Instruments; Air Control Components; Oil Level Gauge; Inlet Valve - Gardner Denver Electra-Screw EDEQHF Operating And Service Manual

AIR FILTER
VACWN WITCH
BLOVWII ORIFICE
FACU
lNLEF VALVE
(OPEN
F.)5ITIou)
BLOUWHN VALVE
PLUG
FIGURE 4-2- INLET VALVE
in the final discharge line and set at the factory to
approximately 120%.
of the unit's full load operating
pressure for protection against overpressure. Periodic
checks should be made to insure its proper operation.
The relief valve should be tested for proper operation at
least once every year. To test relief valve, raise system
operating pressure to 75% of the relief valve set pressure
and manually open the valve with the hand lever. Hold
valve open for a few seconds and allow it to snap shut.
I
wARNING
I
cAuTION
When relief valve opens, a stream of
high velocity air is released, resulting
in a high noise level and possible dis-
charge of accumulated dirt or other
debris. Always wear eye and ear pro-
tection and stand clear of the dis-
charge port when testing the relief
valve to prevent injury.
Never paint, lubricate or alter a relief
valve. Do not plug vent or restrict dis-
charge.
1
wARNING _
Operation of unit with improper relief
valve setting can result in severe per-
sonal injury or machine damage.
Insure properly set valves are installed
and maintained.
IN
OUT
FIGURE 4-3- MINIMUM PRESSURE/CHECK VALVE
Blowdown Valve (Figure
4-1, page 1, this section) - The
blowdown valve releases pressure from the oil reservoir.
See description under''Air Control Components," below,
for construction and operation information.
INSTRUMENTS - All units incorporate the following
instruments and indicators:
Oil Level Gauge (Figure 1-3, page 3, Section 1) - The
oil level gauge is located on the side of the reservoir.
See Section 5, "Lubrication, Oil Cooler, Oil Filter and
Separator", for information on how to correctly read the
gauge. All other instruments are part of the programma-
ble controller.
AIR CONTROL COMPONENTS - All
units incorporate
the following air control components. See Figure 1-4 for
schematic tubing diagram.
Inlet Valve (Figure 4-2, above) - The inlet valve is a
pilot-actuated valve that restricts the inlet to control
capacity and closes to unload the compressor. At shut-
down the inlet valve closes to function as a check valve
and prevent backflow of air.
As control pressure is increased the valve will begin to
close, restricting the inlet and reducing compressor
capacity. Approximately 18 psig of control pressure is
required to close the inlet valve completely. When
closed, the inlet valve prevents the flow of air in either
direction.
With optional modulating control feature:
when the control pressure is less than
18
psig, the inlet
valve will modulate to match compressor capacity to
system demand.
Blowdown Valve (Figure
1-2,
page 2, Section 1) - The
blowdown valve is atwo-way solenoid valve that is piped
into the oil separator outlet, but ahead of the check valve.
When the solenoid is de-energized, the blowdown valve
opens, and the oil system is blown down. When the
solenoid is energized, the blowdown valve closes, and
allows the oil system to pressurize.
13-8-610 Section 4 Page 2