Gorman-Rupp Pumps VS6A60-B 1321070 thru 1352520 - Manual (Page 13)

OM-06014 ULTRA V SERIES
PAGE B - 6 INSTALLATION
Air Release Valve Installation
Staged pump applications generate much higher
operating pressures within the pump casings than
non‐staged pump applications. This high pressure
could cause a suction check valve to fail, resulting
in loss of prime. Therefore, any pump used in a
staged application, whether in the lower or up­
per position, must have the suction check valve
removed. The lower stage of the VS Series pump
is designed without a suction check valve, so re­
moval of the check valve is not required.
In order to maintain the suction leg and facilitate ini­
tial priming (or re‐priming if the suction leg is lost)
without a suction check valve, it is recommended
that staged pump applications be installed using
two discharge check valves, with an automatic Air
Release Valve installed between the two discharge
check valves (see Figure 3). In this manner, when
the liquid level in the sump activates the automatic
liquid level device and starts the pumps, discharge
pressure opens the first discharge check valve, al­
lowing any entrained air in the system to escape
through the Air Release Valve. When air in the sys­
tem is purged, pressure opens the second dis­
charge check valve for full operation.
When the liquid level in the sump lowers enough to
de‐activate the automatic liquid level device and
stop the pumps, the first discharge check valve
closes and creates an air‐tight seal, thus maintain­
ing liquid in the pump casing and suction line to al­
low the pump to re‐prime when the liquid level in
the sump rises and again activates the automatic
liquid level device.
The second discharge check valve in the staged
application acts as a “shock absorber” to prevent
destructive “water hammer” when the pump shuts
down.
The Automatic Air Release Valve must be inde­
pendently mounted in a horizontal position be­
tween the discharge check valves. (see Figure 2).
The inlet opening in the Air Release Valve is
equipped with standard 1‐inch NPT pipe threads.
DISCHARGE
CHECK
VALVE
AIR RELEASE
VALVE
DISCHARGE
PIPE
DISCHARGE
CHECK
VALVE
VS SERIES PUMP
Figure 2. Typical Automatic Air Release Valve Installation
NOTE
When installing the Air Release Valve on a staged
pump application, position the Air Release Valve as
close as possible to the primary discharge check
valve. Six‐inch and larger discharge check valves
are available drilled and tapped to receive a stan­