Carrier 50DF034 - Manual (Page 11)

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HEATING
LEVER(RED)
COOLING
LEVER (BLUE)
THERMOSTAT
CAPTIVE TERMINAL MOUNTING SCREWS
THERMOSTAT/TRANSMITTER
Fig. 15 — Electronic Thermostat/Transmitter (without subbase)
(Which must be ordered as an accessory)
To Shut Off Unit— For standard units, set the subbase
selector switch to OFF or set the cooling temperature
selector lever above room temperature. For units with
energy management accessory, set the cooling tem­
perature selector switch above room temperature.
Do not shut off unit circuit breakers except when unit
is serviced. Crankcase heater is energized onlv when unit
power is on.
HEATING (Electric Heat Units)
1. Turn on unit power; set circuit breakers at ON.
2. On units with energy management accessory, position
the HEAT SETBACK SELECT switch in the set-
back/setup module to the desired position (5°, 10°,
15°). See Fig 14
3. Move the thermostat or transmitter heating set point
(red lever) above room temperature The heating LED
on the left-hand side of thermostat or transmitter
should begin to glow. Electric heat should cycle on.
Check supply duct outlets for heat. If heating equip­
ment does not cycle on, see Service, Electronic Com­
ponent Checkout.
4. Move the heating set point below room temperature.
The heating equipment should cycle off and the heating
LED intensity should decrease to a faint glow or go
off completely.
5. Return the heating and cooling set points to desired
settings and lock in place. On standard units, return
subbase switch to desired position. On units with
energy management accessory, an adjustable morning
warm-up thermostat is used to hold dampers closed
until return air reaches the setting on the thermostat
located in the night setback box.
To Shut Off Unit — Standard units, set the subbase
selector switch to OFF or set the heating temperature
selector lever below room temperature. For units with
energy management accessory, set the heating tempera­
ture selector switch below room temperature
AUTOMATIC CHANGEOVER — Standard units
automatically switch from heating to cooling mode when
the subbase selector switch is set at AUTO, and the
temperature of the conditioned space rises to the cooling
selector lever setting When the temperature of con­
ditioned space falls to heating selector lever setting, the
unit automatically changes from cooling mode to heat­
ing mode.
The thermostat and unit are so connected that cooling
and heating systems do not operate simultaneously.
On units with energy management accessory, with
dual set point thermostat or transmitter, changeover is
also automatic. There is a minimum 3 F deadband
between the heating and cooling set points
ECONOMIZER OPERATION — If unit is equipped
with modulating outdoor air control (economizer), set
enthalpy control (Fig. 4 and 8) at “A.” Unit capability
to integrate economizer with mechanical cooling allows
for a higher changeover point than conventional econo­
mizer systems. Because of this, outside air is desired
whenever its enthalpy (total heat content) is below return
air enthalpy. Typical return air conditions, shaded
portion of Fig. 9, indicate that setting “A” should be
used for maximum operating economy.
OPERATING SEQUENCE WITH ECONOMIZER
(without energy management accessory) using thermo­
stat with subbase.
Cooling — System switch set at AUTO, or COOL, fan
switch at ON or AUTO, (indoor air fan runs inter­
mittently). Thermostat set at desired setting.
When thermostat calls for cooling and outdoor air
enthalpy is below setting of enthalpy controller, the
economizer modulates open. (If outdoor air enthalpy is
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