7
Scholar V Installation & Startup Manual 07/2016 New
1.03 STANDARD CONTROLS
A. High and Low Refrigerant Pressure and Loss of Charge Switches
These switches render the compressor and outdoor fan motor inoperative whenever
the limits of the pressure switches are exceeded. In the event of high pressure, the
Scholar V heat pump or air conditioner will turn off and lockout.
The low pressure (A/C) and loss of charge (HP) switch is bypassed for 8-1/2 minutes
during each start-up. The system will lockout if the low pressure switch opens three
times within one hour or if it does not reset within 8-1/2 minutes of the Scholar V
heat pump or air conditioner start-up.
The high and low pressure and loss of charge switches are resettable at the wall
thermostat or by turning power off and then on to the Scholar V heat pump or air
conditioner. A fault LED located on the PLC indicates that a lockout has occurred
and whether it is due to high or low refrigerant pressure.
B. Heat Related Controls
The
outdoor thermostat (heat pump only)
, factory set at 40°F, determines the
temperature at which the supplemental electric heat (or wet heat) turns on to heat
the classroom. The temperature set point can be adjusted in the field for local
conditions. When the outdoor thermostat activates electric heat, the compressor
simultaneously turns off.
The
electric heat control (heat pump only)
operates only when a preset outdoor
temperature is reached. Electric heat can also operate upon request from the control
setting for emergency heat.
The
electric heat during defrost (heat pump only)
is programmed to operate
during defrost.
C. The motorized fresh air damper with PowerVent and GreenWheel
®
ERV
ventilation options are equipped with a
fresh air fan speed control
. The fresh air
fan speed control controls both the ventilation intake and exhaust blowers together,
automatically balancing the intake and exhaust cfm up to 450 cfm. An optional fan
speed control allows independent operation of the intake and exhaust air blowers.
IMPORTANT
MINIMUM AIR FLOW IS REQUIRED FOR PROPER OPERATION.
