We have a Climatemaster 5 ton Tranquility 27 system (copper heat exchanger)
installed last year.  It has performed well, with just a minor problem that was
quickly fixed.

There is one other issue that has not been resolved yet, relating to the
fluid in the closed loop (vertical).

The loop contains a mix of propylene glycol and water.
Initially I was concerned that the pH would be too low,
as our domestic water has a pH of 5.85
We have a neutralizer to raise the pH for domestic use,
but the water for the loop was taken from before the neutralizer.

The loop fluid was then tested, and the pH was 9.0
This was measured after system was in use for a while.

Climatemaster document shows acceptable range for closed system
to be pH from 6.0 to 8.5

Is the fluid in the loop okay or does it need to be adjusted?
Is there a potential corrosion problem, or do any corrosion inhibitors
in the glycol make it such that the high pH is not a problem?

We were surprised to see the pH raised that much by the glycol.
Is that normal?

The driller only installed the loops and fluid, not the Climatemaster etc.
and is looking into this, but he has not been able to get an answer
from Climatemaster about this. The installer of the Climatemaster has
not commented.

I appreciate your help, and have learned much from other reading on the forum.

Anytime you are dealing with metal piping systems the ph should be as close to 7 as possible. If the solution is too acidic or high in alkaliinity there will be corrosion to any metal exposed to the fluid. Water treatment is required.Dow Chemical and Calgon would be a good place to start for info.

I would much rather deal with an alkiline than an acid. That being said the diff between 8.5 and 9 once you are that far north on the scale is miniscule. I would call climate master corporate and talk to their tek guys before you pull the trigger on any adjustments. Are your loops pressurised, or non pressure? If they are non pressure type adjustments will be easy. If it is pressure, perhaps you can get it changed to non pressure and then you can test and adjust to your hearts content.
hope this helps.
Eric

I'd say it's pretty hard to get pH 9 to corrode copper, but it is possible:

Pitting corrosion occurred only in low alkalinity (dissolved inorganic carbon) and high pH (9) water in the presence of chloride.

Thanks for the responses so far.

Does anyone have a good contact at Climatemaster to call?
The Driller has been trying to get answer from them, but has gotten no response yet.

I would second, or third (whichever it is now...) the idea that the pH of 9 will be far less likely to corrode copper. If anything, it may cause build up to accumulate at restrictions.