York YCH120 User Manual

YORK INTERNATIONAL
68
RECIP CHILLER MICRO PANELS
GE II .5 EPROM
REVISION LEVEL CHANGE TO GE II.5 REV. 2*
For the past 3 years, the standard EPROM in both water cooled and air cooled Recip. Chillers 120 tons and above
has been GE II.5 REV. 0 or REV. 1. Both of these EPROM’s are interchangeable and their operation is transparent
to the user. The only important difference is the low motor current cut-out point (REV. 0 = 29%, REV. 1 = 23%). The
cut-out point was lowered to enable 6 cyl. compressors, which unload to 2 cylinders, to operate under certain very
low load / temperature conditions;
A new GE II .5 REV. 2 EPROM will begin appearing in our new U.L. approved water and air cooled chillers above
120 tons. These chillers will have cost reduced micropanels with a Combo Board replacing the Motor Current Board,
Analog Input Board, and Power Supply Board. A small quantity of non U.L. units with this new EPROM will also be
built. These units will also have the cost reduced micropanel and can be identified by the presence of the Combo
Board.
The GE II.5 REV. 2 EPROM will assume the old part number of the REV. 0 and REV. 1 (031-00928-001) and replace
them as a Service Parts replacement. Should the need arise to replace an EPROM, the new REV. 2 EPROM will be
an exact replacement on all water cooled units (LCH 130 - 230, YCWK - YCWT) which used REV. 0 and REV. 1
EPROM’s and came equipped with Analog Input, Power Supply and Motor Current Boards. However, if for some
reason an EPROM requires replacement on an Air Cooled Chiller (YCHA 120 - 200, YCAG - YCAN) equipped with
Analog Input, Power Supply and Motor Current Boards, a modification will be required to permit proper operation of
the fans. This modification should be performed as follows:
1. Place SW2 on the Micrologic Board to the ON position (Right side pushed down). This enables
manual adjustment of the low ambient cut-out.
2. Select Display Code 0,7 on the Control Panel to view the low ambient cut-out.
3. Adjust R24 on the Analog Board until the low ambient cut-out on the display is as low as it will go
(Typically 0 or 0.1°F).
4. Disconnect the J17 plug from the Analog Input Board. This causes the micro to sense outside air
temperature as 1°F.
5. The micro is now fooled into thinking that outside air temperature is very low and will now cycle
fans according to discharge pressure only (not temperature). Fan cycling will operate as follows:
* GE II.5 REV. 2 EPROMS may also be labeled.
GE II.5S REV. 2 The two EPROMS are indentical.
System 1 System 2
ON: Condenser Press 260 PSI ON: Condenser Press 260 PSI
FAN FAN
E & F C & D
OFF: Condenser Press 210 PSI OFF: Condenser Press 190 PSI
ON: Condenser Press 280 PSI ON: Condenser Press 280 PSI
FAN FAN
*G & H A & B
OFF: Condenser Press 210 PSI OFF: Condenser Press 210 PSI
*Fan “G” not present on all chillers.
Failure to perform the modifications described will result in potential low discharge pressures and corresponding low
suction pressures in outside ambient temperatures of 45 - 65°F. This will definitely cause low suction pressure and
low motor current faults. Symptoms indicating that this modification has not been performed will be all 4 fans on a
system starting 5 sec. after compressor start in ambient temperatures above 45°F.
In general, the REV. 2 EPROM functions the same as the REV. 0 and REV. 1 except for fan cycling. Even fan cycling
remains much the same except that the wiring has changed on U.L. air cooled chillers and requires the REV. 2
EPROM. Detailed operation of the new software is contained in FORM 150.24-NM25 and 150.40-NM25.

York YCH120 Specifications

General

Brand	York
Model	YCH120
Category	Chiller
Language	English