©2008 Ingersoll Rand Company Page 14
modulation set point is turned on then the
modulation output is used to turn on the
modulation solenoid valves whenever the
requirements for modulation have been met.
When the compressor first starts and loads, the
modulation set point is off. If the unit cycles
(loads and unloads) 3 times in 3 minutes, the
compressor will start modulating. If the unit is
modulating, the modulation output will follow the
load output. Modulation output will be on if the
unit is loaded and off if the unit is unloaded. If
the compressor unloads and stays unloaded for
3 minutes, the compressor will stop modulating.
The compressor will have to repeat the 3 load
cycles within 3 minutes to start modulation
again. If the unit stops in auto start/stop while
modulating, it will continue modulating if it
restarts in less than 3 minutes after unloading. If
it restarts more than 3 minutes after unloading it
will have to load and unload 3 times in 3 minutes
again to start modulating. If the operator or a
fault stops the unit, the modulation output will be
off when the unit is restarted. Again, it will have
to cycle 3 times in 3 minutes for the modulation
output to be turned on.
Condensate Drain Valve (9SV) [Std] – This
120-volt coiled normally closed solenoid valve is
used to remove the condensate that has been
collected at the moisture drain with is piped into
the discharge of the aftercooler. This solenoid
valve has an output timer that toggles on for a
period defined by the Condensate Drain Time
set point. The drain valve will remain off for a