York YCAL0012EC, Installation Operation & Maintenance

Page: 150 / 166

JOHNSON CONTROLS
150
FORM 150.66-NM2
ISSUE DATE: 09/25/2020
SECTION 9 - SERVICE AND TROUBlEShOOTING
The suction transducers have a range from 0 psig to
400 psig (27.58 barg). The output will be linear from
0.5 VDC to 4.5 VDC over the 400 psig (27.58 barg)
range. Following is a formula that can be used to verify
the voltage output of the transducer. All voltage readings
are in reference to ground (unit case).
V = (Pressure in psig x 0.01) + .5
or
V = (Pressure in BARG x 0.145) + .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
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.
J7-9 = +5VDC return
J7-1 = drain (shield connection = 0VDC)
Digital Outputs
Refer to the unit wiring diagram and Fig. 28. The digital
outputs are located on TB7, TB8, TB9 and TB10 of the
microboard. ALL OUTPUTS ARE 120VAC with the
exception of TB8-6 to TB8-7 which are the contacts that
can be used for a remote 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 I/O board via connections at
TB7-1, TB7-6, TB8-1, and TB9-1. Fig. 28 illustrates the
relay contact architecture on the microboard.
FIG. 28 – I/O BOARD RELAY CONTACT
ARCHITECTURE
lD13277
SYS 1
COMP 1
TB7-2
SYS 1
COMP 2
TB7-4
SYS 1
COMP 3
TB7-5
TB7-3 LLSV 1
TB7
TB7
SYS 1
HGSV
TB7-7
SYS 1
FAN 1
TB7-9
SYS 1
FAN 3
TB7-10
TB7-8
SYS 1
FAN 2
TB8-6
EVAP
PUMP
TB8-7
TB8
TB8-2
HEAT EXCH
HEATER