PRINCIPLES OF OPERATION 5
AQUATECH OPERATIONS, SERVICE AND PARTS MANUAL
A Product of Hi-Vac Corporation
PRINCIPLES OF OPERATION
AIR PURGE PUMP PRIME & COLD WEATHER BLOWOUT SYSTEM
(Page 1 of 2)
AIR PURGE PUMP PRIME
Air Purge Pump Prime “Valve #1”
(see next page) is provided to assist the purge of air trapped
inside the suction section of the water pump. There should be sufficient head pressure from
the water in the water tanks to expell any air trapped on the suction side of the pump. Close
Air
Purge Pump Prime “Valve #1”
(see next page) when a solid water stream runs from the overflow
tube.
Air Purge Pump Prime “Valve #2”
(see next page) is provided to assist the purge of air trapped
inside the discharge section of the water pump. Any trapped air acts as a spring cushion for the
compressed water and causes the water to “bounce back” against the cushion of air. This can
cause a loud knocking noise from the pump area and severe pulsating of the sewer hose. This
is called “cavitation”. If the air is not expelled, severe damage can occur in the pump. Open the
valve to allow air trapped inside the pump to be expelled. Water will also be expelled at the
same time. Run the pump at an idle speed for several minutes until all air is expelled, then slowly
increase pump speed. As the pump develops greater pressure, the water discharged from the
valve will become very intense. When it is clear that all air has been expelled, close the
Air Purge
Pump Prime “Valve #2”
(see next page) and increase pump speed. The knocking sound should
disappear, and the pulsating of the hose will be very mild. This is normal for a triplex water pump.
At this point it is safe to operate the jetting, hydro or handgun operation. This procedure is
usually only necessary when all water has been previously purged from the system, the suction
line strainer has been removed for cleaning, or the pump has been run out of water.
Note:
If you have constant problems with cavitation, it is likely that air is being sucked into the
pump somehow, or one or more valve springs have broken. If you experience repeated cavitation,
even though the pump has not been run out of water, you should request an inspection of the
water system to determine the cause.
COLD WEATHER BLOWOUT
The Schrader Air Valve
(see next page) located on the top of the water pump, is used to purge the
pump and water piping of any trapped water and return it to the water suction line. By
connecting the purge coiled hose assembly (not shown) to the
Forced Air Disconnet
(see next
page), and the
Schrader Air Valve
, air is then introduced at the valve and water is blown back
to the water tank. The
Blowout Valve
(see next page) must be open prior to applying air to the
Schrader Air Valve
.
