Low oil temperature YORK YCAJ 77SU7

[exxu]

The chiller has two circuits with JS64 compressors.
The problem is that the oil temperature in circuit 1 drops below the warning limit and the controller stops the circuit with "SYS1 LOW OIL TEMP".
The superheat is 7 C and the subcooling is 6 C. The type of refrigerant is R407C. The circuits have electronic expansion valves controlled by EKC 315A Danfoss.
The oil level is good, as vell as it's quality: the acidity test was negative.
The chiller is mounted "split" type: the air cooled condenser is outside and the cooler and compressors, inside.

[Grizzly]

The chiller has two circuits with JS64 compressors.
The problem is that the oil temperature in circuit 1 drops below the warning limit and the controller stops the circuit with "SYS1 LOW OIL TEMP".
The superheat is 7 C and the subcooling is 6 C. The type of refrigerant is R407C. The circuits have electronic expansion valves controlled by EKC 315A Danfoss.
The oil level is good, as vell as it's quality: the acidity test was negative.
The chiller is mounted "split" type: the air cooled condenser is outside and the cooler and compressors, inside.

The most common cause of this problem is the crankcase heater power supply has tripped.

Normally it is just a case of opening the relevant electrical cabinet and resetting the MCB.

Sometimes the actual C/Case Heater has failed.
When running (Compressor off) you should see the heater draw approx 1amp.

Another cause of this failure .... low oil temp.. is when the unit has been off for long enough for the oil temp to drop below ambient.

Or from shutdown the system has not been powered up long enough for the c/case heater to sufficiently heat the oil!

Most York Units look for a oil temp of 10c above ambient before allowing the system to start.
Grizzly

[exxu]

Thank you for the very fast response.
Those were the firdt things that i checked. The crankcase heater is ok: 1,2 Amps (it is active only when the compressor is stopped)
The oil temperature is about 35 C (they stopped the circuit for aproximate 24 hours, but it was energised) and the circuit works for about 1 or 2 hour (reaching the setpoint, stopping, and starting when the water warms up above the setpoint) and drops to a value that triggers the protection from the controller. Unfortunately the site is not near from me, and when i was there the chiller worked just fine. They called me and told me that the problem occured after i leaved.
The chiller was not stopped and the temperature of the room where the compressors are installed never drops below 15 C (in winter). The other circuit works well(the circuits share the same cooler).

[al]

Exxu

Either the ambient temp sensor or the oil temp sensor may be faulting intermittantly, although it seems more likely that you may have liquid floodback at some point in the process?

Al

[Grizzly]

Exxu

Either the ambient temp sensor or the oil temp sensor may be faulting intermittently, although it seems more likely that you may have liquid flood back at some point in the process?

Al

I totally agree,
Simply put either one of the 2 sensors if failing (intermittently) Or there is an actual temp drop in the oil.
If all else fails try an oil change + check the LWT sensor and Expansion valve operation.
Grizzly.

[exxu]

I totally agree,
Simply put either one of the 2 sensors if failing (intermittently) Or there is an actual temp drop in the oil.
If all else fails try an oil change + check the LWT sensor and Expansion valve operation.
Grizzly.
Will do. Thank you. In a few days i will go on the site.
Keep in touch.

[Grizzly]

Will do. Thank you. In a few days i will go on the site.
Keep in touch.

I forgot to mention the HISTORY BUTTON.
A VERY , VERY useful tool!

Pressing this and selecting 1,2 or 3.
Gives the status of the chiller at the last three faults.
With 1 being the most recent.

Press the history button below the PRINT Section.
No1 option will be displayed,
Press enter and scroll through the Chiller status at the time of the latest Alarm event.

If you wish to view either of the 2 previous press the relevant no after the history button but prior to pressing enter.

You will then be able to see which parameter is at fault (hopefully) at the time of the fault.
Grizzly

[centrifs]

I am not sure about the split system YCAJ but the packaged chillers usually have a 1/4 " oil cooling solenoid valve mounted on left side, have seen these leak thru quite alot. also those danfoss 315a S1 sensors can be a problem. When you say 7 deg superheat is that measured or from danfoss display?? get the manual on the 315a , alot of info in those drop down menus!!! swap your two oil temp sensors and see if the problem travels.
I dont think the OA sensor will stop a system that is running for "SYS1 LOW OIL TEMP". it would prevent it restarting. like grizzly said needs to be 10 deg over ambient.
good luck

[Taffy]

We had simular problems years ago when I worked for York, we were working on gold standards that were intermitantly going out on oil failure, we had to replace the Capiliary lines on the oil pressure switch to cure the problem, It worked! May as well try it as its a low cost solution that may work for you.

[exxu]

The problem seems to be solved by adjusting the PID of the controller. It works fine for 10 days now. I hope the phone won't ring again for that problem.