York J Series - Unit Checks - Power Applied; Initial Start-Up; Gas Heat Models Staged

FORM 100.50-NOM7 (808)
15
JOHNSON CONTROLS
2
17. If applicable, verify installation of air lters (refer
to Installation section for size and quantity).
18. Verify Variable Frequency Drive setpoints for VAV
units and optional Variable Frequency Drive Ex-
haust Fan and optional head pressure control. The
supply fan VFD is located in the supply fan section
of the unit. The optional head pressure control VD
is located next to the supply fan VFD. The power
exhaust VFD is located in the return air section next
to the exhaust motor. Refer to separate manual for
VFD operation and programming, supplied with
the rooftop unit.
UNIT CHECKS – POWER APPLIED
1. Apply 3-phase power and verify its value. Volt-
age imbalance should be no more than 2% of the
average voltage.
2. Verify programmed units Setpoints.
3. Verify correct fan rotation – fan should rotate in
direction of arrow on fan housing.
4. Insure proper compressor rotation.
5. Insure proper condenser fans rotation.
INITIAL START-UP
After all of the preceding checks have been completed
and the control panel has been programmed as required,
the unit may be placed into operation.
1. Place the Unit Switch in the control panel to the
RUN position.
2. With a demand, the supply fan will cycle on, and
permit compressor operation if the air proving pres-
sure switch for the supply fan has closed.
3. The rst compressor will start. After several minutes
of operation, a ow of refrigerant will be noted in
the sight glass, the vapor in the sight glass will clear,
and there should be a solid column of liquid visible
in the sightglass when the TXV stabilizes.
4. Allow the compressor to run a short time, being
ready to stop it immediately if any unusual noise
or adverse conditions develop.
5. Check the system operating parameters. Do this
by selecting various displays such as pressures and
temperatures (where available) and comparing these
readings to pressures and temperatures taken with
manifold gauges and temperature sensors.
6. With an ammeter, verify that each phase of the con-
denser fans, compressors, supply fan, and exhaust
fan are within the RLA/FLA as listed on the unit
data plate.
GAS HEAT MODELS "STAGED"
Pre-Start Checks:
• Startup of gas heat includes verication of incoming
gas line pressure, and leak checks in the eld in-
stalled gas lines. These checks are the responsibility
of the installing contractor, but should be veried
prior to unit startup.
• Verify wiring inside the burner compartment to
insure the wiring/terminals are tight and securely
connected to the components, such as the ignition
control, ame sensor, gas valve, rollout switches
and igniter.
• Check that the transformer is wired for the correct
voltage (the transformer has 2 taps, one for 208 volts
and one for 240 volts); check that the wire terminal
is on the correct terminal on the transformer (on 208
volt units, the tap should be on the 208 term of the
trans; for all other voltages, it should be on the 240
volt terminal).
Post Start Checks:
• When a signal is received at the gas heat control
module from the DCU, verify:
• Combustion blower starts and runs for 30 secs;
• Spark igniter sparks continuously;
• Gas valve opens;
• Burners light from right to left, in a 2-5 second
time frame, that each one lights in sequential
order from right to left, establishes stable ame
immediately upon ignition;
• Flame is stable, with ignition starting at the end
of the burner and that no burning is occurring
inside the burner;
• Ignition control operation is as follows:
• Once the control receives a signal from the
DCU for heat, the combustion blower starts
for a 30 sec pre-purge;
• The spark igniter is then energized with the
gas valve opening; it will try for ignition for
7 secs;
• The control will look for the remote ame
sensor proving ame;
• If it does prove, the burners will continue; if
not, the gas valve will be closed, there will be
a 30 second purge period; the igniter will again
energize and gas valve will open for 7 secs;
there will be 3 tries for ignition; after 3 tries,
the control will lock out;