SKC 224-44XR User manual

Universal Pump
Cat. Nos. 224-44XR, 224-PCXR4, and 224-PCXR8
Service Manual
SKC Inc.
863 Valley View Road
Eighty Four, PA 15330-8619
Publication #1377 Rev 0910

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Table of Contents
Introduction.................................................................................................................................................................... 1
Performance Profile ...................................................................................................................................................... 1
Universal XR Sample Pump Functional Components ............................................................................................... 3
Pump Stack Assembly........................................................................................................................................... 3
Pulsation Dampener Assembly.............................................................................................................................. 3
Regulator Assembly .............................................................................................................................................. 3
Flowmeter Assembly ............................................................................................................................................. 3
Filter Assembly ...................................................................................................................................................... 3
Universal XR Sample Pump Operational Components.............................................................................................. 3
On/Off Switch......................................................................................................................................................... 3
Keypad................................................................................................................................................................... 3
LCD........................................................................................................................................................................ 4
Flow Adjust Potentiometer (pot) ............................................................................................................................ 4
Universal XR Sample Pump Electrical System........................................................................................................... 4
Battery Pack .......................................................................................................................................................... 4
Keypad and LCD ................................................................................................................................................... 4
Motor Control Circuitry........................................................................................................................................... 4
Functional Testing......................................................................................................................................................... 5
Initial Leak Check .................................................................................................................................................. 5
Pump Flow Rate Spot Check................................................................................................................................. 5
Testing Flow Range Compensation....................................................................................................................... 6
Testing the Pressure Regulator ............................................................................................................................. 6
Pump Disassembly........................................................................................................................................................ 7
Removing the Battery Pack ................................................................................................................................... 7
Removing the Back Pump Case............................................................................................................................ 7
Locating and Correcting Leaks .............................................................................................................................. 7
Checking Pumping Operation................................................................................................................................ 8
Setting the Regulator ............................................................................................................................................. 8
Disassembling the Stack ....................................................................................................................................... 9
Checking the Motor.............................................................................................................................................. 10
Disassembling the Filter Housing ........................................................................................................................ 10
Removing the Control Board and Keypad ........................................................................................................... 10
Pump Reassembly....................................................................................................................................................... 11
Reassembling and Replacing the Stack .............................................................................................................. 11
Setting the Flow Compensation........................................................................................................................... 12
Replacing the Back Pump Case .......................................................................................................................... 13
Reassembling and Replacing the Filter Housing................................................................................................. 13
Replacing the Battery Pack ................................................................................................................................. 13
Troubleshooting .......................................................................................................................................................... 14
Figures..................................................................................................................................................................... 16-24
Addenda ....................................................................................................................................................................... 25
Indicates a caution or warning.

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Introduction
Universal XR Sample Pumps
Universal XR Sample Pumps are pneumatic constant flow samplers that contain a fully electronic system built for
a broad range of applications. Flow is compensated to within ± 5% accuracy over the full range of flows and back
pressure.
There are three Universal XR pump models:
224-44XR No additional features
224-PCXR4 LCD and 2-buon keypad for built-in timer and flow fault/baery check
224-PCXR8 LCD and 6-buon keypad for programming delayed start time, automatic shutdown
time, and intermient sampling plus flow fault/baery check
Models 44XR, PCXR4, and PCXR8 are RFI/EMI-shielded and UL Listed for intrinsic safety.
Performance Profile
Operating Range: 1000 to 5000 ml/min (5 to 500 ml/min requires adjustable low flow holder)
Weight: 34 oz (964 gm)
Dimensions: 5.1 x 4.7 x 1.9 inches; (13 x 11.9 x 4.8 cm)
Compensation
Range:
1000 ml/min up to 40 inches water back pressure
2000 ml/min up to 40 inches water back pressure
2500 ml/min up to 40 inches water back pressure
3000 ml/min up to 35 inches water back pressure
4000 ml/min up to 20 inches water back pressure
5000 ml/min up to 10 inches water back pressure
Flow Control: Holds constant flow to ± 5% of the set point
Run Time: 8 hrs minimum at 4000 ml/min and 20 in water back pressure, dependent on media used
Flow Indicator: Built-in rotameter with 250 ml division; scale marked at 1, 2, 3, 4, and 5 L/min
Power Supply:
Charging Time:
(with SKC approved charger)
Plug-in baery pack, rechargeable NiCad 2.0-Ah capacity, 6.0 V, UL Listed
6 to 8.5 hrs with PowerFlex Charger
Operating Temp: 32 to 113 F (0 to 45 C)
Storage Temp: -40 to 113 F (-40 to 45 C)
Charging Temp: 50 to 113 F (10 to 45 C)
Operating Humidity: 0 to 95% non-condensing
Multiple Sampling: Built-in constant pressure regulator allows user to take up to four simultaneous samples
at different flow rates up to 500 ml/min each using optional adjustable low flow holder.
RFI-shielding
Performance:
Complies with requirements of EN 55022, FCC Part 15 Class B, EN 50082-1; frequency
range of the radiated susceptibility test was 27 MHz to 1000 MHz, CE marked.
Intrinsic Safety: UL Listed for: Class I, Division 1 and 2, Groups A, B, C, D; Class II, Division 1 and 2,
Groups E, F, G; and Class III, Temp Code T3C.

