Operation - York PCG4 Series Installation Manual

Table 13: Additional Static Resistance
Size (Tons) CFM Wet Indoor Coil Economizer
500 0.01
600 0.01
700 0.01
800 0.02
024 (2.0)
900 0.03
1000 0.04
1100 0.05
1200 0.06
700 0.01
800 0.02
900 0.03
030 (2.5) 1000 0.04
1100 0.05
1200 0.06
1300 0.07
700 0.01
800 0.02
900 0.03
1000 0.04
036 (3.0)
1100 0.05
1200 0.06
1300 0.07
1400 0.08
1100 0.02
1200 0.03
1300 0.04
1400 0.05
1500 0.06
042 (3.5)
1600 0.07
1700 0.07
1800 0.08
1900 0.09
2000 0.09
1100 0.02
1200 0.03
1300 0.04
1400 0.05
1500 0.06
048 (4.0)
1600 0.07
1700 0.07
1800 0.08
1900 0.09
2000 0.09
1100 0.02
1200 0.03
1300 0.04
1400 0.05
1500 0.06
060 (5.0)
1600 0.07
1700 0.07
1800 0.08
1900 0.09
2000 0.09
1. The pressure drop through the economizer is greater for 100% outdoor air
than for 100% return air. If the resistance of the return air duct is less than
0.25 IWG, the unit will deliver less CFM during full economizer operation.
2. Filter pressure drop based on standard filter media tested at velocities not
to exceed 300 ft/min.
Johnson Controls Unitary Products
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Filter/Frame Kit
0.00 0.01
0.00 0.02
0.00 0.04
0.01 0.06
0.01 0.08
0.01 0.10
0.01 0.13
0.02 0.16
0.00 0.04
0.01 0.06
0.01 0.08
0.01 0.10
0.01 0.13
0.02 0.16
0.03 0.17
0.00 0.04
0.01 0.06
0.01 0.08
0.01 0.10
0.01 0.13
0.02 0.16
0.03 0.17
0.04 0.18
0.02 0.04
0.02 0.04
0.02 0.05
0.03 0.05
0.04 0.06
0.04 0.07
0.04 0.08
0.04 0.09
0.05 0.10
0.05 0.11
0.02 0.04
0.02 0.04
0.02 0.05
0.03 0.05
0.04 0.06
0.04 0.07
0.04 0.08
0.04 0.09
0.05 0.10
0.05 0.11
0.02 0.04
0.02 0.04
0.02 0.05
0.03 0.05
0.04 0.06
0.04 0.07
0.04 0.08
0.04 0.09
0.05 0.10
0.05 0.11
SECTION VI: OPERATION
The unit is controlled by a conventional heating/cooling thermostat. If an
electronic thermostat is used, make sure it has a common connection.
DO NOT use a power stealing thermostat.
HEATING SEQUENCE OF OPERATION
Heating
The control board begins a call for heat when W is energized (con-
nected to R).
The control checks to see if the pressure switch is open. If the pressure
switch is closed, the control board flashes "2" on the LED and waits
indefinitely for it to open. When the pressure switch is sensed as open,
the control begins pressure switch proving period. If the call for heat is
removed, the control goes back to Standby.
Pressure Switch Proving
The control board energizes the induced draft motor and waits for the
pressure switch to close. When the pressure switch closes, the control
begins Pre-purge period. If the call for heat is removed, the control de-
energizes the inducer without post-purge and returns to standby.
If the pressure switch does not close within 5 seconds of inducer ener-
gizing, the control board flashes "3" on the LED. If the pressure switch
does not close within 60 seconds of inducer energizing, the control
shuts off the inducer for 60 seconds, then energizes the inducer for
another 60 seconds in an attempt to close the pressure switch. This
cycle continues indefinitely until either the pressure switch is proved
closed, or the call for heat ends.
Pre-purge
The control board monitors the pressure switch and ensures it remains
closed during pre-purge. If the pressure switch opens, the control goes
back to pressure switch proving mode. The control waits for a 15 sec-
ond pre-purge period, then begins the ignition trial.
Ignition Trial Period
The control board energizes the gas valve and spark outputs for a 5
second Ignition trial. The control de-energizes the spark when flame is
sensed and enters a flame stabilization period.
If flame is not established within the ignition trial period, the control de-
energizes the spark and gas valve and begins an inter-purge period
before attempting another ignition trial.
If the call for heat is removed during an ignition trial period, the control
immediately de-energizes spark and gas. The control runs the inducer
motor through a post purge period before de-energizing.
If the pressure switch opens during an ignition trial period, the control
immediately de-energizes spark and gas. The control begins pressure
switch proving before an inter-purge and reignition attempt.
Heat Blower On Delay
The control board waits for 30 seconds and then energizes the indoor
blower heat speed. Blower on delay time begins at the start of flame
proving period in the trial for ignition.
If the thermostat demand for heat is removed, the control de-energizes
the gas valve, energizes the blower on heat speed and initiates a post
purge and heat blower off delay.
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