Installation
Installing Two Pumps for Tandem Operation
23
Installing Two Pumps for Tandem Operation
When greater flow rates are needed, two pumps may be required in the same piping system by means of a
manifold. If they are installed according to the illustration, a tandem system offers backup support so operations
can continue if one pump stops working. Install the pump as outlined above with the following additions.
1.
If a siphon system is required, each pump must have 3/8 inch siphon vacuum line attached to the same
location on the siphon line (reference Figure 11).
Adjust the Pressurstat (see “Adjusting the Pressurstat Line Relief Pressure” on
page 28) on both packers to maximum relief pressure by rotating fully clockwise. If
maximum pump pressures are NOT a minimum of 5 psi below the Pressurstat relief
setting then proper check valves with pressure relief are required to be installed in the
discharge line of each pump to prevent product from being pumped through the pres-
sure relief system of the adjacent pump when it is not operating. Readjust the Pres-
surstat to the desired pressure relief value for proper operation of the siphon system.
Installation of a ball valve is recommended on the discharge side of the pressure relief check
valve. This will aid in troubleshooting and line testing.
Figure 12 illustrates the requirement for in-line, pressure relief type check valves. It is not a
recommended guide for installation of piping downstream of the check valves.
Figure 12.
WARNING
NOTICE
rj/051-301-14.eps
As an option, install ball
valves downstream for
trouble shooting and
maintenance
The check valves shown installed in
the discharge line of each pump are
necessary to prevent product from
being pumped through the pressure
relief system of the adjacent pump, if
that pump is not running. This is
because the expansion relief valve
operates at below pump pressures. If
check valves without pressure relief
were used, there would be no
provision for thermal expansion
between the valves and the
dispensers.
WARNING