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Performance Profile (cont.)
Use only SKC-approved parts to ensure reliable performance. Failure to do so voids UL Listing for
intrinsic safety and any warranty.
These additional features are found on the PCXR4 and the PCXR8
Flow and Low Ba!ery Fault: Fault shutdown at excessive back pressure or low baery with LCD indicator and time display
retention.
Ba!ery Test: LCD shows baery condition prior to sampling.
Time Display: LCD shows sampler run time in minutes for sampler period elapsed time, pump run-time or
total elapsed time including delayed start time.
Timing Accuracy: ± 0.05% (± 45 seconds/day)
Sampling Pause: Allows user to temporarily halt sampling without loss of timing data. Restart does not require
reseing time.
These additional features are found on the PCXR8
Timed Shutdown: Allows user to select minutes of operation before automatic shutdown.
Delay On: Allows user to select minutes to delay of test up to 9999 minutes (7 days).
Intermi!ent
Sampling:
Programmable to allow user to extend short term samples over an extended period of time to
meet Time Weighted Average (TWA) requirements with a reduced number of samples. Elapsed
time maximum is 9999 minutes (7 days).

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Universal XR Pump Functional Components
The Universal XR Pump systems consists of five 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 flow. 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 flow sampling in the 5 to 500 ml/min flow 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 flow
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 flowmeter is mounted vertically in the case and is used to monitor pump flow (Figure 1, #13). While
rotameters are very repeatable, they are not high-precision instruments and should be verified to a primary standard
flowmeter.
Filter Assembly
The pump inlet consists of a see-through housing and a filter membrane held in place by an O-ring (Figure 1, #9, 10 , 11,
and 12). All incoming air passes through the filter assembly. The transparent housing permits the user to determine if
the pump filter needs to be changed.
A clogged filter can affect back pressure and reduce ba#ery run time.
Universal XR Sample Pump Operational Components
The on/off switch (Figure 1, #4), keypad, and flow adjust potentiometer (pot) (Figure 1, #7) is under the anti-tamper
keypad cover. Use a flat-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 different features, therefore, the keypad bu#ons on each are different. 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.

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Start/Hold - toggles between Start and Hold
Flow and Ba!ery Check - sets flow without affecting elapsed time and displays ba#ery status.
• Bat OK displays if just off the charger
• Bat displays if the pump can be run
• Bat Lo displays if the pump cannot sustain itself
Set-up - sets a delayed start, pump period, and sample period.
Mode - steps across delayed start, sample period, and pump period modes once the pump is in setup.
Digit Select - steps across to le$ to set next time digit (keep pressing to return to original position).
Total Elapsed Time (in minutes) - press and hold bu#on for display on LCD.
Digit Set - allows user to enter time to start. Keep pressing until desired number appears (0 to 9).
Pump Run Time (in minutes) - press and hold bu#on for display on LCD.
All programmed sequences are lost when pump is switched off.
To repeat a timed cycle, press the Set-up buon and Start/Hold.
LCD
Displays baery status, pump mode, pump run time, total elapsed time, and flow fault (Figure 1, #1).
When pump enters flow fault, the timer does not reset.
Flow Adjust Potentiometer (pot)
Use a small screwdriver to adjust flow. Gently turn the pot clockwise to increase flow and counterclockwise to decrease
flow. Observe flow indication on the built-in rotameter (not a primary standard flowmeter).
There are two cap screws on the top of the pump. The larger one covers the discharge (exhaust) port. The smaller screw
covers the regulator valve for selecting low flow mode (Figure 1, #15 and 16).
Universal XR Sample Pump Electrical System
Battery Pack
The baery pack contains five Nickel Cadmium (NiCad) cells in series that provide power to the pump motor. The
baery pack is intrinsically safe and should be replaced only with a UL-Listed baery pack manufactured specifically
for Universal XR sample pumps.
Do not charge in hazardous locations. Use only an SKC-approved charger designated for this model to
ensure reliable performance. Failure to do so voids any warranty.
Use of a repaired or rebuilt battery pack voids any warranty and the UL Listing for intrinsic safety .
Failure to follow warnings and cautions voids any warranty.
224-44XRM, PCXR4M, and PCXR8M (MSHA models) contain 4-cell baery packs.
Keypad and LCD
Both are powered by the baery pack. If the LCD does not light up when the pump is turned on, there may be a problem
with the baery. See Troubleshooting.
Motor Control Circuitry
This is a fully electronic system where the voltage applied to the pump motor and the current flowing through the motor
windings are both sampled and controlled by the analog driving circuit. The circuit is calibrated by adjusting two pots
such that flow compensation to within ± 5% accuracy is achieved over the full range of flows and back pressures.

