Step 11 - Set The Outdoor Cooling And Heating Thermostats; Installation - Carrier COBRA 48/50HJ004-014 Installation And Service

Step 11 — Set the Outdoor Cooling and Heat-
ing Thermostats
IMPORTANT: The energy recovery section unit is shipped
with an outdoor thermostat set at 55 F which locks out
mechanical cooling on the RTU (rooftop unit) and the
energy recovery section compressor. If this feature is not
desirable, the rooftop unit's compressor can be allowed to
run by relocating both gray wires to the same side of the
Low Temperature Lockout Thermostat (LTLO) leaving the
white wire on the opposite pole, locking out only the energy
recovery section compressor. The LTLO is also accessible
by removing the filter access panel and the door of the
damper mounting bracket. Refer to Troubleshooting section.
KNOB
SCREWS (2)
HOOD
SIDE
END CAP
COOLING SET POINT
THERMOSTAT (WHITE LABEL)
TEMPERATURE SWITCH
SHIPPED WITH UNIT
Fig. 11 — Energy Recovery Section Supply-Air Hood Assembly
HOOD SIDE
45° LOCATION
Fig. 12 — Energy Recovery Section Barometric Exhaust Air Hood Assembly
ALUMINUM FILTER SCREEN
WIRE GUARD
30° LOCATION
DAMPER LIMITER
COOLING — During the unoccupied period, the economizer
mode of operation is used as the first stage of cooling. When
the outside air temperature is below the cooling thermostat set
point, the outside air will be used for first stage cooling.
HEATING — The heating thermostat should be adjusted
to the second stage balance point (heat output of the energy re-
covery section plus the heat output of the first stage on rooftop
unit equals building load at this temperature). Above this set-
ting, first stage heating will be the energy recovery section unit
and second stage will be the first stage of the rooftop unit.
Below this point first stage heating will be the energy recovery
section unit plus first stage heating of the rooftop unit. The sec-
ond stage will be the second stage of the rooftop unit.
HOOD TOP
HEATING POINT
THERMOSTAT
(RED LABEL)
29
DAMPER BLADE STOP
SHIPPED WITH UNIT
IN 45° POSITION
LTLO
MOUNTING
BRACKET
TEMPERATURE
COOLING
LOCKOUT (LTLO)
HOOD SIDE
SCREW INSTALLATION (2)
KNOB
HOOD TOP
HINGE
HINGE PIN
BAROMETRIC
RELIEF DAMPER
60° LOCATION
HOOD SIDE