YORK INTERNATIONAL
126
LOW AMBIENT CONDENSER FAN CONTROL
For unit operation below 25°F (-3.9°C) a low ambient
kit is required. The kit consists of a discharge pressure
transducer(s) and reversing contactors.
With the low ambient kit installed and the unit pro-
grammed for low ambient operation, the condenser fans
will operate as shown in Tables 23 and 24.
Again, notice that condenser fan operation can be pro-
grammed for either “temperature and discharge pres-
sure control,” or “discharge pressure control only” as
described under Condenser Fan Control.
The fan control on-pressure (ctrl_press) and the fan dif-
ferential off-pressure (diff_press) are programmable un-
der the PROGRAM key.
TABLE 23 – LOW AMBIENT CONDENSER FAN CONTROL – AMBIENT TEMPERATURE AND DISCHARGE
PRESSURE CONTROL
FAN STAGE
ON
OFF
FANS
Stage 1
OAT>25° F (-3.9°C)
OAT < 20° F (-6.7°C)
OR
AND
1 REV.
DP > ctrl_press
DP < ctrl_press - diff_press
Stage 2
OAT>45°F (-3.9°C)
OAT < 40°F
OR
AND
1 FWD.
DP > ctrl_press + 20 PSIG (1.38 Bars)
DP < ctrl_press - diff 20 PSIG (1.38 Bars)
Stage 3
OAT > 65°F (18.3°C)
OAT < 60°F
OR
AND
2 FWD.
DP > ctrl 40 PSIG (2.76 Bars)
DP < ctrl_press - diff 40 PSIG (2.76 Bars)
Unit Controls
FAN STAGE
ON
OFF
FANS
Stage 1
DP > ctrl_press
DP < ctrl_press - diff_press
1 REV.
Stage 2
DP > ctrl_press + 20 PSIG (1.38 Bars)
DP < ctrl_press - diff 20 PSIG (1.38 Bars)
1 FWD.
Stage 3
DP > ctrl 40 PSIG (2.76 Bars)
DP < ctrl_press - diff 40 PSIG (2.76 Bars)
2 FWD.
TABLE 24 – LOW AMBIENT CONDENSER FAN CONTROL – DISCHARGE PRESSURE CONTROL
Summary of Contents for MILLENNIUM YCUL0016SC
Page 35: ...YORK INTERNATIONAL FORM 150 63 NM1 35 This page is intentionally left blank 1 ...
Page 151: ...YORK INTERNATIONAL FORM 150 63 NM1 151 This page is intentionally left blank 5 ...
Page 155: ...YORK INTERNATIONAL FORM 150 63 NM1 155 This page is intentionally left blank 5 ...
Page 159: ...YORK INTERNATIONAL FORM 150 63 NM1 159 This page is intentionally left blank 5 ...
Page 163: ...YORK INTERNATIONAL FORM 150 63 NM1 163 This page is intentionally left blank 5 ...
Page 170: ...YORK INTERNATIONAL 170 ...