MODEL |
PLUG |
UTILITY RELAY * |
UTILITY SIGNAL
OPEN RELAY 
MODEL |
PLUG |
LLS |
187B / 180B
* SUPPLIED BY UTILITY PROVIDER | Liquid Line Solenoid |
A06526
Fig. 6 - 2-Stage Control Board
Evolution Controlled Low Ambient Cooling
This unit is capable of low ambient cooling down to 0_F
The Evolution Control provides an automatic evaporator coil freeze protection algorithm that eliminates the need for an evaporator freeze thermostat. Low ambient cooling must be enabled in the User Interface set up. Fan may not begin to cycle until about 40_F (4.4_C) OAT. Fan will cycle based on coil and outdoor air temperature.
Evolution controlled low ambient mode operates as follows:
—Fan is OFF when outdoor coil temp is less than outdoor air temperature (+3_F / 1.67_C) or outdoor fan has been ON for 30 minutes. (Fan is turned off to allow refrigerant system to stabilize.)
—Fan is ON when outdoor coil temp is more than outdoor air temperature (+ 25_F / 13.89_C) or outdoor coil temp is more than 80_F (26.67_C) or if outdoor fan has been OFF for 30 minutes. (Fan is turned on to allow refrigerant system to stabilize.)
—Low pressure switch is ignored for first 3 minutes during low ambient start up. After 3 minutes, if LPS trips, then outdoor fan motor is turned off for 10 minutes with the compressor running. If LPS closes within 10 minutes, then cooling continues with the outdoor fan cycling per the coil temperature routine listed above for the remainder of the cooling cycle. If the LPS does not close within 10 minutes, then the normal LPS trip response (shut down cooling operation and generate LPS trip error) will occur.
—The PWM output for both high and
Check Charge
Models 180B / 187B should be charged in high stage compressor operation. Factory charge amount and desired subcooling are shown on unit rating plate. Charging method is shown on information plate inside unit. To properly check or adjust charge, conditions must be favorable for subcooling charging. Favorable conditions exist when the outdoor temperature is between 70_F and 100_F (21.11_C and 37.78_C), and the indoor temperature is between 70_F and 80_F (21.11_C and 26.67_C). Follow the procedure below:
Unit is factory charged for 15ft (4.57 m) of lineset. Adjust charge by adding or removing 0.6 oz/ft of 3/8 liquid line above or below 15ft (4.57 m) respectively.
For standard refrigerant line lengths (80 ft/24.38 m or less), allow system to operate in cooling mode at least 15 minutes. If conditions are favorable, check system charge by subcooling method. If any adjustment is necessary, adjust charge slowly and allow system to operate for 15 minutes to stabilize before declaring a properly charged system.
If the indoor temperature is above 80_F (26.67_C), and the outdoor temperature is in the favorable range, adjust system charge by weight based on line length and allow the indoor temperature to drop to 80_F (26.67_C) before attempting to check system charge by subcooling method as described above.
If the indoor temperature is below 70_F (21.11_C), or the outdoor temperature is not in the favorable range, adjust charge for line set length above or below 15ft (4.57 m) only. Charge level should then be appropriate for the system to achieve rated capacity. The charge level could then be checked at another time when the both indoor and outdoor temperatures are in a more favorable range.
NOTE: If line length is beyond 80 ft (24.38 m) or greater than 20 ft (6.10 m) vertical separation, See Long Line Guideline for special charging requirements.
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