View Full Version : Cleaning a glycol line and jackets?

08-15-2013, 01:02 PM
The glycol system in my brewpub is at least 10 years old. I believe the piping is 18 years old (the age of the company). In general, it's been pretty well maintained. There is one reservoir and three loops; 1 chiller coil and two tank. Each loop is individually pumped.

Recently, we noticed a rise in the glycol reservoir temperature and slightly longer crash times. Thinking it might be worn out glycol (18 months old) we scheduled a drain and change. During that glycol change (a week ago) I noticed a pretty slow return flow from the cooling coil. It seemed like a physical blockage, so we hooked up a hose and backflushed it. We noticed some white, sand-like particles coming out. They looked like CaCO3 chunks and dissolved in phosphoric acid. It took an acid flush of the coil to clear the deposits.

So, I'm assuming random distribution could mean a similar buildup in the tank lines and jackets. At least one tank may be showing symptoms, since it's very slow to crash (over 48 hours with 30F glycol). I don't really want to do an acid rinse on that whole system because of cost, old plastic and unknown parts and plain 'ol ignorance of what might happen.

Has anybody else had to do this? One idea I had was to recirculate with RO or distilled water, thinking the minerals might dissolve into that.

dick murton
08-15-2013, 01:45 PM
Unfortunately if you have washed calcium carbonate deposits (if that is what they are) with phophoric acid, you will have converted much, possiby a of it into highly insoluble calcium phosphate. In the mashing process, clcium chloride / suphate is added to precipitate the phosphates in the malt, and reduce the pH. If it is calcium carbonate left, then the best material is to use nitric acid to create highly soluble calcium nitrate. I'm not sure if nitric acid will dissolve calcium phosphate but it has to be worth a try. Don't use hydrochloric as this is likely to wreck any stainless steel.

If it doesn't wash off with nitric, then I sugest you contact you chmical supplier. I suspect you may have to use a solution of EDTA or other similar material, which they will be in the best position to advise from their range of materials.

Warm, say 35 deg C will normally work better than cold. I don't suggest using hot, as it is may react a bit too vigorously - again the chemical supplier can advise.

In future make sure the glycol is made up with demineralised water - RO or distilled rather than softened.

08-17-2013, 01:08 PM
Thanks Dick!

I ran this past a chemist friend and he came back with advice that pretty much mirrors yours. I'll be making a chem order on Monday and will get their advice, too.