49
4
Hardware Details
4.1
Programmable Controller
The programmable controller is preprogrammed by Desert Aire for the control of your
unit. The Desert Aire replacement part number for both of these controllers is available
by calling our service department.
4.2
Suction Pressure Transducer
The Suction Pressure Transducer is a 0.5-4.5 VDC to 0-250 psig ratio metric device.
The body is brass with a 1/4 SAE female refrigerant connection. This transducer must
be supplied with 4.5 to 5.5 VDC power. A display reading of 0.0 psig for the transducer
indicates the device is disconnected or defective. For this device to function, 5.0 VDC
must be present from the black to green wires on the transducer. To verify the output
of the transducer, measure the DC voltage (should read between 0.5 to 4.5 VDC) from
the white to green wires on the transducer and use this voltage in the following formula
to determine the pressure (0-250 psig).
Pressure (psig) = (62.5) * (V) – 31.25
Example, if V = 2.50 VDC, then;
Pressure (psig) = (62.5) * (2.50) – 31.25
= 156.25 – 31.25
= 125 psig
The Suction Pressure Transducer’s replacement part number is available from Desert
Aire by calling our service department.
4.3
Discharge and Liquid Pressure Transducer
The Discharge & Liquid Pressure Transducers are 0.5-4.5 VDC to 0-652 psig ratio
metric devices. The body is brass with a 1/4 SAE female refrigerant connection. This
transducer must be supplied with 4.5 to 5.5 VDC power. A display reading of 0.0 psig
for the transducer indicates the device is disconnected or defective. For this device to
function, 5.0 VDC must be present from the black to green wires on the transducer. To
verify the output of the transducer, measure the DC voltage (should read between 0.5
to 4.5 VDC) from the white to green wires on the transducer and use this voltage in the
following formula to determine the pressure (0-652 psig).
Pressure (psig) = (163) * (V) – 81.5
Example, if V = 2.50 VDC, then;
Pressure (psig) = (163) * (2.50) – 81.5
= 407.5 – 81.5
= 326 psig
Desert Aire - CM3550 Manual
Summary of Contents for CM3550 Series
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Page 5: ...5 Desert Aire CM3550 Manual Product Warning for the State of California ...
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Page 34: ...34 Figure 47 Figure 48 Figure 49 Figure 50 Desert Aire CM3550 Manual ...
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