Operating Theory
111
Cool
•
After initial start-up and pull-down to 1.0 C
(1.8 F) below setpoint, the controller calls for
the Cool mode whenever:
•
Return air temperature increases more
than 1.0 C (1.8 F) above setpoint.
•
Return air temperature is above setpoint
and the compressor has been off for 30
minutes.
•
Controller turns on the Compressor LED
when the compressor is operating.
•
Compressor must operate for a minimum of 5
minutes after startup.
•
After initial pull-down to setpoint, controller
keeps the In-range LED on as long as the
return air temperature remains less than 1.5 C
(2.7 F) above setpoint.
Null
•
The controller calls for Null when the return
air temperature decreases more than 1.0 C
(1.8 F) below setpoint.
•
The controller stops the compressor and
condenser fan.
•
The evaporator fans continue to operate
(except when Economy mode is on).
•
Compressor remains off for a minimum of 5
minutes.
Defrost
The evaporator coil sensor temperature must be
below 18 C (65 F) to initiate a Demand Defrost or
Manual Defrost. The evaporator coil sensor
temperature must be below 10 C (50 F) to initiate
a Timed Defrost.
•
Demand Defrost function initiates Defrost
immediately when:
•
Temperature difference between the return
air sensor and defrost (evaporator coil)
sensor is too large.
•
Temperature difference between the left
hand and right hand supply air sensors is
too large and unit has operated for more
than 90 minutes since last defrost.
•
Temperature difference between the
supply sensors and return air sensor is too
large.
•
Manual Defrost may be initiated immediately
by pressing the
D
EFROST
key or by REFCON
Remote Monitoring Modem (RMM).
•
A Timed Defrost always starts at 1 minute
past the hour immediately following a defrost
timer request for defrost. For example, if the
defrost timer requests a defrost cycle at 7:35,
the defrost cycle will start at 8:01. The
datalogger will record a Defrost event for each
log interval in which a Defrost cycle is
pending or active (i.e. both the 8:00 and 9:00
data logs on 1 hour logging interval).
•
On Chill Loads (setpoints at -9.9 C [14.1 F]
and above), the initial time interval is:
•
8 hours of compressor operation at supply
air temperatures of 5.1 C (41.2 F) or
above.
•
2.5 hours of compressor operation at
supply air temperatures of 5.0 C (41.0 F)
or below. One-half (0.5) hour is added to
A.
Cool
B.
In-range
C.
Null
1.
Decreasing Temperature
2.
Setpoint
3.
Increasing Temperature
Figure 58: Frozen Load Control Sequence
(Setpoints at -10 C [14 F] and Below)
Summary of Contents for 098916
Page 5: ......
Page 11: ...Table of Contents 10...
Page 19: ...Service Guide 18...
Page 28: ...Specifications 27 Figure 2 Physical Specifications AMA313...
Page 41: ...Unit Description Features Options 40...
Page 105: ...Operating Instructions 104...
Page 155: ...Servicing The Unit 154...
Page 187: ...Index 186...
Page 189: ...Wiring and Schematic Diagrams Index 188...
Page 190: ...189 Wiring Schematic...
Page 191: ...190 Wiring Diagram Page 1 of 2...
Page 192: ...191 Wiring Diagram Page 2 of 2...