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PCXR4 and PCXR8 Models: If the pump can no longer compensate due to excessive back pressure or the pump’s baery
pack runs low on voltage during sampling, the motor control circuitry will automatically read the voltage fluctuations, the
pump LCD will indicate a flow fault, and the pump will go into Hold mode.
Functional Testing
SKC recommends that a procedure for tracking pump problems and baery life be established as good preventive maintenance
practice. Before beginning functional testing, visually inspect the pump for missing or damaged parts and replace as necessary
(see Pump Disassembly and Pump Reassembly).
Initial Leak Check
Tools
• Universal XR Series pump (fully assembled) • Large syringe
• Water manometer • Pump exhaust port fitting
1. Connect the pump inlet to a water manometer (Figure 6).
2. Leak check the water manometer. Use a large syringe to apply pressure and pinch off tubing aached to the
pump. If there is no drop in the water column, proceed with leak checking the pump. If the water column drops
by one-half inch in 10 seconds, disassemble and reconnect the train. Replace tubing or manometer if necessary.
3. Ensure that there is an O-ring seated in the exhaust port. Insert the exhaust port fiing (Figure 1, #22) into the
exhaust port on the pump and seal it off with a finger.
4. Using a large syringe, apply pressure up to 20 inches.
5. Observe the water column. If the water column drops within 10 seconds, there is a leak in the pump stack. See
Pump Disassembly, Locating and Correcting Leaks. If the water column does not drop, it indicates that there are no
leaks in the system.
If there is a drop in the water column, quickly verify that it is not the water manometer leaking and replace with a known
leak-free manometer if necessary.
SKC recommends periodically testing a water manometer for leaks before performing any leak checks.
Pump Flow Rate Spot Check
Ensure that the baery is fully charged before performing the flow rate “spot check.” SKC recommends performing
preventive maintenance and repair while the pump is on a power supply. Power adapter cables (Cat. Nos. P8000, P8001,
and P8005) and baery adapter cables (Cat. Nos. P8010 and P8013) are available from SKC. See Figures 9 and 10 and
contact SKC to order.
Tools
• Universal XR Series pump (fully assembled) • Dual-ball rotameter, valve, magnehelic gauge
• Small flat-head screwdriver connected with tubing in line and in order
1. Ensure that the pump is in the high flow mode (regulator shut-off screw [Figure 1, #16] turned four full turns
clockwise).
2. Aach the inlet of the pump to the outlet of the magnehelic gauge.
3. Turn on the pump.
4. Ensure the magnehelic gauge reads minimum back pressure.
5. Using a small screwdriver, adjust the flow adjust pot on the front of the pump counterclockwise until the dual-ball
rotameter reads 1000 ml.
6. Observe the dual-ball rotameter. The balls should be fairly steady. If they are bouncing turbulently, see Pump
Disassembly, Locating and Correcting Leaks and Checking Pumping Operation.
7. Using a small screwdriver, turn the flow adjust pot until the rotameter reads 5000 ml and repeat Step 6. If the
pump will not reach 5000 ml, see Pump Disassembly, Locating and Correcting Leaks and Checking Pumping Operation.

