Table of Contents
Advertisement
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.
TABLE 23 – LOW AMBIENT CONDENSER FAN CONTROL – AMBIENT TEMPERATURE AND
DISCHARGE PRESSURE CONTROL
FAN STAGE
OAT>25° F (-3.9°C)
Stage 1
OAT>45°F (-3.9°C)
Stage 2
DP > ctrl_press + 20 PSIG (1.38 Bars)
OAT > 65°F (18.3°C)
Stage 3
DP > ctrl_press + 40 PSIG (2.76 Bars)
TABLE 24 – LOW AMBIENT CONDENSER FAN CONTROL – DISCHARGE PRESSURE CONTROL ONLY
FAN STAGE
Stage 1
Stage 2
DP > ctrl_press + 20 PSIG (1.38 Bars)
Stage 3
DP > ctrl_press + 40 PSIG (2.76 Bars)
YORK INTERNATIONAL
ON
OR
DP > ctrl_press
OR
OR
ON
DP > ctrl_press
Again, notice that condenser fan operation can be pro-
grammed for either "temperature and discharge pressure
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.
OFF
OAT < 20° F (-6.7°C)
AND
DP < ctrl_press - diff_press
OAT < 40°F
AND
DP < ctrl_press - diff_press + 20 PSIG (1.38 Bars)
OAT < 60°F
AND
DP < ctrl_press - diff_press + 40 PSIG (2.76 Bars)
OFF
DP < ctrl_press - diff_press
DP < ctrl_press - diff_press + 20 PSIG (1.38 Bars)
DP < ctrl_press - diff_press + 40 PSIG (2.76 Bars)
FORM 150.63-NM2
3
FANS
1 REV.
1 FWD.
2 FWD.
FANS
1 REV.
1 FWD.
2 FWD.
125
Advertisement
Table of Contents
