Universal Pump Service Manual
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Universal XR Pump Functional Components
The Universal XR Pump systems consists of fi ve basic assemblies:
Pump Stack Assembly
The pump stack contains two silicone diaphragms driven by a DC motor and low-pressure positive-acting valves. The
pump mechanism is sealed to protect it from dust. The motor operates from a rechargeable Nickel Cadmium (NiCad)
ba! ery. The stack consists of two halves. The top half contains the pulsation dampener and pressure regulator. The
bo! om half holds the pump and motor.
Pulsation Dampener Assembly
The pulsation dampener assembly maintains a pulsation-free fl ow. This assembly consists of a pair of diaphragms and
is located directly below the regulator assembly (Figure 2, #2). There are two dampeners in each universal pump.
Regulator Assembly
The regulator assembly is used for low fl ow sampling in the 5 to 500 ml/min fl ow range (Figure 2, #1). The assembly
consists of a sensing diaphragm with a pre-loaded spring that automatically opens or closes an air inlet valve to recycle
the air within the pump to maintain 20 inches of water across a control restrictor. The regulator is not used in high fl ow
applications above 500 ml/min.
A manual valve located below the small round protective cap screw on top of the pump (Figure 1, #14) can be opened
to activate the regulator. The regulator can be controlled by turning the screw under the cap screw (clockwise closes it,
counterclockwise opens it).
The regulator is factory preset at 20 inches water back pressure and should not be adjusted for normal use.
Flowmeter Assembly
This rotameter-style fl owmeter is mounted vertically in the case and is used to monitor pump fl ow (Figure 1, #13). While
rotameters are very repeatable, they are not high-precision instruments and should be verifi ed to a primary standard
fl owmeter.
Filter Assembly
The pump inlet consists of a see-through housing and a fi lter membrane held in place by an O-ring (Figure 1, #9, 10 , 11,
and 12). All incoming air passes through the fi lter assembly. The transparent housing permits the user to determine if
the pump fi lter needs to be changed.
A clogged fi lter can aff ect back pressure and reduce ba# ery run time.
Universal XR Sample Pump Operational Components
The on/off switch (Figure 1, #4), keypad, and fl ow adjust potentiometer (pot) (Figure 1, #7) is under the anti-tamper
keypad cover. Use a fl at-head screwdriver to remove the anti-tamper cover (Figure 1, #5).
On/Off Switch
Use a ballpoint pen or small screwdriver to slide the switch up and turn on the pump.
Keypad
Each model has diff erent features, therefore, the keypad bu# ons on each are diff erent. The 44XR model does not have
a keypad. The keypad functions and features indicated below are for the PCXR8 model only. For more detailed information
about pump operation, see the pump operating instructions.
