Gasboy 70 Series - Manual (Page 17)

Installation
MDE-4423B Series 70 and 1800 Consumer Elect Pumps Installation/Operation/Parts
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July 2005 2-9
Vacuum Breaker
The vacuum breaker tubing kit can be used with any Series 70 or 1820 pump. The vacuum
breaker is used to break a siphon should the nozzle drop below the fluid level in the tank while the
pump is stuck in the open position. A threaded vacuum breaker, P/N 066570 is shipped installed
in the pump. GASBOY Requires that the vacuum breaker be tubed back to the tank using UL
Listed fittings.
The illustration below shows two methods for installing tubing for the vacuum breaker. In all
instances, the vacuum breaker must be tubed (using 1/4-inch tubing) to the vapor space at the top
of the tank; if the tube is installed below the fluid level of the tank, the ability to break vacuum and
prevent siphoning will be lost. Using the illustrated methods, the tube end may terminate into the
annular vapor space between the 1-inch suction pipe and the 2-inch mounting pipe, or into an
opening in the top of the tank. All components shown are provided when you order the kit, P/N
032700.
NOTE:
Tubing can be piped to any available opening on top of tank. Use reducer bushings
as required.
The illustration on the next page shows vacuum breaker tubing for installations where the pump is
installed below the fluid level of the tank. For these installations, the tubing must run directly to
the tank top. The tubing must be horizontal or must slope either toward the pump or the tank so
there are no traps or low spots. Traps or low spots can severely affect vacuum breaker
performance. Tubing length should not exceed eight feet.