Daikin EWLD235J-SS (McQuay Compact line) chiller problem
I'm registered here for a long time ago, but this is my first post here.
Have a problem with condenserless Daikin chiller EWLD235J-SS (Daikin branded McQuay Compact line chiller), single circuit, with Frame 3200 compressor.
Air cooled remote condenser, ~15 meter liquid line, no receiver, plate heatexchanger evaporator, Danfoss EXV. The chiller is new, have been installed about one month ago.
Before this unit there was another Daikin unit with freezed evaporator and broken compressor.
Condenser remain the same, some kind of cleaning of tubes have been made by installer.
There are two problems with this chiller.
First one - is nonlinear increasing of compressor capacity.
When controller start to increase the capacity of compressor, current consumption increase very slowly. Its change from 52 to 70 Amps during capacity from 25 to 97%, and sharply increases up to 102A at 100%. After it chiller goes to High Pressure alarm or Low pressure alarm.
If I trying to increase Load Up Pulse Length from 0.3 s to 0.4 or 0.5 s, compressor increase its capacity more linear, but at some moment during loading up, low pressure is going down and unit is going in LP alarm once again.
Looks like expansion valve does not work correctly. There is a sight glass on EXV body, but it installed to close to compressor so I cant see anything on it.
Second problem - is a strange noise from compressor. When this sound is appear, low pressure is dropped down quickly and unit goes in to Low Pressure Alarm.
Here is the video from site:
Chiller start from 01:07.
This sound can be heard from 09:08
Sound is like whistle on a boiling kettle. I have no idea what comes first - strange noise or low pressure drop.
EXV unexpected closed?
I would appreciate any ideas about possible causes of these problems. Thanks in advance.
Sorry for my English.
It would be nice to see readings in English.May be undersized piping? Restriction? Trash stuck in liquid line?
Unfortunately, I dont have readings in English on video. We are using metric system in Ukraine.
Originally Posted by steveoo
I have a .csv file with recorded parameters from laptop, i will try to make a conversion to English system.
The piping remain the same from the previous chiller, it was EWLD240MBYNN with the same capacity.
I guess the pipe size are ok.
No dirt stuck inside - no temperature change on the pipe, and sight glass is full of liquid refrigerant.
Just a guess. No actual experience with that chiller. Loud tea kettle sound if coming from compressor could be internal relief valve opening or discharge check valve not holding at shutdown. Discharge pressure seemed to be accelerating near end of video. What diagnostics are you logging? Disable one circuit or current limit load to about 75% and see if chiller will stay running. Check for noncondensables. Check oil level. I have done startups where factory grossly overcharged oil, causing heat transfer problem. Walk condenser fan deck and make sure all fans turning proper direction and discharging upward.
Originally Posted by blacktigra
First time post on this site. I just watched the attached video, whist I am not intimately familiar with this model chiller, could the noise be Hot Gas Injection?
The noise appears to happen after a number of minutes running and the evaporating pressure is rather low at the time of the noise. I could be wrong (and this machine may not even be equipped with hot gas injection) but if it is, maybe that's what it could be.
deltap10, I also was thinking about internal pressure relief valve. The bigger pressure differential - the louder sound is.
Originally Posted by deltap10
I have logged all the parameters that controller can get from the sensors - pressures, temperatures. Unfortunately, I cant attach the .xls file to the post.
It will not help, because compressor capacity control doesnt work properly.
Originally Posted by deltap10
Also, this compressor dont have slide valve position feedback sensor, so if you have 75% percent on controller it does not mean that the compressor running at the 75%. Only if you calibrate load and unload pulse length, but i cant do it.
All that things have been checked.
Originally Posted by deltap10
This model doesnt have hot gas injection. Only liquid injection, but the solenoid valve on injection line is always closed.
Originally Posted by HVACRsaurus
Why does the Capacity on the top line go to 0%? What does this actually measure?
If it is what the computer is trying to make the chiller run to then why is it shutting the chiller off?
If it is just feedback from the CT or EXV position or ??? then why does it go to 0%?
A the end of the video, you mean? I switch off the compressor. There is no feedback from the solenoid slide valve.
Originally Posted by Wes G.
So, the problem have been solved. Maybe this information will be useful for somebody.
The main problem was in cheap chinese R134a refrigerant, which installer use to charge the system.
During commissioning I noticed a pressure drop on the shut-off valve on the suction side of compressor, before the moment when whistling noise is appear.
First idea was a mechanical dirt in suction filter, but when we remove it, filter was clean. After, we did a laboratory analysis of refrigerant at last, and were unpleasantly surprised by its results.
Laboratory didn't find any R134a in this refrigerant. It was a mixture of R22/R142b, air and moisture.
Moisture is freezing on mechanical filter on suction side, and that was a reason of that strange whistling noise.
When we replace the refrigerant, oil and oil filter chiller run perfect.
Wow. Thanks for the update. Do you have any idea, or suspicion, as to where or how this mix up happened?
This will be the second instance i have heard of bad 134a. In both instances refrigerant was not a major brand refrigerant. By major brand i mean dupont, allied, arkemia, etc. I have bought automotive 134a once to get out of a bind. Will not do that again. Moisture presence in the next oil sample went out of acceptable limits. Had to dehydrate and dry the entire charge.
It was unbranded fake "R134a refrigerant" from Chinese factory, which is cheaper than Dupont R134a, for example.
Originally Posted by Nuclrchiller