Cleaning the A/C water cooling system / How to

[rustybucket]

Just to add, my go-to cooling system cleaning/circulation pump is a 110v harbor freight sump pump, whatever the smallest they had was. I plug into a surge protector so I have an easy on/off switch.

Also, instead of barnacle buster or muratic acid I prefer D Scale, it's available at most HVAC or refrigeration companies, is used to de scale industrial heat exchangers and is safe on the metals.

For double duty, after cleaned the sump pump lives in a bucket on the boat and could double as an additional crash pump if needed. Standard water hose bib threads on top of it so will hook to any garden hose.

[racclarkson@gmail.com]

Just to add, my go-to cooling system cleaning/circulation pump is a 110v harbor freight sump pump, whatever the smallest they had was. I plug into a surge protector so I have an easy on/off switch.

Also, instead of barnacle buster or muratic acid I prefer D Scale, it's available at most HVAC or refrigeration companies, is used to de scale industrial heat exchangers and is safe on the metals.

For double duty, after cleaned the sump pump lives in a bucket on the boat and could double as an additional crash pump if needed. Standard water hose bib threads on top of it so will hook to any garden hose.

As an alternative, Kleen Strip Concrete & Metal Prep is the same stuff at about $18/gal at Home Depot. I use a 17:3 ratio (17 quarts of water + 3 quarts of solution which makes a handy 5 gallons). Everyone keeps their concentrations proprietary, but going down the middle gives an estimated 10-12% diluted solution which is, more or less, the same as Barnacle Buster at a quarter the cost. I always keep a jug onboard to paint on any rust that pops up. If you use it in your engines, don't forget to first take out the zincs.

IMG_9589.jpg
Here's one of my HE's after a recirculating cleaning.

But, I gotta say that I'm pretty hesitant to use it on my HVAC system these days. After replacing a compressor on my 36K BTU sixteen months back, I lost its cooling loop a few months later. Fortunately, I addressed it while there was still some positive pressure in the system. The system tested good, so a new cooling loop has been in place for a year now. Maybe no link, but those systems are nowhere as robust as the engines and associated coolers. What I do do is keep the HVAC strainer basket full of bromine tabs. A look in the cooling loop shows clean, if not shiny, pipes. So, maybe it'd be a good idea to take a look-see to make sure the system needs the acid treatment. If nothing else, a check on the water discharge tells a lot when all else is running fine.

X2 on the bucket pump. It's always ready and good insurance.

[oscarvan]

So out of curiosity.... how should one ought to dispose of these chemicals afterwards?

[johnjen50]

Robert, about how long do you circulate it for? Thanks, thats cleaner than I got mine with vinegar.

[SKYCHENEY]

So out of curiosity.... how should one ought to dispose of these chemicals afterwards?

Dilution is the solution to pollution.

[Westfield 11]

You cannot get more diluted than mixing it with the ocean. Does that mean just dumping it overboard? If one is using phosphoric acid, I believe the phosphorus is a known contributor to algae blooms, is this an issue?
The last time I performed this cleaning I disposed of the residue in the sink in the boatyard assuming that the water treatment plant could process it and that that was a better alternative to overboard.

[racclarkson@gmail.com]

You cannot get more diluted than mixing it with the ocean. Does that mean just dumping it overboard? If one is using phosphoric acid, I believe the phosphorus is a known contributor to algae blooms, is this an issue?
The last time I performed this cleaning I disposed of the residue in the sink in the boatyard assuming that the water treatment plant could process it and that that was a better alternative to overboard.

Why would anyone with Detroits worry about algae? Seriously, the BB video claims, or used to, that it was safe to dump overboard. I think they're in Ft. Lauderdale. No algae blooms down there, right?

[racclarkson@gmail.com]

Robert, about how long do you circulate it for? Thanks, thats cleaner than I got mine with vinegar.

John, from 45-90 mins. When the discharge starts looking blueish again with no foam is what I look for. Then crank the motors to clear out the solution, or if you're me...

IMG_0188.jpg

... hook up a garden hose and flush for 10 minutes. In fact, I don't have to descale anywhere near as often now because I always freshwater flush the motors after running. But when I do descale, the hookup is a cinch.

[rustybucket]

For the hvac systems I always flush with a baking soda solution after the acid and fresh water. I have 3 buckets when flushing, one for acid, one just plain water and one with a couple pounds baking soda. Flush with acid for 5 or so mins, water with a couple mins, then baking soda for a couple mins. I use the same pump in all 3.

[johnjen50]

Thanks Robert. Yes, I remember when you first posted that little piece of plumbing genius. Love that. That's going into my system this winter.