Gorman-Rupp Pumps RD2A31-BAR All serial numbers - Manual (Page 17)

OM-03989 RS AND RD SERIES PUMPS
PAGE C - 3 OPERATION
tral position. If it does not, flush the group grind
with penetrating oil, and check the slide travel
again. The slide should move freely. Reinstall the
pressure regulating spring and spring cap, and
clean and reinstall the drain plug.
Air Release Valve (“BAR” Models)
When properly installed, the Air Release Valve al­
lows the integral Roto‐Prime
T priming pump to
overcome relatively high static discharge heads or
back pressure during the priming cycle. Figure 1
shows a schematic configuration of the valve and
is keyed to the following description of operation.
DISCHARGE LINE CHECK
VALVE (MANDATORY)
VENT TO OUTSIDE IF INSTALLED IN
PUMP HOUSE (CHECK VALVE REQUIRED
ON DUPLEX INSTALLATION ONLY)
DISCHARGE
SUCTION
AIR RELEASE
VALVE
GORMAN‐RUPP ROTO‐PRIME
T
SELF‐PRIMING CENTRIFUGAL PUMP
A
B
C
D
E
Figure 1. Gorman-Rupp Air Release Valve Connected To Roto-Prime
T Pump
The Air Release Valve is designed with an air valve
in the head of the assembly and a sump valve in the
base of the assembly. These valves are controlled
by a common rod which is moved vertically by an
attached float.
When the pump is first installed, there is air in the
suction line, the Air Release Valve is open, and
there is back pressure against the discharge line
check valve “D”.
When the pump is started, air is drawn from the
suction line into the priming pump through the
priming tube “A”, compressed by the priming
pump, and discharged through the discharge tube
“B” to the Air Release Valve. This air and vapor is
then vented to the atmosphere through the valve
head.
With the float down, sump valve “E” is closed; air
cannot re‐enter the suction piping through the re­
turn tube assembly “C”.
As product fills the pump casing, the impeller de­
velops pressure, opening check valve “D” in the
discharge piping. The priming pump will deliver
product, filling the float chamber. The float will rise,
opening sump valve “E”, and closing the air valve.