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Testing Flow Range Compensation
The Calibration Sheet Addenda in this manual can be used to document this testing.
Compensation is factory preset. SKC recommends that compensation be checked periodically during routine maintenance to
assure pump accuracy. Flow compensation will need to be reset if non-factory repairs have been made (see Pump Reassembly,
Seing Flow Compensation). Do not perform a compensation check unless the baery voltage is at least 6.1 volts.
When checking battery voltage, ensure tester probes are oriented properly to avoid short-circuiting
the battery.
Universal XR Sample Pumps should be able to maintain flow at:
1000 to 2500 ml/min at 40 inches water back pressure
3000 ml/min up to 35 inches water back pressure
4000 ml/min up to 20 inches water back pressure
5000 ml/min up to 10 inches water back pressure
Tools
• Universal XR Series pump (fully assembled) • Dual-ball rotameter, valve, magnehelic gauge
• Small flat-head screwdriver connected with tubing in line and in order
• Calibration Sheet
1. Turn on the pump.
2. With the pump inlet aached to the magnehelic gauge outlet and at minimum back pressure, adjust the flow
adjust pot on the front of the pump until the dual-ball rotameter reads 1000 ml/min.
3. Slowly increase back pressure up to 40 inches. The dual-ball rotameter should remain stable at 1000 ml/min. If
the balls deviate by more than ± 5% during the back pressure increase, it is out of tolerance (see Pump Reassembly,
Seing Flow Compensation).
4. Release back pressure and repeat Steps 2 and 3 at 3000 ml/min and 35 inches water back pressure. If the reading
stays within ± 5% at both 1000 ml/min and 3000 ml/min, the pump should be “in spec” at any other flow point. If
readings deviate by more than ± 5%, see Pump Reassembly, Seing Flow Compensation.
Testing the Pressure Regulator
This is only required if the low flow mode is used frequently. Check the pressure regulator periodically during
routine maintenance to assure pump accuracy. The pressure regulator is factory preset to 20 inches water back pressure at
1500 ml/min. It will need to be reset if non-factory repairs have been made (see Pump Disassembly, Seing the Regulator).
Tools
• Universal XR Series pump (fully assembled) • Dual-ball rotameter, valve, magnehelic gauge
• Small flat-head screwdriver connected with tubing in line and in order
1. Remove the two cap screws from the top of the pump (Figure 1, #15 and 16) and turn on the pump.
2. Place the pump in the low flow mode by turning the smaller screw counterclockwise (Figure 1, #16). This is the
regulator shut-off screw. Turning this screw counterclockwise opens the regulator isolation valve allowing air to
enter the regulator. This screw should be turned four full turns to be sure the valve is fully open.
3. With the pump inlet aached to the magnehelic gauge outlet and at minimum back pressure, set pump flow to
1500 ml/min. Turn the flow adjust pot on the pump until the dual-ball rotameter reads 1500 ml.
4. Close off the inlet to the dual-ball rotameter.
5. Observe the magnehelic gauge. It should indicate 20 inches water back pressure (± 1 inch). If it does not, see Pump
Disassembly, Seing the Regulator.
If pump passes all functional testing successfully, no further service is required.

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Pump Disassembly
Tools
• Universal XR Series pump • Needle nose pliers • Dual-ball rotameter, valve,
• Phillips head screwdriver • Small flat-head screwdriver magnehelic gauge connected with
• Small Allen wrench • Water manometer tubing in line and in order
• Pliers • Pump exhaust port fitting • Large syringe
Removing the Battery Pack
1. Turn the pump over so that the belt clip is facing upward.
2. Using a Phillips head screwdriver, remove the two right-hand screws (Figure 3, #5).
3. Slide the baery straight out to the right.
Lifting up while disconnecting the battery pack can damage the battery pins.
Removing the Back of the Pump Case
1. Using a Phillips head screwdriver, loosen and remove the four screws on the back of the pump case (Figure 3, #7).
2. Holding the filter housing assembly firmly, li the back half of the case (with belt clip) off the front half.
Locating and Correcting Leaks
If the pump failed functional testing, it could be due to a leak. Locate and correct the leak(s). The baery pack, back pump
case, and stack must be removed from the front pump case to perform the following steps (see Pump Disassembly, Removing
the Baery Pack, Removing the Back of the Pump Case, and Disassembling the Stack, Steps 1 through 3).
Filter Housing and Flowmeter Assemblies Leak Check
1. Remove the filter housing (Figure 2, #3) and flowmeter assemblies from the stack (Figure 2, #4). See Pump
Disassembly, Disassembling the Stack, Steps 1 through 3.
2. Aach the filter housing inlet to a water manometer (Figure 6).
3. Place a finger over the short black tubing on the flowmeter.
4. Apply pressure and observe the water column. If it moves, pinch the long black rubber tubing that connects the
filter housing assembly to the flowmeter assembly.
5. Apply pressure and observe the water column.
If the water column remains steady, the leak is in the flowmeter. If the column moves during this test, there is a leak in
the filter housing assembly. Replace filter housing or flowmeter as indicated by this test and repeat Steps 2 through 5.
Regulator and Pulsation Dampener Assemblies Leak Check
1. Remove the regulator assembly (Figure 2, #1) and the two pulsation dampener assemblies (Figure 2, #2) from the
stack by loosening the screw beside the pump exhaust port and the screw beside the regulator isolation valve
(Figure 2, #11). (See Pump Disassembly, Disassembling the Stack, Step 4.)
Ensure there is an O-ring seated at the bottom of the exhaust port. If it is missing, replace it to prevent
the port from leaking.
2. Aach the stack (regulator) inlet (Figure 2, #14) to a water manometer (Figure 6).
3. Cover the inlet passage on the boom of the top half stack (Figure 2, #15) with a finger.
4. Holding the assembly firmly, apply not more than 20 inches of pressure and observe the water column. If there is
movement, there is a leak in one of the assemblies.
5. Remove the boom pulsation dampener assembly (Figure 2, #2) and repeat Steps 3 and 4. If there is no movement,
replace the boom pulsation dampener with a new one and you have fixed the leak. If there is still movement in
the water column, see Step 6.

