SB0006 101
File In: None
Affected
ESG SERVICE BULLETIN Equipment: YCAS Style “D” Air Cooled Chillers
Subject: EPROM Retrofit to add Recycling Pumpdown
Issue Date: Withdrawal Date: N/A Data Control Level: C
Materials Needed: Issue Date:Issue
Replacement EPROM(s) as required
Tools Required: Basic Hand Tools
Estimated Time Required:
Warranty: Yes
Revision Notes: None
GENERAL
Following extensive field trials, an EPROM software upgrade has been made to add a recycling pumpdown feature
similar to the recip chiller modifications made a few years ago. Subsequently, a retrofit should be made to all
YCAS Style D Air Cooled Chillers currently operating in the field as quickly as possible. This enhancement
provides improved pumpout of liquid refrigerant in both the evaporator and the motor housing. Presently, the
software only provides for a pumpdown on shutdown. The new software will periodically initiate recycling
pumpdown in addition to the pumpdown on shutdown. The addition of the recycling pumpdown will reduce the
potential for slide valve bolt breakage, drive gear breakage, and motor failure due to liquid slugging from refriger-
ant buildup in the evaporator or the accumulation of liquid in the motor housing when a compressor is idle.
All chillers, not already upgraded through direct contact with YORK Factory Service since June of 2000, should be
modified to assure our customers receive the maximum life from our product. The upgrade is also “required”
before the factory will provide any future warranty consideration for compressor failures.
RECYCLING PUMPDOWN and PUMPDOWN ON SHUTDOWN OPERATION
System pumpdown will normally occur at shutdown and not at start-up. When the compressor is shutdown under a
controlled shutdown on satisfied cooling demand, the micro will close the liquid line solenoid valve, fully unload
the compressor, and the compressor will pump the system down to the suction pressure cutout before the compres-
sor turns off. A pumpdown failure safety assures that the pumpdown to cutout on shutdown does not fail due to a
leaking liquid line solenoid, by limiting pumpdown length to 3 minutes. If pumpdown is not achieved, the compres-
sor will turn off. Three successive failed pumpdown attempts will cause the system to lock out on a manual reset
“pumpdown failure” safety.
Work on this equipment should only be done by properly trained personnel who are qualified to work on this
type of equipment. Failure to comply with this requirement could expose the worker, the equipment and the building
and its inhabitants to the risk of injury or property damage.
The instructions on this service bulletin are written assuming the individual who will perform this work is a fully
trained HVAC & R journeyman or equivalent, certified in refrigerant handling and recovery techniques, and knowl-
edgeable with regard to electrical lock out/tag out procedures. The individual performing this work should be aware
of and comply with all national, state and local safety and environmental regulations while carrying out this work.
Before attempting to work on any equipment, the individual should be thoroughly familiar with the equipment by
reading and understanding the associated service literature applicable to the equipment. If you do not have this
literature, you may obtain it by contacting a York Service Office.
Should there be any question concerning any aspect of the tasks outlined in this bulletin, please consult a York
Service Office prior to attempting the work. Please be aware that this information may be time sensitive and that
York International reserves the right to revise this information at any time. Be certain you are working with the latest
information. The York Service office nearest you may be found on the Internet at www.york.com.
SB0006
The software upgrade will only initiate recycling pumpdown when a compressor has been OFF for 45 minutes, is
able to run with no safeties affecting it, no cooling demand is present, and any one of the following conditions are
met:
Saturated Suction Temp > LCHLT – 1.5°F (0.83°C) (If ambient temp is greater than LCHLT – 5.9°F [3.3°C])
OR
After the compressor has been idle for 45 minutes and the suction pressure is > Suction Pressure
Cutout. A recycling pumpdown will be initiated 45 minutes later (default) or as based on a user pro-
grammed Delay under the PROGRAM key.
PARTS
EPROM’s should be ordered the from Baltimore RPC according to the number of compressors on the chiller.
PART VERSION CHECKSUM
2 Compressor R22: 031-01714-001 C.ACS.01.02 FDF7
3 Compressor R22: 031-01714-103 C.ACS.03.03 A41D (ORDER 2 EPROM’S PER CHILLER)
4 Compressor R22: 031-01714-105 C.ACS.05.04 611C (ORDER 2 EPROM’S PER CHILLER)
INSTALLATION
Prior to installing the new EPROM, record all user programmable values. These values may be lost when the new
EPROM is installed. Remove power and carefully remove the old EPROM. Install the new EPROM with the
notch in the same orientation as the original and as indicated by the silk screening on the circuit board. Power the
system up and reprogram any setpoints that have been lost, along with the programmable time, which affects the
recycling pumpdown.
SYSTEM INFORMATION and CHECKS
System information and checks should be recorded as detailed on the attached System Check Sheet. Check Sheets
must be filled out and faxed to 717-771-6844. Allowed warranty costs for performing the retrofit will include the
EPROM or EPROM(S), plus up to 1 hour labor per compressor (if needed), plus travel time (if needed). The
completed System Check Sheet must be returned before a warranty claim for the work will be accepted. This check
sheet must be on file before any future warranty claims will be accepted.
2 YORK INTERNATIONAL
SB0006
SYSTEM CHECK SHEET FOR YCAS STYLE “D” UNITS
(Fax this form to: 717-771-6844 – Attention: Mike Greiman)
Site Information
Site job name____________________________________ Warranty #_____________
Location_________________________________________
Unit Information
Chiller Model_____________________________ Y-D or ACL Start? (Circle One)
Chiller Serial Number______________________ Start Date________________________
Chiller Duty: Comfort Cooling Process Cooling (Circle One)
Compressor Model/Serial #: 1:__________, 2:__________, 3:___________, 4:__________
Has there been a prior compressor failure? Yes No (Circle One)
Which type of compressor failure? Mechanical Electrical (Circle One)
History – run hours / number of starts
Run Hours Number of Starts
System No 1 _____________ ______________
System No 2 _____________ ______________
System No 3 _____________ ______________
System No 4 _____________ ______________
System Checks (Circle one per system)
System 1 System 2 System 3 System 4
Is the compressor heater working? Yes No Yes No Yes No Yes No
Is each compressor loading/unloading? Yes No Yes No Yes No Yes No
(Motor current changes as compressor
loads/unloads)
Is the compressor unusually noisy? Yes No Yes No Yes No Yes No
Are all the fans operating correctly? Yes No Yes No Yes No Yes No
Any other comments on unit operation? _____________________________________
________________________________________________________________________
Signed_____________________________ Date______________
YORK INTERNATIONAL 3
