Johnson Controls York YCAL0014E Series, Installation, Operation & Maintenance Instructions Manual

Page: 122 / 216

JOHNSON CONTROLS
122
FORM 150.62-NM6 (103)
FIG. 14 – MICRObOARD RELAY CONTACT
ARCHITECTURE
LD03842
The suction transducers have a range from 0 to 200
PSIG (13.79 bARG). The output will be linear from
.5VDC to 4.5VDC over the 200 PSIG (13.79 bARG)
range. Following is a formula that can be used to verify
the voltage output of the transducer. All voltage reading
are in reference to ground (unit case).
V = (Pressure in PSIG x .02) + .5
or
V = (Pressure in bARG x .29) + .5
where V = dc voltage input to micro
Pressure = pressure sensed by transducer
Following are the microboard connections for the Suc-
tion Transducer:
System 1 Suction Transducer
J4-5 = +5VDC regulated supply to transducer.
J4-10 = VDC input signal to the microboard.
See the formula above for voltage readings
that correspond to specific suction pressures.
J4-1 = +5VDC return
J4-2 = drain (shield connection = 0VDC)
System 2 Suction Transducer
J7-5 = +5VDC regulated supply to transducer.
J7-10 = VDC input signal to the microboard.
See the formula above for voltage readings
that correspond to specific suction pressures.
J7-1 = +5VDC return
J7-2 = drain (shield connection = 0VDC)
If the optional Suction Transducer is not used on the
YCAL0014 - YCAL0060, a Low Pressure switch will be
used. Following are the microboard connections for the
Low Pressure switch.
System 1 Low Pressure Switch
J4-5 = +5VDC regulated supply to LP switch.
J4-10 = input signal to the microboard. 0VDC =
open switch / +5VDC = closed switch.
J4-2 = drain (shield connection = 0VDC)
System 2 Low Pressure Switch
J7-5 = +5VDC regulated supply to LP switch.
J7-10 = input signal to the microboard. 0VDC = open
switch / +5VDC = closed switch.
J7-2 = drain (shield connection = 0VDC)
Service and Troubleshooting
DIGITAL OUTPUTS
Refer to the unit wiring diagram and Fig. 14 and Table
35. The digital outputs are located on Tb3, Tb4, and Tb5
of the microboard.
ALL OUTPUTS ARE 120vAC with
the exception of Tb5-3 to Tb5-4. Tb5-3 to Tb5-4 are the
contacts that can be used for an evaporator pump start
signal. The voltage applied to either of these terminals
would be determined by field wiring.
Each output is controlled by the microprocessor by
switching 120VAC to the respective output connection
energizing contactors, evaporator heater, and solenoids
according to the operating sequence.
120VAC is supplied to the microboard via connections
at Tb3-1, Tb3-7, Tb4-3, and Tb4-7. Figure 14 illustrates
the relay contact architecture on the microboard.