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6. Remove the top pulsation dampener assembly and repeat Steps 3 and 4. If there is no movement, replace the top
pulsation dampener assembly and repeat Steps 3 and 4. If there is still movement in the water column, see Step 7.
7. Replace the regulator with a new one and repeat Steps 3 and 4.
Throughout this procedure, simply replace the last part removed before the leak went away.
8. Reassemble the stack and retest the pump for leaks (see Functional Testing, Initial Leak Check).
9. Set flow compensation and set regulator (See Pump Reassembly, Se!ing the Flow Compensation and Pump Disassembly,
Se!ing the Regulator).
Boom Half Stack Leak Check
Remove the motor/eccentric assembly from the pump housing (see Pump Disassembly, Disassembling the Stack, Steps 5
and 6). Because it is very difficult to determine the source of leaks in the boom half stack, SKC recommends complete
replacement with Cat No. P21251 (does not include a pressure switch assembly). Aer replacing the half stack with a new
one, perform functional testing (see Functional Testing). Set flow compensation (see Pump Reassembly, Se!ing the Flow
Compensation).
Checking Pumping Operation
If the pump failed the flow range compensation testing during functional testing but does not show signs of a leak,
there could be a problem with the valves. Before checking the valves, ensure that the two stack halves are assembled
and that the motor/eccentric assembly is removed from the pump housing (see Pump Disassembly, Disassembling the Stack,
Steps 5 and 6).
1. With the stack assembled but the motor/eccentric assembly removed, aach the stack (regulator) inlet to a water
manometer (Figure 6).
2. Using a finger, gently push the yoke/diaphragm in the pump housing up and down and observe the water column
on the manometer. The column should rise evenly and steadily with each stroke. If it does not, there is a leaky
valve.
3. Apply vacuum pressure and observe the yoke/diaphragm assembly for movement. The yoke will move toward
the leaking inlet valve.
4. Ensure that the pump exhaust port fiing (Figure 1, #22) is installed on the exhaust port and aach the pump
exhaust port to the water manometer.
5. Apply positive pressure and observe the yoke diaphragm assembly for movement. The yoke will now move away
from the leaking outlet valve.
6. Replace the leaking valve plate assembly (see Pump Disassembly and Pump Reassembly) and retest the pump for
leaks (see Functional Testing, Initial Leak Check).
If the yoke/diaphragm does not move either way, it could mean that both inlet valves are leaky. Perform a visual check
for wrinkled valves or dust under the valves. Replace the entire valve plate if necessary.
Setting the Regulator
This is only required if the low flow mode is used frequently or non-factory repairs have been made. Check the pressure
regulator periodically during routine maintenance to assure pump accuracy. The pressure regulator is factory preset to
20 inches water back pressure at 1500 ml/min.
To perform the following steps the baery pack and back pump case must be removed and the stack partially
disassembled (see Pump Disassembly, Disassembling the Stack, Steps 1 and 2).
In newer pump models, the 1-1/8 x 1-1/4-inch plate on the top of the pump may need to be removed to
access the regulator adjustment screw. This may be done by removing the back cover of the pump. Be
careful not to bind internal parts and wires.
1. Remove both cap screws from the top of the pump (Figure 1, #15 and 16). Li the stack out of the case and remove
the brown plate from the top of the stack.

