Anti-Recycle Timer; Anti-Coincidence Timer; Evaporator Pump Control And York Hydro Kit Pump Control; Evaporator Heater Control - York YCAL0019 Installation Operation & Maintenance

FORM 150.67-NM2
ISSUE DATE: 01/31/2019

ANTI-RECYCLE TIMER

The programmable anti-recycle timer assures that
systems do not cycle. This timer is programmable un-
der the PROGRAM key between 300 – 600 seconds.
Whenever possible, to reduce cycling and motor heat-
ing, the anti-recycle timer should be adjusted to 600
seconds. The programmable anti-recycle timer starts
the timer when the first compressor in a system starts.
The timer begins to count down. If all of the compres-
sors in a circuit cycle off, a compressor within the cir-
cuit will not be permitted to start until the anti-recycle
timer has timed out. If the lead system has run for less
than 5 minutes, 3 times in a row, the anti-recycle timer
will be extended to 10 minutes.

ANTI-COINCIDENCE TIMER

This timer is not present on single-system units. Two
timing controls are present in software to assure com-
pressors within a circuit or between systems, do not
start simultaneously. The anti-coincidence timer as-
sures there is at least a one minute delay between sys-
tem starts on 2-circuit systems. This timer is NOT pro-
grammable. The load timers further assure that there
is a minimum time between compressor starts within
a system.
EVAPORATOR PUMP CONTROL AND YORK
HYDRO KIT PUMP CONTROL
The evaporator pump dry contacts (CTB2 – terminals
23 – 24) are energized when any of the following con-
ditions are true:
1. Low Leaving Chilled Liquid Fault
2. Any compressor is running
3. Daily Schedule is ON, Unit Switch is ON and Re-
mote Stop is closed.
The pump will not run if the micro panel has been pow-
ered up for less than 30 seconds or if the pump has run
in the last 30 seconds to prevent pump motor overheat-
ing.
Whenever the option "YORK HYDRO KIT PUMPS =
1" is selected under the OPTIONS key, the pump con-
trol will be as described above. DO NOT SELECT the
option "YORK HYDRO KIT PUMPS = 2" under the
OPTIONS key. If a dual pump option is installed, the
active pump is selected by the selector switch.
JOHNSON CONTROLS

EVAPORATOR HEATER CONTROL

The evaporator heater is controlled by ambient air tem-
perature. When the ambient temperature drops below
40 °F (4.4 °C) the heater is turned on. When the tem-
perature rises above 45 °F (7.2 °C) the heater is turned
off. An under voltage condition will keep the heater off
until full voltage is restored to the system.

PUMPDOWN CONTROL

Each system has a pump-down feature upon shut-off.
Manual pumpdown from the keypad is not possible.
On a non-safety, non-unit switch shutdown, all com-
pressors but one in the system will be shut off. The
LLSV will also be turned off. The final compressor
will be allowed to run until the suction pressure falls
below the cutout, or for 180 seconds, whichever comes
first.

STANDARD CONDENSER FAN CONTROL

Condenser fan operation must be programmed with the
Options key under "Fan Control." Condenser fan con-
trol can be selected for Ambient Temp. and Discharge
Pressure, or Discharge Pressure only.
The condenser fan control by "Ambient Temperature
and Discharge Pressure" is a feature that is integral to
the standard software control. If the optional discharge
transducer is not installed, the condenser fans will op-
erate based on outdoor ambient temperature only. Re-
fer to the following pages for model specific details.
The condenser fan control by "Discharge Pressure" is
a feature that can be selected if the discharge pressure
transducer is installed and fan cycling is not a concern.
Fan control by discharge pressure will work according
to the tables on the following pages. The fan control
on-pressure and fan differential off-pressure are pro-
grammable under the PROGRAM key.
The delay between turning on and off fan stages is al-
ways fixed at 5 seconds.
When a fan stage is turned on by pressure, the on
pressure for the next stage is increased 20 PSIG and
ramped back to the programmed on pressure over the
next 20 seconds. Typically, standard ambient control
ON pressure should be programmed at 385 PSIG with
a differential of 125 PSIG.
SECTION 8 – UNIT OPERATION
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