geothermal nightmare - loop line sweating

bandit86

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I had a geoflex geothermal system installed at my dad's place, works great, except for the loop coolant pipes sweating. house is constant 22degC which is almost 72F, no issues there. House calls for a 3.5 ton unit but ended up with a 4.5 Ton because of some clerical errors.

I checked the in and out loop connections, both about 52deg F or 11C which means there is not a lot of load on the compressor, out side should get colder as it starts to work harder.

The loop pipes run 20 feet through the basement, then through an insulated cold storage room, then exit the house through the foundation. The cold storage room has all sides and ceiling insulated with r10 or so, designed to have the whole room ground temperature. (that part works)

the loop lines running through the cold room are sweating or condensing, whichever term you prefer, even though they are insulated. it is getting to the point where I noticed mold growing in the room.

This room is almost air tight, so once all the humidity in the room condensed and went down the drain, it should have been dry as wellm yet 2 months have gone by and there is still water dripping fromn the coolant lines. Not in the rest of the basemen though.

I'm at a loss, I have no idea where this much water could be coming from. there are no hidden connections, all pipes are insulated with a neopreme - wetsuit type insualtion that came with the unit and works in the rest of the basement, just not in the cold room. No leaks as system seems to hold pressure once initial leaks at manifold were eliminated.

There was no evidence of a wet basement before the project. Had one basement leak in the cold room during major downpour but that was taken care of.
 

mscher

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Re: geothermal nightmare - loop line sweating

What's the % humidity of the basement cold room now?
 

bandit86

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Re: geothermal nightmare - loop line sweating

there is water dripping off all the lines, yet the rest of the house is pretty dry. I don't have a way of measuring
 

roscoe

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Re: geothermal nightmare - loop line sweating

its condensation, can only be coming from one place, the air.

The rest of the house is irrelevant.
You say the cold room is almost air tight; sounds like the perfect conditions for mold growth.

Get a decent hygrometer, then a dehumidifier.

You either need to dry that room out, or add more insulation to those pipes.
 

dolluper

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Re: geothermal nightmare - loop line sweating

You say R10 is that the foam ins....the sheets you tack on the wall if so you need a vapour barrier also...they vent on the bottom
 

marlboro180

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Re: geothermal nightmare - loop line sweating

Sounds like condensation to me. Cold room is nearly airtight, so condensation cannot evaporate to the surrounding air. One could try a couple things:

Add a real pipe insulation jacket to the (pex, I presume?) lines. Neoprene can work, but I would use armor-flex and wrap it with the foam tape as well for a good seal, paying close attention to the butt joints. You have to keep the temp. down on the outside of the insulation to stop the condensation as well as keeping it airtight. I have done a double wrap of armor-flex with good success inside soffits that kept getting damaged from A/C lines.Overkill, but got the results I wanted.

Another option would be to build some sort of enclosure , like a soffit , around the lines and ventilate it to the larger room. Probably more work this way and you would need insulation of some sort in it, and probably a fan too, so I would start by insulating the heck out of the lines.

Glad to hear the geo-thermal is working well. Cool stuff! I did solar thermal on my place, looked into geo-thermal and am still considering it...
 

a70eliminator

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Re: geothermal nightmare - loop line sweating

An oversized unit doesn't get to run long enough to wring out the conditioned space of moisture, it satisfies the T-stat too soon, it sorta short cycles the compressor.
Not saying for sure it's your problem but thats why sizeing is so important.
 

j_martin

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Re: geothermal nightmare - loop line sweating

You need to get a little air exchange in that space for sure. If the moisture is condensation, you need insulation covered by a tight vapor barrier over the cold lines.

There's a 2 part mix and paint on foam for refrigeration that does it all pretty efficiently.

hope it helps
John
 

a70eliminator

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Re: geothermal nightmare - loop line sweating

You need to get a little air exchange in that space for sure. If the moisture is condensation, you need insulation covered by a tight vapor barrier over the cold lines.

There's a 2 part mix and paint on foam for refrigeration that does it all pretty efficiently.

hope it helps
John
agree 100% a little conditioned return air may be your answer.
 

marlboro180

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Re: geothermal nightmare - loop line sweating

You need to get a little air exchange in that space for sure. If the moisture is condensation, you need insulation covered by a tight vapor barrier over the cold lines.

There's a 2 part mix and paint on foam for refrigeration that does it all pretty efficiently.

hope it helps
John

Pex is not happy with that stuff from what I have read. But we do not know what kind of pipe it is yet....good suggestion though.
 

marlboro180

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Re: geothermal nightmare - loop line sweating

An oversized unit doesn't get to run long enough to wring out the conditioned space of moisture, it satisfies the T-stat too soon, it sorta short cycles the compressor.
Not saying for sure it's your problem but thats why sizeing is so important.

+1 ----- What, bigger is not better????
 

j_martin

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Re: geothermal nightmare - loop line sweating

+1 ----- What, bigger is not better????

Believe it or not, with air conditioning, if you're going to err, err on the small side.

If it's too big, it'll shut down before it has wrung the moisture out of the air in the conditioned space. Wet feels warm, and has other problems as we are seeing here.

If it's too small, it may not quite answer the thermostat during peak conditions, but it will wring the air out so dry it feels cool. Also, running 100% is the perfect size for efficiency. Power is wasted during start up and bleed down.

