York YCAL0080SC, YCAL0014SC manual Low Ambient Condenser Fan Control

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 41 and 42.

FORM 150.62-NM1

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 def- erential off-pressure (diff_press) are programmable un- der the PROGRAM key.

TABLE 41 – LOW AMBIENT CONDENSER FAN CONTROL – AMBIENT TEMPERATURE AND DISCHARGE PRESSURE CONTROL

FAN STAGE		ON	OFF
1	OAT >25° F (-3.9°C)		OAT < 20° F (-6.7°C)
		OR	AND
1 FAN REV
	DP > ctrl_press		DP < ctrl_press - diff_press
2	OAT >45°F (7.2°C)		OAT < 40°F (-4.40°C)
		OR	AND
1 FAN FWD
	DP > ctrl_press	+ 20 PSIG (1.38 Bars)	DP < ctrl_press - diff_press + 20 PSIG (1.38 Bars)
3	OAT > 65°F (18.3°C)		OAT < 60°F (15.6°C)
		OR	AND
2 FANS FWD
	DP > ctrl_press + 40 PSIG (2.76 Bars)		DP < ctrl_press - diff_press + 40 PSIG (2.76 Bars)

2

TABLE 42 – LOW AMBIENT CONDENSER FAN CONTROL – DISCHARGE PRESSURE CONTROL

FAN STAGE	ON		OFF
1
1 FAN REV	DP > ctrl_press		DP < ctrl_press - diff_press
2
1 FAN FWD	DP > ctrl_press + 20	PSIG (1.38 Bars)	DP < ctrl_press - diff_press + 20 PSIG (1.38 Bars)
3
2 FANS FWD	DP > ctrl_press + 40	PSIG (2.76 Bars)	DP < ctrl_press - diff_press + 40 PSIG (2.76 Bars)

YORK INTERNATIONAL 91