Start-Up (Cooling); Prestart Check List; Operating Instructions; Post Start Check List - York DM090 Installation Manual

127408-YIM-B-0606

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.
Unitary Products Group
OPERATING INSTRUCTIONS
This furnace is equipped with an automatic re-ignition
system. DO NOT attempt to manually light the pilot.

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 19).
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.
FIRE OR EXPLOSION HAZARD
Failure to follow the safety warning exactly could
result in serious injury, death or property damage.
Never test for gas leaks with an open flame. Use a
commercially available soap solution made specifi-
cally for the detection of leaks to check all connec-
tions. A fire or explosion may result causing property
damage, personal injury or loss of life.
2. Check for correct manifold gas pressures. (See 'CHECK-
ING GAS INPUT'.)
3. Check the supply gas pressure. It must be within the lim-
its shown on the rating nameplate. Supply pressure
should be checked with all gas appliances in the building
at full fire. At no time should the standby gas pressure
exceed 13 in. or the operating pressure drop below 5.0 in
for natural gas units. If gas pressure is outside these
limits, contact the local gas utility or propane supplier for
corrective action.

SHUT DOWN

1. Set the thermostat to the lowest temperature setting.
2. Turn "OFF" all electric power to unit.
45