external reservoir level dropping

[dvschillin]

I have recently started servicing a lot of rural residences and have been running into more and more geothermal units. most calls are the usual change filters, clean coils, bad controls, etc... but I have this one that has an external reservoir and is losing antifreeze gradually. The system is about 15 years old and when I first looked at it two years ago I could see where the level was when it was new which was several inches above where I found it. So I marked it and it has dropped about 1 inch each year i have been back.

So my questions are:

1) is this normal?
2) how do I know what solution to add to the system?
3) if the loops are leaking can this be fixed?

[pecmsg]

Glycol has a lot of expansion and contraction with temperature that may be what you’re seeing.
A refractometer is used to check the dilution level of the glycol. As far as what type take a sample and have it analyzed.

[IRBH]

With the reservoirs I've seen, an inch drop would be under a gallon.

That could easily be evaporation of the water portion of whatever heat exchange liquid is used.

If not, 15 to 40 gal should run it to the end of its' predicted lifespan.

[wahoo]

We still use methonal in our loops and homeowners top off with windshield washer fluid (blue stuff). Do you have any idea what most are using for anti-freeze?

[SkyHeating]

That little of a drop should be no problem, however if its a non pressurized system it may have been converted from pressurized to non because of a leak. Otherwise evaporation will easily explain that little of a drop.