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2. Aach the filter housing inlet (Figure 1, #9) to the outlet of the magnehelic gauge. Ensure magnehelic gauge reads
minimum back pressure.
3. Turn on the pump and adjust the flow adjust pot on the pump (Figure 1, #7) until the dual-ball rotameter reads
1500 ml.
4. Using a flat-head screwdriver, turn the regulator shut-off screw (Figure 1, #16) counterclockwise four or five turns.
This will open the regulator isolation valve and allow it to work.
5. With the regulator isolation valve open, close off the inlet to the dual-ball rotameter.
6. If the magnehelic gauge reads 20 inches back pressure, no adjustment is needed. If the gauge reads over or under
20 inches, slowly adjust the regulator adjustment screw (Figure 1, #14) until the magnehelic gauge reads 20 inches.
Turn the regulator adjustment screw clockwise to increase pressure and counterclockwise to decrease pressure.
If you exceed 20 inches while turning the regulator adjustment screw, release block on the dual-ball rotameter
inlet, turn the regulator adjustment screw counterclockwise, close off inlet to dual-ball rotameter, and slowly turn
the regulator adjustment screw until the gauge reads 20 inches.
To double-check adjustment, release block on rotameter inlet, then reapply. The gauge should still read 20 inches.
7. When the pump is set at 20 inches back pressure, reinsert the cap screw, and release all back pressure. The pump
is now set for low flow operation between 5 and 500 ml/min. To return the pump to high flow operation, turn the
regulator shut-off screw (Figure 1, #16) clockwise until it is in the closed (down) position. Replace the cap screw.
Disassembling the Stack
1. Remove the two cap screws from the top of the pump (Figure 1, #15 and 16).
2. Carefully li the stack and filter housing assembly straight up and lay on top of the control board to the right or
onto a surface to the le of the pump. Remove the brown plate from the top of the pump.
Wires attach the stack to the control board. Avoid excessive strain on wires.
3. Remove the short black tubing on the flowmeter from the stack (regulator) inlet and pull the flowmeter away from
the pump (the filter housing assembly will come away with it).
4. Remove the top half of the stack by loosening the screw beside the exhaust port and the screw beside the regulator
isolation valve on top of the stack (Figure 2, #1 and 11). The stack will fall into two halves. The top half stack
contains the regulator and pulsation dampener assemblies. The boom half stack contains the valve, yoke/
diaphragm, and motor assemblies.
Leave the two long screws loosened, but in place in the top half stack. This will help to hold all the components of the top
half stack together. Also note the position of O-rings. Ensure that they do not drop out of place during troubleshooting.
5. Using a small Allen wrench, loosen the set screw on each side of the pump housing in the boom half stack
(Figure 8, #14).
6. Gently remove the motor assembly by gripping it with suitable pliers and slowly twisting it while withdrawing it
from the pump housing.
When removing the motor, be careful with the pliers. Do not let them slip and damage the
motor. Do not pull the wires soldered onto the motor.
7. Remove the five screws on the boom valve plate (Figure 2, #6 and 5).
One screw is shorter than the rest and must be replaced in the same hole from which it was removed so that the motor
is not damaged. Keep this screw and its counterpart from the top valve plate separate from the rest of the screws
(Figure 2, #13).

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8. Separate the boom valve plate from the pump housing.
9. Remove the five screws on the top valve plate (Figure 2, #6 and 5).
One screw is shorter than the rest and must be replaced in the same hole from which it was removed (Figure 2, #13).
10. Separate the top valve plate from the pump housing.
11. Remove the buon cap from the side of the pump housing.
12. Remove the yoke/diaphragm assembly by gently pushing the yoke/diaphragm to one side (Figure 2, #8) of the
pump housing and pulling it out of the other side.
Checking the Motor
1. Remove the pump stack (Figure 3, #6) from the case and the motor/eccentric assembly (Figure 2, #9) from the
pump housing (see Pump Disassembly, Disassembling the Stack, Steps 1, 2, 5, and 6).
2. Spin the motor sha by hand and observe its movement. If it does not turn smoothly, does not turn at all, or makes
a grating noise, it needs to be replaced. See Pump Reassembly.
4. With the pump plugged into a DC power supply, carefully apply the positive voltmeter probe to the solder
connection of the yellow wire on the motor (Figure 5) and the negative probe to the negative baery connector
pin (Figure 4, #5). This should indicate a reading of > 1 volt.
5. Repeat this procedure with the solder connection of the orange wire on the motor (Figure 5). This should indicate
a reading of < 1 volt.
For PCXR4 and PCXR8 models: If there is voltage > 5 volts on both solder connections, the pump is in HOLD mode.
Disassembling the Filter Housing
1. Remove the four screws from around the filter housing intake (Figure 1, #10).
2. Remove and discard the filter (Figure 1, #12).
3. Remove the O-ring (Figure 1, #11).
Removing the Control Board and Keypad
The control board is covered with adhesive foam padding. Once removed, do not set foam facedown on a surface. Try to
keep it out of dusty environments.
1. Remove foam padding and carefully set it aside for reuse.
2. Remove the two screws (one screw in 44XR model) on the back of the board (Figure 4, #1).
Do not lose the washers beneath the screws.
3. Remove the screw holding the baery connector (Figure 4, #2).
4. Carefully li board up and push on the back of the window in the front case to separate the keypad from the front
of the pump case (Figure 3, #1). Not applicable to 44XR model.
5. Gently pull the old keypad interface ribbon from the board. Not applicable to 44XR model.
Note how the keypad ribbon connector is inserted before disconnecting it.

