FORM 150.40-NM20
73
YORK INTERNATIONAL
YCHA RECIP. CHILLER
CONDENSOR FAN OPERATION
Some questions have arisen on YCHA Condensor Fan Operation. The confusion seems to be concerning the
temperature/pressure control scheme and whether temperature or pressure should be in command.
Temperatures Above 55°F As Sensed By the OAT (Outdoor Ambient Temperature) Sensor
Fan cycling will be by temperature control only, Discharge pressure will have no effect. Above 55°F. 4 sec. after the
respective compresssor starts, Fans E and F (Compr. 1) or Fans C and D (Compr. 2) will come on. Thirty sec. after
the respective compressor starts, Fans G and H(Compr. 1) or Fans A and B (Compr. 2) will come on. These fans will
remain on, regardless of discharge pressure or loading, until the respective compressor stops or temperature drops
below 55°F. Note: YCHA 120’s will not have Fan G.
Temperatures 35°F to 55°F As Sensed By the OAT (Outdoor Ambient Temperature) Sensor
In this range, 2 fans on each system are cycled by temperature control only. Discharge pressure will have no
effect on these 2 fans. Four (4) seconds after the respective compressor starts, Fans E and F (Compr. 1) or Fans
C and D (Compr. 2) will come on. These fans will remain on, regardless of discharge pressure or loading, until the
respective compressor stops or temperature drops below 35°F.
The other two fans on each system are cycled when the respective compressor is running according to discharge
pressure only. Fans G and H (Compr. 1) or Fans A and B (Compr. 2) will cycle according to table below until
temperature as sensed by the OAT sensor rises above 55°F, until the respective compressor stops, or temperature
drops below 35°F. Note: YCHA 120’s will not have Fan G.
Temperatures Below 35°F as Sensed By The OAT (Outdoor Ambient Temperature) Sensor
Below 35°F a Low Ambient Kit option must be installed. This kit will affect fan cycling below 35°F and 35°F to 55°F.
Details on this option will be discussed in another Service Bulletin. Without this kit, the chiller will not operate below
35°F.
If any doubts arise concerning the temperature the OAT sensor is sensing, display a Code 06 on the Micro Panel
Display. This display indicates the temperature sensed by the OAT sensor located outside on the back side of the
Logic section of the control panel. It should coincide with a thermometer located in the same location ± 10°F.
FAN FANS DlSCHARGE PRESSURE
SYSTEM
CONTACTOR CONTROLLED TO CYCLE FANS
“ON” “OFF”
1
5M E, F 260 LB. 190 LB.
6M G, H 280 LB. 210 LB.
2
7M C, D 260 LB. 190 LB.
8M A, B 280 LB. 210 LB.
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