SGNe Troubleshooting Guide Page 24
Revision 1.0; Davidson, May 2009. ©Ingersoll Rand Proprietary Information
SGNe
Troubleshooting Guide
Danger
Please utilize extreme caution when performing work within the compressor cabinet.
When opening the cabinet: be certain to wear appropriate PPE (Personal Protective Equipment),
follow lock out-tag out procedures, and ensure all safety procedures are followed
.
Condensate Solenoid Control
The condensate solenoid will be used to remove condensation from the compressor. When
the compressor is running, the condensate solenoid will open on a timed interval. The
condensate solenoid will remain open for the number of seconds in the condensate release
set point and then close. The condensate solenoid will also open 10 seconds after the
compressor starts for the condensate release time.
PDM Fan
The PDM fan will run anytime the compressor is running. Once the compressor stops, the
PDM fan will continue to run for 2 minutes.
Warm Up Operation
A warm up cycle occurs when the compressors airend discharge temperature doesn’t reach
the warm up temperature set point for two consecutive operational cycles. On a warm up
cycle, instead of stopping, the compressor will continue to run with the blowdown valve open.
The compressor will run in a fixed speed mode, at minimum speed. The blower will
operate at
minimum speed. The compressor will run like this for the time period selected in
warm up time.
If the pressure falls during this time period, the compressor will return to normal operation.
Remote Pressure Sensor Operation
If the unit is equipped with the remote sensor option, the VSD will use the remote sensor to
control the speed of the compressor. The package discharge pressure sensor will still be used
for determining an immediate stop. However, the remote pressure sensor will be compared to
the target and auto stop pressure values.
The problem with the remote sensor option is that the remote pressure value is normally a
t a
lower pressure than the package discharge pressure. This can cause the compressor t
o use
too much power because the maximum speed of the compressor is set by the targe
t pressure.
The problem is that the maximum speed is based on the package discharge pressure. If the
compressor is operating at full speed and the package discharge pressure i
s above the target
pressure, the compressor will be high on power usage.
To compensate for this, the Intellisy
s will measure the difference between the package discharge
pressure and the remote pressure
. New minimum and maximum speeds will then be sent to the
VSD that are based on the targe
t pressure plus the pressure differential.
For example, if th
e target pressure is 100 Psi, the remote pressure sensor reading is 98 Psi, and
the packag
e discharge pressure reading is 106 Psi, the Intellisys will calculate a pressure
differential of 8 Psi
. The unit will still try to maintain a remote pressure of 100 Psi, however the
Intellisys will send th
e 108 Psi (target pressure + pressure differential) minimum and maximum
speeds to the VSD
.
If the compressor is stopped or if the package discharge pressure falls 3 psi below the target
pressure, the Intellisys will reset the minimum and maximum speeds to the original values
(those associated with the actual target pressure). Also, if the pressure differentia
l between the
package discharge pressure and the remote pressure increases by 2 psi o
r decreases by 3 psi,
the Intellisys will calculate a new differential pressure and send new minimu
m and maximum
speeds to the VSD, based on the new pressure differential.
To Next Page
Loading...