If you want an engineering view of this whole thing, get an enthalpy graph and instructions for how to use it. It'll open up a whole new understanding of heating, cooling, and how moisture affects it.

hope it helps
John
 

j_martin

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Re: geothermal nightmare - loop line sweating

Pex is not happy with that stuff from what I have read. But we do not know what kind of pipe it is yet....good suggestion though.


If that's true, then you'd need to use a zipper type insulation, or insulation and vapor barrier tape. You need both insulation and a vapor barrier outside that insulation.

hope it helps
John
 

marlboro180

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Re: geothermal nightmare - loop line sweating

Believe it or not, with air conditioning, if you're going to err, err on the small side.

If it's too big, it'll shut down before it has wrung the moisture out of the air in the conditioned space. Wet feels warm, and has other problems as we are seeing here.

If it's too small, it may not quite answer the thermostat during peak conditions, but it will wring the air out so dry it feels cool. Also, running 100% is the perfect size for efficiency. Power is wasted during start up and bleed down.

If you want an engineering view of this whole thing, get an enthalpy graph and instructions for how to use it. It'll open up a whole new understanding of heating, cooling, and how moisture affects it.

hope it helps
John

Sorry, I was being sarcastic. You are correct, err on the small side. Maybe this will help someone out.
 

jeeperman

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Re: geothermal nightmare - loop line sweating

In your first post you mention that the cold room is virtually air tight.
You also mention that there is a floor drain in there.
That is where the moisture is coming from. That drain is supplying a virtually constant supply of new moisture to replace whatever escapes the cold room. If it ever does, since it is virtually airtight.

It is the same as having an open bucket of water in that room.
 

bandit86

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Re: geothermal nightmare - loop line sweating

ok, the pipes are black plastic, came with the package. it is insulated with the neopreme sock looking insulation, and wrapped with some more sticky foam where the insualtion didnt reach, like around the manifold.

We had 2 other houses with the same cold room setups, all open to the ground, never had a problem, but this is the only one with a floor drain. I will try to block it and see if it helps. The insualtion is styrofoam, expanding foam in seams and corners.

I thought the neopreme insualtion also acted as vapor barrier. good idea to insualte it some more, willtry that armor-flex too.

the unit is a 2 stage unit, only ran low so far. runs for what seems like a long time.

In theory, all the condensation should have dripped off and room dried up already. since it is air tight and no more humid air can get in, it should have alowed the moisture to drip down the drain and that should have solved the problem.

tried looking up armourflex, cant find any info on what it is or where to get it
 

marlboro180

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Re: geothermal nightmare - loop line sweating

ok, the pipes are black plastic, came with the package. it is insulated with the neopreme sock looking insulation, and wrapped with some more sticky foam where the insualtion didnt reach, like around the manifold.

We had 2 other houses with the same cold room setups, all open to the ground, never had a problem, but this is the only one with a floor drain. I will try to block it and see if it helps. The insualtion is styrofoam, expanding foam in seams and corners.

I thought the neopreme insualtion also acted as vapor barrier. good idea to insualte it some more, willtry that armor-flex too.

the unit is a 2 stage unit, only ran low so far. runs for what seems like a long time.

In theory, all the condensation should have dripped off and room dried up already. since it is air tight and no more humid air can get in, it should have alowed the moisture to drip down the drain and that should have solved the problem.

tried looking up armourflex, cant find any info on what it is or where to get it

Neoprene is not a real good vapor barrier, more like a retarder. Never seen a perm rating for it though. I just know water runs right through my wetsuit...

Try these for armaflex, made by armarcell. Sorry, I misspelled it. It is a closed cell pipe insulation that works great. They make a tape for joints and elbows that works really well too.

http://www.thomasnet.com/nsearch.html?cov=ON&what=Insulation:+Pipe&heading=41050204&pg=3

http://www.armacell.com/

http://www.armacell.com/www/armacell/armacell.nsf/ansHTMLSeitenLookUp/USA-TI_Frame?OpenDocument

The floor drain- does it have a wet p-trap in it? Then there is a possibility of water evaporating from there.

Install a cheap-o humistat and thermostat to get an idea where the room is.

Think dew point- cold / warm is relative.....

BTW - is this a new build?----
What I am getting at here is that new builds typically have a ton of moisture in them , largely given off by the foundation and concrete floors. Moisture can be a problem for a while, and given this is in a house where geothermal has been installed, the place may well be built as tight as a drum to maximize the return on the spendy geothermal system.
 

bandit86

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Re: geothermal nightmare - loop line sweating

maybe I described it wrong, it is a rubbery foamy insulation made for pipes, i thought it was neopreme. says ruba-tex on it, 3/8 thickness. means nothing to me, felt like wetsuit material.

not a new building, 35 year old farm house, no city water, no water trap by the look of it either.
 

marlboro180

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Re: geothermal nightmare - loop line sweating

maybe I described it wrong, it is a rubbery foamy insulation made for pipes, i thought it was neopreme. says ruba-tex on it, 3/8 thickness. means nothing to me, felt like wetsuit material.

not a new building, 35 year old farm house, no city water, no water trap by the look of it either.

Start w/ insulating the lines .....
 

Jeepster04

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Re: geothermal nightmare - loop line sweating

Its not abnormal to need a dehumidifyer in a basement. We personally keep two running but it depends on the size. You will always have some moisture seeping through the walls from the ground.
 
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