Trane Chiller

[dgruber]

CGAEC404ABA1R9 S/N J95A67962
We are getting a E4 error code at startup. Phase loss running

How does this Microprocessor monitor this information.

How can we bypass this for emergency run. until we verify sensor or transformer problems. Maybe a bad CT or connection.

The SW3 # 2 dip switch "power supply protection" Does this dip switch bypass this sensing of power.

We have verified all voltgae is correct and we have a phase monitor wired in to shut down the processer should we have a phase or power problem.

[tech cr]

Have you checked the "phase imbalance" between all 3phases? There is a formula in the manual..It shouldn't be more than 2 1/2 to 3 percent..

[maxster]

check the position of the CTs on the phases on top of the compressor contactors as per print shows repin them on UCP after ohming them also,also the phase tapping on the 2 TRs must be L1...L2 then the other L2...L3 that is phase reversal faults was this machine repaired and or running then faulting?if the compressors are the same tonnages the ohms on the CTs should be consistant.http://www.imagewiz.net/usr/hvac/2963_CTs.JPG the EXT is the last number on the white tag of the CT is the size if compressors are the same...the CTs should size the same way and ohm readings also.

[Edited by maxster on 04-06-2005 at 10:08 PM]

[dgruber]

This failure has benn going on for two weeks. But the system has manually reset.

Our technician just replaced two compressors on one circuit and the all the compressor contactors. The system began to start and the tech bypassed the low pressure control long enough to properly cherge the replced compressor circuit.

Some where during this time the machine shut down on the same itermittant error E4.

Trane provided the replacemnt compressors. the tech did check phase rotation and amperage. All is told to be correct. The tech disabled the new compressor circuit by removing the coil wire on both contactors, but still same error code. Only observation is the condensor fans monentarly pull in for a second with no compressor contactors pulled in, before failure.The compressors do not appear to even attempt to start.

We opened the Trane supply after hours last night to attempt to locate parts only to find the processor is obsolite and the boards are avalible by special order and told two boards are not avalible. I suspect the current transformers are triggering this condition.

More today as crunch time has approached.

[dgruber]

We had ohmed the CT's last night and all read the same. We did not have the values until now. Thanks Maxter!!

Trane local tell's us if we will need CT's we will have to order and rush them in.

How can we bypass this input to the Processor?

Can we go to Radio Shack and put matched fixed value resisters in place of the CT's?

[dgruber]

Now that we have the service bulletins from Trane.

I appears we may have a bad A6 board. This may have been the "on and off problem" for the last two weeks.

Trane say's we will need to air frieght.

Anyone have a way around this situation?

The liquid line solinolds are 13vdc. No manual stems to open them. No way to emergency run this chiller!!

[dgruber]

Luckely, we found this dip switch on this software revision E. This switch would disable the E6 diagnostic by placing the dip switch in the "on" position.

This has allowed us some time and now the system is back on line.

We have installed a external phase monitor and wired to the emergency external system shutdown terminals on the UCM.

[maxster]

take the sporlan numbers off the 13V coil,and get yourself the 115V coils if you want to do an external control of the unit..or leave them hot and run the compressors on a staged contol with sensing of the chilled water out.

[maxster]

if that is the one you got,i was going to give you the section on the A6 board checkout and the table 3:section three with the output ranges will check back latter if you need it.forget the CTS,did you check the grey ribbons in the backs of the boards with those tight bends...had those rub out with that random trip

[dgruber]

Well we took the guts out of one solinold valves, just so we could run one circuit the way you have mentioned.

The compressors need crankcase heaters to keep migration out of the scrolls,if we keep them that way.

The ribbon cable sounds like a great idea for us to check.

I just assume to return the A6 board and pay frieght, if our external phase monitor does the same trick.

Possibly as you have pointed out the ribbon cable may have rubbed bare enough or internally broken with the tight bend. A lot of vibration since 1995 start up.

[maxster]

even on the SWUDs the Macon guys use to worry on those bends and it could be just a "slight leak" onto the aluminum and there is your fault.sheet of cardboard or a strip of armaflex tape could do it as a cushion.with the scroll chillers it came up more with the panel in front of the compressors as it is.if you disconnect the 115V or the T side of the contactors that will give you your fault also,because the CT is looking for 5 seconds of amp draw to produce the resistance back into the UCP as proof of start.