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Pump Reassembly
Tools
• Universal XR Series pump (disassembled) • Pliers • Dual-ball rotameter, valve,
• Phillips head screwdriver • Needle nose pliers magnehelic gauge connected
• Small flat-head screwdriver • Thin wooden stick with tubing in line and in order
• Small Allen wrench (popsicle stick)
Reassembling and Replacing the Stack
1. Insert the yoke/diaphragm into the pump housing. Ensure that the opening in the yoke is properly placed to
allow the motor to be installed (Figure 7) and that the oval-shaped O-rings are still in place at the air passages
(Figure 2, #12).
2. Gently push the motor with the soldered wires facing outward into the pump housing until it is boomed.
Ensure the motor is centered in the yoke/diaphragm before pushing it in (Figure 7).
3. Set the top valve plate assembly on top of the pump housing ensuring that the diaphragm fits into the recessed
area in the valve plate. This will help keep the diaphragm centered.
4. Gently press the yoke/diaphragm parallel against the motor counterweight (Figure 7). Once the yoke/diaphragm
has aligned itself with the face of the motor counterweight, press down on the valve plate, replace the short screw
in the top screw hole first, and then replace remaining 4 screws. Tighten the screws in an alternating fashion.
Ensure that the short screw is placed in the top screw hole (Figure 2, #13).
The yoke/diaphragm assembly must be perfectly parallel to the motor counterweight. If it is not, it can cause the motor
to bind (Figure 7).
5. Replace the boom valve plate assembly. Ensure that the components are aligned properly.
Ensure that the diaphragm is fi"ed into the recessed area in the valve plate.
.
6. Replace the short screw in the top screw hole first, and then replace the remaining four screws on the boom valve
plate. Tighten in an alternating fashion.
Ensure that the short screw is placed in the top screw hole (Figure 2, #13).
7. Reassemble the top half stack (two pulsation dampener assemblies and regulator assembly). Ensure that
components are aligned properly (Figure 2).
Do not assemble components O-ring to O-ring.
8. Using a small Allen wrench, tighten the set screw on each side of the pump housing (Figure 8, #14). Turn on
the pump to ensure that the motor runs properly. If it does not, loosen the set screw on each side of the pump
housing and use pliers to carefully back the motor out slightly. Also check that the valve plates are installed
properly. Retest the motor. If it still does not run, ensure the set screws are loosened and remove it. Turn on the
pump and slowly reinsert the running motor until it stops. This will help to determine where the motor is binding.
9. Align the two long screws (Figure 2, #11) in the top half stack with screw holes on top of the boom half stack.
10. Tighten screws.
11. Using needle nose pliers, grip the cable connector on the new keypad interface ribbon and insert it into the plug
on the board. Not applicable to 44XR model.
12. From inside the case, insert the top of the keypad through the slot at the boom of the front case (Figure 3). Not
applicable to 44XR model.
13. Reseat the control board, reinsert screws (one screw in 44XR model) into the back of the control board, and tighten
(Figure 4).
Ensure that a washer is underneath each screw head before tightening them.

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14. Replace screw holding the baery connector (Figure 4, #2) and tighten.
15. Reinsert the baery, turn on the pump, and test the keypad (if applicable).
16. If the keypad is working properly, peel off the keypad backing to expose the adhesive, align it with the
indentations on the front of the pump, and adhere it to the pump case. Not applicable to 44XR model.
17. Align and re-adhere the foam padding on top of the control board (Figure 8).
18. Replace the buon cap on the side of the pump housing.
19. Align the control board wires with the right side of the stack (Figure 8).
20. Look for the original bend in the wiring and fold accordingly.
21. Loop the wiring around the boom of the stack toward the le.
22. Fit the flowmeter assembly under the orange and yellow wires aached to the motor and place the flowmeter so
that it faces the window in the front case of the pump (Figure 1, #13).
23. Aach the short section of black rubber tubing on the flowmeter to the stack (regulator) inlet (Figure 2, #14).
24. Loop the longer black rubber tubing that aaches the flowmeter to the filter housing assembly under the yellow
and orange wires and over the motor. Slide the filter housing assembly into place (Figure 8).
25. Ensure that the stack is seated firmly and that it is level before replacing the back pump cover.
26. Recheck the pump for leaks (see Functional Testing, Initial Leak Check). If it leaks, see Pump Disassembly, Locating and
Correcting Leaks.
27. Set the flow compensation (see Reassembly, Se!ing Flow Compensation).
Setting Flow Compensation
Compensation is factory preset. SKC recommends that compensation be checked periodically during routine maintenance
to assure pump accuracy. Flow compensation will need to be reset if non-factory repairs have been made. Do not set flow
compensation unless the ba!ery voltage is at least 6.1 volts.
Completely reassemble the pump before seing flow compensation (see Pump Reassembly).
1. Remove the compensation pot access screws from the le! side of the pump (Figure 1, #2 and 3).
2. Connect the filter housing inlet (Figure 1, #9) to the magnehelic gauge outlet and ensure minimum back pressure.
3. Turn on the pump.
4. Using a small flat-head screwdriver, carefully adjust the high compensation pot (Figure 1, #3) for minimum flow.
The high compensation pot is also known as pot B. This is a 3/4-turn pot. It needs only a slight turn to
affect the pump flow. Consistently turning it too far can cause damage to the pot.
5. Turn the flow adjust pot on the front of the pump (Figure 1, #7) until the dual-ball rotameter reads 2000 ml/min.
6. Adjust the high compensation pot until the dual-ball rotameter reads 2100 ml/min.
7. Turn the flow adjust pot until the dual-ball rotameter reads 1000 ml/min.
8. Apply forty inches of water back pressure.
9. Adjust the low compensation pot (Figure 1, #2) to correct any deviation from 1000 ml/min.
The low compensation pot is also known as pot A. This is a 3/4-turn pot. It needs only a slight turn to
affect the pump flow. Consistently turning it too far can cause damage to the pot.
10. Turn the flow adjust pot until the dual-ball rotameter reads 2000 ml/min.
11. Apply 40 inches of water back pressure and note the flow.
12. If the flow does not change by more than 5%, check the flow and back pressure as indicated on the calibration
sheet found at the back of this manual. If all measurements are found to be within 5% of the nominal value, the
compensation has been set correctly.
13. If the flow noted in Step 11 changed by more than 5%, note the amount of increase or decrease. Release the back
pressure, and adjust the high compensation pot to cause the flow to change in the same direction and amount as
noted in 11. Repeat Steps 11 through 13 until the flow remains within 5%. Go back to Step 7 and repeat each step
up to Step 13.

