Water in system...

Rufusz · 17-07-2011, 01:37 PM

Hi guys,
I had a call a weeks ago regarding a broken water chiller (80kW Ciat, 2x40kW Danfoss Performer scroll compressors, R407c), and it turned out that the evaporator broke last winter due to ice damage, as the maintenance guys forgot to drain the water from it...(and they were too greedy to put some glycol in the system)

The R407c charge escaped through the water side's air bleed valves and the water flooded the compressors and the condenser. A couple of months ago they wanted to start the system, but the LP switch was tripped, so one clever guy overrode it...after a couple of forced starts they managed to kill the compressors.

So I ordered 2 new compressors and an evaporator and started to dry the flooded part of the system with Nitrogen and deep vacuum. To cut the long story short, I made a stupid mistake and some water was still present in the system when I charged it with refrigerant and started the unit. After about 2 hours operation both of the compressors stopped and failed to start again.
I reclaimed the refrigerant through a drier filter and found some water in the suction line...I guess it is also present in the compressors. I have no idea how it got through the new drier filter.
An other thing I don't understand is according to 2 different acid test, the compressor oil has no acid in it, despite of the water problem...

On Friday I started to dry the system again, but have serious doubts about the compressors if they will start again...

**nike123** · 18-07-2011, 01:49 AM

How do you knew that you have developed deep vacuum without using micron meter?
If you have used micron meter and blank off test, it will be showing you that you still have moisture.

Compressors will probably start again when you dehydrate system, if they are not mechanically damaged, but you need to install filter driers with replaceable cores to get rid of moisture trapped in oil by repeatedly changing cores until you get rid of all moisture from oil, and formed acid.

**mikeref** · 18-07-2011, 03:31 AM

Also, going to watch carefully the colour of the oil. I had serious problems some years ago with water in system and it took forever to clean out

. Lots of vac pump oil changes, lots of OFN, too many drier core replacements and oil changes. Sounds like your compressors had run dry of oil due to water infiltration, causing them to lock up.. Mike.

**HVACRsaurus** · 18-07-2011, 04:44 AM

I would expect under conditions you described that acids would not have had sufficient time to form. I'd expect acids to form only after extended operation. Suggest doing oil change as well - if possible..

**Tesla** · 18-07-2011, 07:42 AM

To save a little time you could weld in a bypass arrangement for changing the driers. Install a suction line core filter drier. It could take several months to completely clean the system. For the evacuation you need to vac well below 1000 microns then perform a vacuum hold test over 12 hours which should not go above 1000 microns. If you don't get that redo breaking vacuum with nitro and of course leaktest. The new compressors are already damaged and may not last if they even start again. Change oil at intervals of 25 hours then 50 hour running. You must monitor oil levels and try to give full load conditions as the oil is likely to log in cooler from running at lo loads. After all looks good from oil acid tests then you must run compressors for 100 hours, take a new oil sample and send to a lab for testing. Also check all controls and safeties along with water flow rates.

**Fri3Oil System** · 18-07-2011, 08:08 AM

Originally Posted by Tesla

It could take several months to completely clean the system.

Sth that can be done in one operation should no last several months, but several hours, maybe a few days in case the installation is very big.... but several months...
You can pull a deep vacuum, but, water remains below the oil, and it's just very difficult to evaporate it, even with the deepest vacuum. Using the proper method, it's not difficult to extract the oil, as well as water.After this process, you pull a vacuum to eliminate the moisture traces.

One day, you will believe me

Regards,

Nando.

**Tesla** · 18-07-2011, 12:08 PM

OK Fri3Oil
Please enlighten us with a procedure for a process in this case for removing all the contaminants from the system - I am still young and willing to learn from the more experienced. The reason I said it could take several months is I had a few systems with similar issues where there was not enough load to run the chillers to get up the running hours for drier and oil changes to remove not only the moisture but sludge and other contaminants - burn out. I know in the summer it might only take a week with a full load 24/7.

Rufusz · 18-07-2011, 02:21 PM

Thanks for the advice guys. I used a micron meter but I only measured the vacuum level for about 2 hours and since it was not rising I assumed it will be free of moisture...WRONG

So far I used more than 10m3 of OFN and a few liters of vac pump oil... This Afternoon I will add some more OFN then a 24h deep vacuum test. If everything works out it will be running by the deadline...

**mikeref** · 18-07-2011, 11:22 PM

Originally Posted by Fri3Oil System

Sth that can be done in one operation should no last several months, but several hours, maybe a few days in case the installation is very big.... but several months...
You can pull a deep vacuum, but, water remains below the oil, and it's just very difficult to evaporate it, even with the deepest vacuum. Using the proper method, it's not difficult to extract the oil, as well as water.After this process, you pull a vacuum to eliminate the moisture traces.

One day, you will believe me

Regards,

Nando.

If you were to post video on utube as to your method, it would help us "believe"

. My guess is you would circulate refrigerant throughout system via some external pump that also cleans out contaminants before re-introducing the refrigerant in a continuous loop. Yes?

.

**Fri3Oil System** · 19-07-2011, 09:03 AM

Hi!

I am younger than you, and as you know, I am not an engineer, but my father, who invented our system, started working almost 40yrs ago, and he is indeed a wellknown refrigeration engineer.

Coming to your question, cleaning water is the most difficult case when using our technology, simply because it is a longer process and water just creates problems. (ice blocks, i.e.). It's a little difficult to explain without anymore knowledge about it, and would mean a huge post... but we can try. I added anyway the instructions from our DVD manual.

Based on the attached schematic, we will use 2 external recipients, one is what we call the permanent REA (that keeps all the contaminants coming from the circuit: acids, oils, etc), the other one is the intermediate REA. This one will act as a by-pass in order to retain the major part of water from the installation.

To begin, we will inject with liquid refrigerant the plant, and wait for some minutes until liquids are "decanted" by their density: above oils+acids mix, then water, then refrigerant.
In this moment, we open the lines to the cleaning machine through the intermediate REA, having refrigerant with oils coming from the circuit. When water starts to exit, we will use the REA to retain the water, and avoid it enter our system, by opening the REA connections. Anyway, is compulsory to do a proper training to fully understand the cleaning process.

This operation will leave the system free of water. At the end of the cleaning process, the installation will be totally dry of oils and acids, and will only contain some moisture traces. Then it's the moment to deep vac it and break the vacuum with N2 until we are out of moisture.

And yes, the refrigerant is recirculated to extract all the contaminants, and after the process, it will be reused with warranty, as it is clean.

Carrier, Daikin, Trane, Johnson Controls, and many other companies have been using this method to get rid of water for some years now.

We have a video that we use for trainings, not a real case, but some cartoons. Recording a whole operation that can take one day, is not very good to upload it to Youtube. And, if you cut the video, many people would think the video has been manipulated.

I think I already told here about a client who wanted to check that our system really removes water, and his great idea was to hire a crane, and use it to sink a chiller in a swimming pool. They bought 3 systems after next day.

To end with, I never meant to advertise my system, but this is the only way to eliminate water from a system, and for you, the only way to give a "quiet" warranty to your clients.

I will be happy to answer your questions.

Regards,

Nando.