Carrier 19XR frame 5

[chillerguru]

Has anybody expierenced:
Alarm 247 DIFFUSER POSITION FAULT. If so please give me details. i did find a few service bulletins with information. what kind of failure have youve seen. is it more mechanical or electrical and alignment issues. has anbody expierence internal broken parts on the split ring diffuser. also why was the split ring diffuser added on the larger machine, was it just a capacity enhancement. im very familiar with the older 19xl and smaller 19xr machines to date back to the r22 19xl issues. please reply any information thanks.

[nique]

i've seen this once on a new startup, the wires were switched or terminated wrong. other then that I've never seen the alarm. another post from awhile back said that they had the coupling come loose. I dug up some info on it that you may have already looked at but will give it to ya anyway. keep us in the loop.

Confirm that Diffuser Option in SETUP 2 screen has not been enabled if compressor does not have a split ring diffuser. May indicate rotating stall condition.
Check rotating stall transducer wiring accuracy and sealing.
Check diffuser schedule and guide vane schedule in SETUP2 screen.
Check for proper operation of diffuser and inlet guide vane actuators including inlet guide vane calibration.
Check diffuser actuator coupling for rotational slip.
Check RC snubber on CCM J4-23 and J4-24.
Check 4.3k ohm resistor between CCM terminals J3-7 and J3-8.
Check for electrical noise in CCM Diffuser Pressure wiring. Do not continue to operate compressor except for diagnostic purposes.

The 19XR5 compressor has a split ring diffuser (SRD) that is coordinated with inlet guide vane position to provide efficient and reliable operation. If, for any reason, the IGVs and SRD aren’t coordinated, there is a chance for rotating stall which could lead to impeller tip breakage or bearing failure. To minimize the chance for such a failure the PIC controls have a transducer that senses pressure fluctuations at the tip of the impeller. If the control determines that there is rotating stall, it shuts the chiller down and displays Code 247, “PROTECTIVE LIMIT”, “DIFFUSER POSITION FAULT”. Do not restart the chiller until the cause of the alarm is determined. It is critical that a 19XR5 never be operated with the SRD control disabled (SETUP2, DIFFUSER CONTROL OPTION).

[Dallas Duster]

Is this chiller still under warranty?

[chillerguru]

out of warranty, in operation since 2003

[DITAW]

had one that would lose calibration, calibrate then lose it couple hours later. Long story short went into it and found the two bolts that hold the gear to rotate the diffuser were loose.

[my63volks]

had a new xrv with this alarm watch out for diff press transducer wiring like someone above said, drive was causing electrical noise. had to run in conduit

[nique]

talked to one of the "old boys" today and he said he ran into this problem not to long ago. had to give the control panel a better ground or in other words electrical noise. still since the unit is nine years old I would think transducer problems or something inside. maybe time to open it up.

[my63volks]

check coupling tightness and actuator calibration, noise suppresser, had to run signal to diff actuator in sealtite to get mine to stop . two xrv frame 5's side by side though like above said if this is an existing machine check calibration

[OpenDrive]

Had one that would do this intermittently every few days. Bad spot on the IGV motor pot. The IGV position would jump at certain times and give the fault. The diffuser motor gets a 4-20ma signal but has no feedback to the CCM. The IGV motor does, and the position of the 2 must match according to the scheduled set up in the Service menu or you will get the fault.