Johnson Controls York YCRL0064, Installation Operation & Maintenance

Page: 143 / 162

JOHNSON CONTROLS
143
SECTION 9 – SERVICE AND TROUBLESHOOTING
FORM 150.27-NM1
ISSUE DATE: 09/30/2015
9
The suction transducers have a range from 0 to 400
PSIG (27.5 barg). The output will be linear from
0.5VDC to 4.5VDC over the 400 PSIG (27.5 barg)
range. Following is a formula that can be used to verify
the voltage output of the transducer. All voltage read-
ing 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 microprocessor
Pressure = pressure sensed by transducer
Following are the I/O board 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)
System 2 Suction Transducer
J9-5 = +5VDC regulated supply to transducer.
J9-10 = VDC input signal to the microboard.
See the formula above for voltage readings
wthat correspond to specific suction pressures.
J7-9 = +5VDC return
J7-11 = drain (shield connection = 0VDC)
Digital Outputs
Refer to the unit wiring diagram and
Figure 38 on page
143 . The digital outputs are located on TB7, TB8, and
TB9 and TB-10 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 evapora-
tor 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 ( see Figure 38 on
page 143 ).
120VAC is supplied to the I/O board via connections
at TB7-1, TB7-6, TB10-1, TB10-6, TB8-1 and TB9-1.
Figure 38 on page 143 illustrates the relay contact
architecture on the microboard.
FIGURE 38 - I/O BOARD RELAY CONTACT
ARCHITECTURE
LD12722A
SYS 1
COMP 1
TB7-2
SYS 1
COMP 2
TB7-4
SYS 1
COMP 3
TB7-5
TB7-3 LLSV 1
TB8-6
EVAP
PUMP
TB8-7
TB7
SYS 2
HGSV
TB10-7
TB10-8
TB10-9
TB10-10
TB10
TB8
TB10
SYS 2
COMPR 1 (4)
TB10-2
LLSV 2 TB10-3
SYS 2
COMPR 2 (5)
TB10-4
SYS 2
COMPR 3 (6)
TB10-5
TB7
TB7-7
TB7-9
TB7-10
TB7-8
TB8-2
HEAT EXCH
HEATER