York ECO2 YPAL 050 - Manual (Page 154)

154 JOHNSON CONTROLS
FORM 100.50-NOM6 (1207)
Service
DIFFERENTIAL INPUT
PRESSURE - IWC
OUPTUT VOLTAGE - VDC
-0.50 0.00
-0.40 0.50
-0.30 1.00
-0.20 1.50
-0.10 2.00
0.00 2.50
0.10 3.00
0.20 3.50
0.30 4.00
0.40 4.50
0.50 5.00
TABLE 8-3 – BUILDING PRESSURE TRANSDUCER OUTPUT
TABLE 8-2 – DUCT PRESSURE TRANSDUCER
1.25" WC SPAN
DIFFERENTIAL
INPUT PRESS
2.5" WC SPAN
DIFFERENTIAL
INPUT PRESS
5.0" WC SPAN
DIFFERENTIAL
INPUT PRESS
VOLTAGE
VDC
0.125 0.25 0.5 0.50
0.25 0.50 1.0 1.00
0.375 0.75 1.50 1.50
0.50 1.00 2.00 2.00
0.625 1.25 2.50 2.50
0.75 1.50 3.00 3.00
0.875 1.75 3.50 3.50
1.00 2.00 4.00 4.00
1.125 2.25 4.50 4.50
1.25 2.50 5.00 5.00
Building Pressure Transducer
The Building Pressure Transducer is located behind the
right hand damper door. The purpose of the transducer is
to sense and convert the static pressure in the building to
a 0 to 5 volt DC voltage. The DC voltage is then sent to
the Unit Controller and compared against the “BUILDING
PRESSURE ACTIVE SETPOINT”. The transducer is
factory wired, but pneumatic tubing must be fi eld supplied
and installed (refer to Section 2 “INSTALLATION” in this
manual). The Building Pressure Transducer measures
differential pressure in the building and atmospheric
pressure. When verifying transducer operation, the
technician can inset a tee into the pneumatic tubing and
connect a manometer to the tee to verify the pressure being
applied to the transducer. Once this pressure is known, a
comparison can be made of the building pressure vs. output
volts DC from the transducer. A practical and quick check
of this transducer can also be accomplished by removing
the pneumatic tubing lines from both the low and high side
connections on the transducer. Since both of the inputs
will now be exposed to the same pressure, the differential
pressure will be zero, and the output 2.5 volts DC according
to Table 8-3.
Return Fan Pressure Transducer
If the unit is order with the Return Fan Option the
unit will have a Return Fan Pressure Transducer. The
transducer is behind the right hand damper door and
compares the pressure in the return air compartment to
atmospheric pressure. The Unit Controller varies the
speed of the Return Fan in order to maintain the correct
differential pressure in the return compartment. When
verifying transducer operation, the technician can inset a
tee into the pneumatic tubing and connect a manometer
to the tee to verify the pressure being applied to the
transducer. Once this pressure is known, a comparison
can be made of the return compartment pressure vs.
output volts DC from the transducer. A practical and
quick check of this transducer can also be accomplished
by removing the pneumatic tubing lines from both the
low and high side connections on the transducer. Since
both of the inputs will now be exposed to the same
pressure, the differential pressure will be zero, and the
output 2.5 volts DC according to Table 8-4.
DIFFERENTIAL INPUT
PRESSURE - IWC
OUPTUT VOLTAGE - VDC
-1.00 0.00
-0.80 0.50
-0.60 1.00
-0.40 1.50
-0.20 2.00
0.00 2.50
0.20 3.00
0.40 3.50
0.60 4.00
0.80 4.50
1.00 5.00
TABLE 8-4 – RETURN FAN PRESSURE
TRANSDUCER OUTPUT
Discharge Pressure Transducer
The discharge Pressure Transducer is located in the
common discharge line of the tandem compressors for
each refrigerant circuit. The purpose of this transducer
is to sense and convert the discharge pressure into a
DC voltage. The DC voltage is then sent to the Unit
Controller where it is used to control the number of
condenser fan when the unit is in cooling operation.
The discharge pressure value, in PSIG, is displayed by
the User Interface.