Water where it should not be

[Emmett]

Hey guy's
Saturday I was lucky enough to find my cascade refrigeration system had water in the refer circuit
I have seen water in other older systems in the past and we always condemned the unit and replaced with new, however in this case we are dealing with a brand new system that has only been on-line for less then a month. The manufacturer will be here today, any recomendations on how to deal with this situation? the system in question is R-508B, has polyol ester oil and holds about 80 lbs (50 hp comp).

[NoNickName]

Cascade with water? What sort of freezing?

[Emmett]

Good question, the best I can figure is this. Several systems wen't down at 1 am on Hi stage Hi pressure, I assume we lost water flow. This unit has a desuperheater (water cooled), and a equalization valve, this valve allows Hi side gas to move to the low side of the system in the off cycle, I have observed liquid migrating out of the cascade condenser backwards in the off cycle. I believe that what may have occured is, the lack of water flow and liquid migration met and created the perfect storm so we froze the tubes in the desuperheater. (best guess) at this point, I will provide more info as it becomes available. What I am curious about is, what can they do to clean this system up? Obviously drain the water and oil, perhaps purge with nitrogen and pull multiple vacuums. any other ideas?

[Gingerair]

Hi Emmet

The amount of work required will depend on how much water has entered the system, what it's passed through & where it's ended up..

You need to check if there's any water in the oil & drier shells (if they're the replaceable type).

If you've been lucky & the plant went out on lp & not much entered the fridge side you may get away with a repair, vac out, new drier, oil & gas..

If you've been unlucky & the water has gone right through the system, contaminating the oil, then depending what type of compressor(s) you have, they may require a strip down, inspection & re-build.

The system will need to be dried out- Any low points of pipework can be drilled to drain any water that may have settled there, this will speed up the drying process. Any of these drain points & open ends then need to be plugged/blanked & the system pressure tested then put on vac. This next part may take a while, you will need a decent vac pump, plenty of vac pump oil, nitrogen & if possible an electric heat gun. Have the gas ballast open on your vac pump & change the oil whenever it turns milky, regularly breaking the vac with nitro then re-pulling a vac will help this process along.

When an acceptable vacuum is achieved & you are confident that all the water has been removed, carry out any system repairs & if one is not already fitted a replaceable core drier shell & isolation valves. You will have to ascertain if suction filter(s), new sight glass, etc are also required.. Re-fit compressor(s), new oil charge where required & re-commission.

Further oil & filter/drier core changes may be required as any debris/contaminants are washed through & settle out. You could now have an oil & gas analysis carried out for a reference of the system condition at this point.

There is also the option of having the system 'flushed through' with a cleaning agent, but in my own experience this causes more problems than it solves..

I presume you already know a lot of the info above, just wanted to sound methodical

Ranga

[Magoo]

free water in any refrigeration circuit is not good, whether cascade or single stage. Water freezes and blokes things, added feature is oil contamination and acid generation. you have a serious system problem.
magoo

[NoNickName]

Ok, so probably the condenser behaved like a flooded evaporator. It probably empties when the liquid solenoid opens, and freezes the condensing water.
Is there a design flaw maybe?

[Emmett]

There is also the option of having the system 'flushed through' with a cleaning agent, but in my own experience this causes more problems than it solves..
Thanks Ranga I was curious about this option, and I appreciate the information you've provided. reading your message was like you were reading my mind.
NoNickName and others I would like to post a diagram of the system it would make the discussion go easier however I do not know how to do that at this time, if someone can enlighten me I would gladly post it so others could mentally disect the system and help me determine where things wen't wrong. And yes I suspect a flawed design approach, I have had nothing but trouble with this equipment since the manufacturer shiped it to our site, it took close to a year to install and commission, was meant to be a two month ordeal.

[Gingerair]

Hi Emmett

Sounds like this one has got a bit of way to go yet, would be interested if you can post any diagrams/pictures..

[Emmett]

I am unable to post the diagram as the file size is to large, (unless someone can explain a way around this)The manufacturers technician spent several days removong water, has identified which of the two de-superheaters has sprung a leak and replaced it with a new one, he left a standing nitrogen charge on the unit and then left town for an emergency call (so much for my emergency) say's he will be back tue or wed, I will update you as information comes in.

[Gingerair]

I'm not sure how to do it Emmett, maybe one of the moderators can help ??

...I'm still waiting for my green & blue cap, gloves & overalls to arrive since i got past 15 posts...

Hope the cause of failure was manufacture & not a design problem..

[Emmett]

I'd be happy with an RE patch
I dont know why but for several weeks I have been running slow on this site, my computer works fine on other sites so I had suspected something wrong here, I am going to post on the need help forum and see what becomes of it. I would really like for you guys to see what I am dealing with.

[NoNickName]

Works greatly and quickly for me.

[Emmett]

Not much new to report, Technician from Manufacturer identified which De-superheater was leaking cut it out drained water and ran dry nitrogen then he replace de-superheater with new then he pulled vac and purged with nitrogen. I had expected to see him on monday morning when he did not show I called and he was back home, said his boss would e-mail me with detailed plan, havent heard back from them yet.