De-ionized water (Continued)

JoeC

I've without a doubt appreciated the responses to my earlier question, and we're all learning here.....So, what I'm asking now is, in regards to hydronic systems running glycol, can I add "softend water" from my water softener system that uses salt, or, may I use the water I run from my Reverse Osmosis system into the boiler feed? My larger steam boilers all operate off a 'salt' softener that feeds those systems, will that type of softened water destroy my glycol hydronic systems, is there some ion science class I'm not following here? I'm listening!

hr

For the hydronic question

I would use RO not softened water. I'm not a steam guy, Maybe Glenn or Noel could answer this best.

From the Dow Engineering Guide

"Dow fluids should only be diluted with demineralized water that has been distilled, deionized, or passed through a reverse osmosis process to remove potentially troublesome minerals and salts." Personally I don't fell ac condensate water is what they have in mind. I don't see how the minerals are removed by passing over a cold coil?

"Good quality water should contain only minute traces of calicum less than 50ppm, magnesium less than 50ppm, chloride less than 25ppm, and sulfate less than 25ppm. Total hardness less than 100ppm."

I'm not sure many heating contractors have the equipment to test for all this? But your chemicial supplier should, that's their business

Check with the manufacture of the products you are planning to use, however. I'd imagine all glycol manufactures will use this or a similar spec.

Plenty of installers use plain tap water, but you really need to keep an eye on that fluid on a yearly basis. When glycol goes bad, ugly things, and often expensive things, go wrong quickly. Not something you can spot from the outside, generally. Could be an major problem on a large commercial job.

My point is why risk it? Use the RO water or buy preblended glycol from the manufacture. To spend 8, 9, 10 bucks for a gallon of glycol then ruin it with bad dilution water doesn't make good sense when the correct method is so simple.

hot rod

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bob_25

Hot Rod

The water in the air is in the form of steam at low pressure. When you condense it out of the air by contact with a surface below the dew point you get distilled water. IMO it would work well with glycol. I am not any kind of authority on water. I have worked with DI water we measured the purity in megohms, if I remember 18meghoms is about the best you can get. This water is very aggresive we had to use polypropelene pipe to maintain purity, 316 ss wasn't good enough. I found out the hard way that electronic low water cut offs won't work with pure water. I have seen the result when glycol goes bad but I never thought it was caused by water I usually saw it in boilers that have very small surface area and thus high local temps. This is just some of my personal experiance for what it's worth. bob

Dave Bush

Re: Hot Rod

On an ac evaporator coil, water doesn't actually pass over the cold surface.

Condensation forms on the coil, from the humidity in the air. (Humidity travels to the coldest surface it can.) It is, in fact, true distilled water.

As a side note, several years ago, we installed a 10 ton Dectron Dry-O-Tron indoor swimming pool heating-cooling-dehumidifying unit, at a resort that has 4 regulation golf courses, that use electric carts. The condensate from this unit drains to a five gallon pail, containing a submersible pump, which sends it to a pair of 55 gallon drums to be stored for use in the golf cart batteries. I wish I could take credit for that idea, but I can't. It's an excellent use of that "waste" condensate.

Bear in mind, this is not a standard air conditioner/heat pump, but an actual climate control system for the indoor pool itself (Pool water is heated in this unit) and the indoor pool room. LOTS of condensate is produced.

It would be great, if someone had a large enough AC unit like this one, to catch the condesate to use for boiler makeup water.

jerry scharf_2

contamination

Dave,

You are correct that the water as it condenses shuld be very clean. It's what happens between that second and when you collect it that is the problem. Condensing water is a magnet for anything that's in the air. That's why they tell you not to eat hail stones, the whole thing about acid rain and the like. Then you have organics that decide to grow in the collection area, certainly not clean.

I would certinaly run whatever you get out of the drip pan through a RO filter before using it in a boiler!

jerry

PJO_5

Another thought or two...

Be careful of the pH factor with this water...it has little or no buffer and tends to be acidic.

Also, 316LSS piping is used very often on high-purity systems. I just completed work on a 18 megaohm system (you are correct; 18.3 or so is the theoretical highest) for pharmaceutical spray coating, and is constant circulation of 80C temperature through this piping. I don't think the poly pipe would have held up! :-)

Yes, the water off these coils would be nearly pure, as someone said it's the container that's the issue...whether it's pipe, bucket or otherwise.

Take Care, PJO