check all joints behind the heat pump, then check all joints in the manhole outside. If these are ok you'll need to seperate each loop on the collector manifold and pressure test. If you find it there you may have to decide whether to dig and try and find it (only recommended if its a loop at the edge of the collector or replace the loop by moving to a different area.

Also don't keep pumping water into the collector loop. You're reducing the glycol content and eventually that LP fault will result in a burst heat exchanger.

0lordy

Hi Condenser,

Thanks a million for your time and advice.

Condenser wrote: »

You're losing pressure on the ground loop side but an LP fault is a refrigerant problem. The LP fault may well be caused by the low pressure on the collector side, which if low enough would affect the ability of the antifreeze to flow. This in turn would reduce the amount of energy the heat pump would receive, which would lead to the gas temp and pressure dropping, hence the LP fault. Although I would wonder why this is happening with 0.5 bar still in the collector. It should keep running.

Hmmm, you might be right, it may go below .5 before the error kicks in

Condenser wrote: »

First thing to do is check all joints behind the heat pump, then check all joints in the manhole outside. If these are ok you'll need to seperate each loop on the collector manifold and pressure test. If you find it there you may have to decide whether to dig and try and find it (only recommended if its a loop at the edge of the collector or replace the loop by moving to a different area.

All joints inside are fine, I'll check outside tomorrow when I'm back in the house.

Condenser wrote: »

Also don't keep pumping water into the collector loop. You're reducing the glycol content and eventually that LP fault will result in a burst heat exchanger.

Thanks for that advice.

0lordy

Yep, checked the joints in the manhole, and although I couldn't get down into it, some of the joints seems wet. The ground below was wet too, but that could be ground water seeping up.

Will get down into it to get a closer look, but that'll be early next week.

Condenser

0lordy wrote: »

Yep, checked the joints in the manhole, and although I couldn't get down into it, some of the joints seems wet. The ground below was wet too, but that could be ground water seeping up.

Will get down into it to get a closer look, but that'll be early next week.

Dry them with a towel and then wrap some tissue or kitchen roll around them. You'll know if they're dripping in 5 mins. Make sure the machine is off or you could create condensation on them.

0lordy

Condenser wrote: »

Dry them with a towel and then wrap some tissue or kitchen roll around them. You'll know if they're dripping in 5 mins. Make sure the machine is off or you could create condensation on them.

Nice one, there did indeed seem to be a leak at the bottom, where the main return pipe to the house joins the manifold. It doesn't appear to be leaking that much, not enough to explain the speed of the pressure drop - got the LP error today again, just one week after the last time. The pressure went from 1.5 to .2 bar.

In any case, I'll get it checked out and fixed, and take if from there, and report back.

Thanks for your help.

0lordy

Been a while, but eventually got it sorted - located a leak which was underground, beside the manhole. It was at the coupling joint on the main return pipe. A digger was required, so messy enough piece of work, but good to find the source.

Hopefully that's the end of the problem...

Outkast_IRE

quick question wouldnt the constant topping up with fresh water of diluted the antifreeze ? Have you topped it up with antifreeze just giving it a mention in case its another cold winter.

0lordy

Outkast_IRE wrote: »

quick question wouldnt the constant topping up with fresh water of diluted the antifreeze ? Have you topped it up with antifreeze just giving it a mention in case its another cold winter.

Yes, had a chat with the supplier about this last week, it will need an anti-freeze top-up alright, before the cold weather kicks in. Like now I suppose...

Thanks for the heads-up anyway.

susandnig

Same problem - definite leak in one of the collector loops. Has anyone any advice re detection of leak? With 600m of pipe 1M deep in a landscaped garden I dont want a " big dig" Surely some liquid or gas can be pumped through the system which would pinpoint the location of the leak?

0lordy

susandnig wrote: »

Same problem - definite leak in one of the collector loops. Has anyone any advice re detection of leak? With 600m of pipe 1M deep in a landscaped garden I dont want a " big dig" Surely some liquid or gas can be pumped through the system which would pinpoint the location of the leak?

Based on my (limited) experience - the first step is to check the joints, as in all likelihood this is where a leak will be. My leak was about 50cm away from the manifold outside, roughly 1.5m underground - at a connector joint to the main pipe between the manifold and the house. A digger was required to get at it.

If it's in the ground loops themselves, it might be an option to isolate them one at a time (if they can be shut off) and test for a drop in pressure. Otherwise you may have to do a pressure test on each to test. A plumber job.

If you find that one loop has a leak, then the solution might be to lay another one instead of digging the faulty one up.

Either way, you need to ensure that the heat pump is not regularly faulting for low pressure, as this can cause problems in the heat pump - basically causing the water to freeze and then crack the refrigerant piping, requiring a replacements & gas refill.

That's all I know, the caveat being I'm no expert, and will defer to the more knowledgeable folk on here.

Feel free to PM me if you want any more info.

susandnig

leak is def outside - pressure tested by plumber - also checked joints but no joy so waiting to isolate 2 collectors to see which is leaking ( hopefully not both) then I'm thinking of using a leak detector company using sonar.
Its a long shot but I hate the thought of digging - another angle is pump a leak sealing fluid in for €500 approx and its not guaranteed to work.
Thanks for the advice olordy - not very happy with solutions coming from the installation company - cant be the first to leak yet feel like I'm re-inventing the wheel for solutions.