Moisture Problem

[spades]

I’ve got a 30 ton process chiller full of water refer side. Open to suggestions to what would be the fastest way of removing the moisture after drilling holes in the low spots on the system blowing out with dry air and making some thing like a suction accumulator out of a refer tank with a core drier on the out let to keep majority of moisture out of the vacuum pump any suggestions would be appreciated.

Spades

[master mechanic]

Replace the chiller it will save in the long run. Your time and effort will be wasted tring to dry the system with vacuum pump, core driers and oil changes.

[scott123]

Yup....30 ton process chiller just isn't worth the effort. Just purchase a new one.

[enart9591]

Just finished dehydrating one circuit (250 tons) of a 500 ton RTAC (air-coooled screw chiller). I had quoted 120 hours and we used every one of them. Part of the agreement with the owner was that they would have their personel monitor the vacum pump and change the oil hourly, then every several hours, and then daily or as needed as evidenced by moisture in the vacum pump. We ended up using 20 large nitrogen tanks and 40 gallons of vacum pump oil. The process took over a month of time and multiple trips.

I would be happy to detail the process if you are interested.

[spades]

Thanks for the replys replacement is not an option it is going to be a time consuming project again thanks

Spades..

[no8no3]

I feel for you, Spades....But finding a 30 ton process chiller fast, is almost impossible too. I assume you will be changing the compressor, and leaking evap coil. This leaves a condenser coil, maybe a suction accumulator, txv, piping, and hot gas set up if so equipped. I have had a lot of success on these smaller chillers by taking the water affected parts out completely and placing these in a "powder coating" oven overnight at your local paint/body shop. These ovens run at 350 to 400 degrees and will completely dehydrate these parts. This is so much quicker than the other route. But whatever you decide, good luck!

[master mechanic]

IF YOU NEED THE CHILLER ON LINE QUICKLY I SUGGEST CALLING AGRECKO OR ANOTHER CHILLER RENTAL COMPANY INORDER TO TAKE THE PREASURE OFF OF YOUR COMPANY. CREATE A SALES PROPOSAL FOR A NEW CHILLER INCLUDING THE RENTAL FEES. YOUR CUSTOMER WILL BENIFIT IN THE LONG RUN AND YOU CAN SLEEP EASIER AT NIGHT.


WHEN IN DOUBT CHANGE IT OUT

[maxster]

remove the TXV assembly and soak it in refer oil and blow it out with nitro,isolate the compressor and pull that down to 250 microns with an oil change.install core dryers that can be replaced on the LL.remove the evap heads and blow out the tubes and any other lines and the leak wherever it was in there.

[master mechanic]

GENTLEMEN,

SOMETIMES YOU HAVE TO KNOW WHEN TO HOLD THEM, KNOW WHEN TO FOLD THEM, KNOW WHEN TO WALK AWAY, AND KNOW WHEN TO SELL.

[spades]

This is 2nd stage of a 75 ton system sorry failed to mention. I figure the freeze protection failed . funny thing is when I showed up on site the guy said I think it's low on freon then started the 2nd stage scrolls did not sound very good.he said he ran it a couple times this way. Higher ups are deciding on weather to replace or repair I know I can get it dry and it gets a new TXV Big ? what about the scrolls running on water. Ya gotta love this trade. allways some thing.

Spades

[chiller mekanik]

You need a cold trap for starters.
Some people use dry ice, I prefer liquid nitrogen.
The dry ice gets down to around -105*, you have to mix it with c20 degreaser(in the old days we used R11), to me its a pain & it will work, but it is second best.
The liquid nitrogen gets down around -320*, its much more effective.
The cold trap is a heat exchanger of sorts, you can make one or rent one.
You pipe it between the chiller & the vacuum pump.
Use a large pump & large lines.
Keep the dry ice or the liquid nitrogen level up & you avoid having to change the oil so much.
Every once in a while the cold trap/heat exchanger may freeze up or ice over, you will then have to stop & melt with a torch.
Stay with it until you reach -12* on the wet bulb indicator, do a stand test, if it holds, your good to go.
Break the vacuum with dry nitrogen, meg the motor, pull it down again, add your oil, turn on chilled water & condenser water pumps, charge with vapor until the sat temp is above freezing, then & only then charge with liquid.
I've used this procedure several times without ever having to take any part of the machine apart & I've had machines where the compressor was completely full of water.
What went wrong to allow the water in?
Freeze? Busted tube?
If you have a busted tube or tubes, you will have to plug them to proceed.
Even if you have to retube or replace the bundle, you need to get this thing dry ASAP.
As a precaution you probably should install a core holder with a bypass configuration & a dry eye so you can change the cores without shutting the machine down.
I know some of this may sound extreme, but, believe me its the only way I would even do one.

[Edited by chiller mekanik on 07-15-2006 at 11:53 PM]

[traverse tech]

Have lotsa fun if you don't change it out.

I had a 90 ton Trane RTUA. That took out both comp. when it filled with water.

Changed Evap, Compressors and drilled holes in very u bend in the cond. and blow nitro. through system. Then put the vac. pump on for a week. Used a Aborber vac. pump for the first three days then went to a reg. vac. pump from there on out. Once I finally got it dry it ran great but as stated above a whole lot of hours.

Cold Trap would be the best way in my opinion.
TT