127878-YIM-C-1208
58 Johnson Controls Unitary Products
START-UP (COOLING)
PRESTART CHECK LIST
After installation has been completed:
1. Check the electrical supply voltage being supplied. Be
sure that it is the same as listed on the unit nameplate.
2. Set the room thermostat to the off position.
3. Turn unit electrical power on.
4. Set the room thermostat fan switch to on.
5. Check indoor blower rotation.
• If blower rotation is in the wrong direction. Refer to
Phasing Section in general information section.
• Check blower drive belt tension.
6. Check the unit supply air (CFM).
7. Measure evaporator fan motor's amp draw.
8. Set the room thermostat fan switch to off.
9. Turn unit electrical power off.
OPERATING INSTRUCTIONS
1. Turn unit electrical power on.
NOTE: Prior to each cooling season, the crankcase heaters
must be energized at least 10 hours before the sys-
tem is put into operation.
2. Set the room thermostat setting to lower than the room
temperature.
3. First stage compressors will energize after the built-in
time delay (five minutes).
4. The second stage of the thermostat will energize second
stage compressor if needed.
POST START CHECK LIST
1. Verify proper system pressures for both circuits.
2. Measure the temperature drop across the evaporator
coil.
START-UP (GAS HEAT)
PRE-START CHECK LIST
Complete the following checks before starting the unit.
1. Check the type of gas being supplied. Be sure that it is
the same as listed on the unit nameplate.
2. Make sure that the vent outlet and combustion air inlet
are free of any debris or obstruction.
OPERATING INSTRUCTIONS
LIGHTING THE MAIN BURNERS
1. Turn “OFF” electric power to unit.
2. Turn room thermostat to lowest setting.
3. Turn gas valve counter-clockwise to “ON” position (see
Figure 36).
4. Turn “ON” electric power to unit.
5. If thermostat set temperature is above room tempera-
ture, the main burners will ignite. If a second stage of
heat is called for, the main burners for second stage heat
will ignite for the second stage heat.
POST START CHECKLIST
After the entire control circuit has been energized and the
heating section is operating, make the following checks:
1. Check for gas leaks in the unit piping as well as the sup-
ply piping.
TABLE 38: GAS HEAT ANTICIPATOR SETPOINTS
SETTING, AMPS
W1 W2
0.65 0.1
FIGURE 35 : TYPICAL FLAME
H E A T E X C H A N G E R T U B E
G A S
S U P P L Y
P I P E
B U R N E R
B U R N E R B R A C K E T
I G N I T O R
B U R N E R F L A M E
( B L U E O N L Y )
This furnace is equipped with an automatic re-ignition
system. DO NOT attempt to manually light the pilot.
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