Trebor 620R Magnum - Manual (Page 5)

MAGNUM 620R PUMP OPERATION / MAINTENANCE MANUAL PAGE 5
1.3 CHECK MUFFLER OPERATION
1.3.a Purpose
NOTE: The check muffler is not designed to control pump speed. Use of the
check muffler for this purpose could result in serious damage to the pump.

Permits pump to operate reliably in systems that incorporate a discharge flow
less than 3 gpm.

Permits pump to operate reliably in systems that have the pump located at
an elevation below the liquid supply level and flows below 3 gpm. (Pump air
supply remains on.)

Effectively reduces the amount of harmful acid vapors that can enter into the
pump’s internal air circuit components while the pump air supply is off.
1.3.b Adjustment
The check muffler has 3 preset arrangements. The pump is shipped from the
factory in the medium back pressure setting, see Mid-Setting in Figure 1-2:
Check Muffler.
Mid-Setting

Start pressure <15 psi

Low flow applications (flow <3 gpm)

The Check Muffler is preset at the factory at the mid-setting. This setting
protects the pump air system from caustic fumes and allows the pump to
maintain a “Dead Head” condition with supply pressures up to 35 psi. This
setting also protects the pump in conditions of positive inlet supplies up to 10
ft. above the inlet of the pump.
High-Setting

Start pressure at <30 psi

Air supply >40 psi, low flow application (flow <3 gpm)

By removing the muffler from the pump and reversing the spring assembly in
the muffler then reinstalling the muffler, the Check Muffler is now set in the
highest back pressure setting. This setting protects the pump from dead
head conditions up to 60 psi, or from positive inlet heads up to 20 ft.
However, this setting is not recommended for operating fluid temperatures
over 60

C as damage to the pump shaft can occur. This setting also
diminishes the pump’s flow capacity by 15% from normal published curves.
This setting also increases the pump start pressure from 15 psi to
approximately 30 psi.
Low-Setting (no picture shown)

Spring assembly removed

Start pressure <10 psi

Low back pressure, high flow (>3 gpm) requirement