Carrier 50EJQ Installation, Start-Up And Service Instructions Manual page 26

SET POINT FORMAT
OHSP
OCSP
UHSP
UCSP
SASP
OATL
NTLO
RTIO
LIMT xx.x^F
MDP
LOWMDP
IAQS
UHDB xx.x^F
UCDB xx.x^F
LTMP
HTMP
PES1
PES2
DEFRTIME xxmin.
LEGEND
CV — Constant Volume
IAQ — Indoor Air Quality
N/A — Not Available
OAT — Outdoor-Air Temperature
NOTE: Computer access may be required to change set points.
Heating —
The control module is powered by 24 vac. If
the unit is controlled with a room sensor, the fan will run
continuously in the Occupied mode, with the outside-air damper
in the minimum position. If the unit is controlled through a
room thermostat (with FAN set to AUTO), upon a call for
heat the first stage heat is energized, energizing reversing
valve solenoids (RVS1 and 2). Compressor no. 1 and 2, in-
door and outdoor-fan motors start. Upon a call for additional
heat (if equipped with electric heaters), the second stage of
heat is energized. When the call for heat is satisfied, the com-
pressors, fan motors, and heaters will be deenergized and
the outdoor-air damper will move to the closed position.
If the unit is controlled with a room sensor the fan will
not run in the Unoccupied mode unless the space temper-
ature is below the unoccupied heat set point or above the
unoccupied cool set point. Upon a call for heat, the first
stage of heat is energized, energizing reversing valve sole-
noids (RVS1 and 2). Compressor no. 1 and 2, indoor and
outdoor-fan motors start, and the outdoor-air damper will move
to the Unoccupied IAQ position (generally set to zero in the
Unoccupied mode). The IAQ feature is enabled through sys-
tem software. Upon a call for additional heat (if equipped
with electric heaters), the second stage of heat is energized.
When the call for heat is satisfied, the compressors, fan
motors, and heaters will be deenergized and the outdoor-air
damper will move to the closed position.
Defrost Cycle —
When the temperature of the outdoor
coil drops below 28 F as sensed by the defrost thermostat
(DFT1 or 2) and the defrost timer is at the end of a timed
period (adjustable at 30 to 90 minutes) the defrost cycle will
begin. See Fig. 34. The control board will deenergize the
reversing valve solenoids (RVS1 and 2) and energize the elec-
tric heat. Also, the outdoor-fan motor will stop.
The unit will continue to defrost until the coil temperature
as measured by DFT1 and 2 reaches 65 F or the duration of
defrost cycle completes a 10-minute period.
Table 14 — User Defined Set Points
xx.xF Occupied Heat Set Point
xx.xF Occupied Cool Set Point
xx.xF Unoccupied Heat Set Point
xx.xF Unoccupied Cool Set Point
xx.xF Supply Air Set Point
xx.xF Hi OAT Lockout Temperature
xx.xF Unoccupied OAT Lockout Temperature
xx.x
xxx% Minimum Damper Position
Low Temperature Minimum
xxx%
Damper Position Override
xxxx
Unoccupied Heating Deadband
Unoccupied Cooling Deadband
xxx% Low Temp. Min. Position
xxx% High Temp. Min. Position
xxx% CV Power Exhaust Stage 1 Point
xxx% CV Power Exhaust Stage 2 Point
Defrost Cycle Time
DESCRIPTION
Reset Ratio
Reset Limit
IAQ Set Point
Fig. 34 — Defrost Temperature
During the defrost mode, if a circuit defrosts first, the RVS
will oscillate between heating and cooling modes until de-
frost mode is complete. This will keep the head pressure on
that circuit from getting too high.
At the end of the defrost cycle, the electric heaters will be
deenergized, reversing valve solenoids will be energized, and
the outdoor fan will start.
26
LIMITS
55 to 80 F
55 to 80 F
40 to 80 F
75 to 95 F
45 to 70 F
55 to 75 F
40 to 70 F
0 to 10
0 to 20° F
0 to 100%
0 to 100%
1 to 5000 ppm
0 to 10° F
0 to 10° F
0 to 100%
0 to 100%
0 to 100%
0 to 100%
30 to 90 minutes
Thermostat Location
DEFAULT
68 F
78 F
55 F
90 F
55 F
65 F
50 F
N/A
N/A
N/A
100%
650 ppm
1° F
1° F
10%
35%
25%
75%
50 minutes