Honeywell Q674F - Manual (Page 9)

9 69-0435—10
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HEATING
Move the system switch on the Q674 Subbase to
HEAT. Move the heating set point lever on the T874
Thermostat about 10
° F [6° C] above room tempera-
ture. Both stages of heating and fan should start. Move
the set point lever about 10
° F [6° C] below room
temperature. Heating and fan should shut off.
NOTE: To prevent compressor short cycling, a minimum
off-timer may be included to provide a five-minute time
delay before turning on the compressor after the thermo-
stat last turned off the compressor, or after the system
first received power. This delay protects the compressor.
COOLING
CAUTION
Do not operate cooling if the outdoor tempera-
ture is below 50
° F [10° C]. Refer to manufac-
turer recommendations.
Move the system switch on the Q674 Subbase to
COOL. Move the cooling set point lever on the T874
Thermostat about 10
° F [6° C] below room tempera-
ture. Cooling and fan should start (see CAUTION).
Move the cooling set point lever about 10
° F [6° C]
above room temperature. Cooling and fan should stop.
EMERGENCY HEAT
Change the system switch to EM. HT. The EM. HT.
LED will come on. The Q674F1410 Subbase starts the
electric strip heater(s) when put in the EM. HT. position
(see CAUTION in Subbase Setting section). All other
subbases will be tested by moving the set point lever
about 10
° F [6° C] above room temperature. The electric
strip heater(s) will come on. Reset the set point lever
about 10
° F [6° C] below room temperature. The electric
strip heater will de-energize. The EM. HT. LED remains
on until the system switch is moved to another position.
FAN
Move the subbase system switch to OFF, and the fan
switch to ON. The fan should run continuously. When
the fan switch is in the AUTO position, the fan operates
with the heating or cooling equipment.
Calibration
THERMOSTAT
T874 Thermostats are accurately calibrated at the
factory. They do not have provision for field calibration.
THERMOMETER
1. Remove thermostat cover by pulling the bottom
edge of the cover away from the base until it snaps free
from the retaining posts.
2. Set the cover on a table near an accurate thermometer.
3. After allowing 10 or 15 minutes for stabilization,
compare the readings. If they are the same, replace the
cover and put the system into operation. If they are
different, recalibrate the thermostat thermometer, step 4.
4. Insert a small screwdriver in the thermometer shaft
(Fig. 13) and turn it until the thermometers read the
same. When the thermometer is calibrated, replace the
cover and place the system into operation.
NOTE: Hand heat will offset the thermometer reading.
After making each adjustment, wait 10 or 15 minutes
for the thermometer to stabilize before comparing.
Fig. 13—Thermometer calibration.
M5070
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