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Replacing the Back Pump Case
1. Carefully align the cut-out in the back pump case with the filter housing assembly.
Ensure the stack and wiring sit properly in the front cover (i.e., stack is sitting level, wires are
wrapped around the sides and bottom of stack, and wires are not obstructing the case channel or
screw holes (Figure 8).
2. Gently push the back half of the case down onto the front half. If there is resistance, stop and check that the stack,
filter housing assembly, and wiring are seated properly.
3. Once seated, replace four case screws and tighten in an alternating fashion.
If wiring is obstructing the case channel, use a thin wooden stick to push it into place.
Reassembling and Replacing the Filter Housing
1. Insert a new filter (SKC Cat. No. P2240901) and replace the existing O-ring*.
2. Fit two halves back together.
3. Replace four screws and tighten in an alternating fashion.
4. Check for leaks (see Functional Testing, Initial Leak Check).
* Replace with new O-ring only as needed (SKC Cat. No. P22409 [3 filters, 3 O-rings]).
Replacing the Battery Pack
1. Align baery with grooves on case and baery connector pins on the control board.
Forcing the battery pack when misaligned can damage the battery pins.
2. Carefully push the ba!ery to the le" toward the belt clip until it clicks into place.
It may be necessary to pull up on the belt clip so that the ba"ery pack can slide into place.
3. Replace two ba!ery pack screws and tighten in an alternating fashion.

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Troubleshooting
Tools
• Universal XR Series pump • Pliers
• Phillips head screwdriver • Needle nose pliers
• Small Allen wrench • Soldering iron and solder
Checking the Control Board (PCXR4 and PCXR8 only)
The control board controls all electrical functions. These include flow, compensation, fault protection, and timing. There
are three fault conditions that will stop the pump. All three conditions will be indicated by the same “flow fault” display.
If the pump “faults,” the source of the fault may be determined in the following manner:
1. Remove the baery and back pump case (see Pump Disassembly). Remove adhesive foam padding from the control
board. Locate the two jumper links at the lower right corner of the control board (Figure 4), and remove them by
pulling them straight up from the board. Replace the baery.
2. Start the pump. If the pump faults again, the problem is probably the pressure switch. Remove the baery,
locate the wires that aach to the pressure switch, and desolder or disconnect either one from the control board
(Figure 5). Replace the baery. If the pump still faults, replace the control board (Cat. Nos. P22433U [PCXR8] or
P22433T [PCXR4]). If the pump does not fault, replace the pressure switch (Cat. No. P22417E).
Do not let the loose wire that was removed from the pressure switch touch any other parts.
3. If no fault occurred in Step 2, remove the baery, replace the “V” jumper (Figure 4), replace the baery, and turn
on the pump. If the pump faults and the flow was not adjusted higher than 3 L/min, then the problem is on the
control board. SKC recommends replacing the board. Replacement Control Board Cat. Nos. P22433U (PCXR8) or
P22433T (PCXR4).
4. If the pump did not fault when the “V” jumper was replaced, remove the baery, replace the “I” jumper
(Figure 4), replace the baery, and turn on the pump. If the pump faults and there is minimum back pressure,
the problem is probably on the control board. Replace the control board. Replacement Control Board Cat.
Nos. P22433U (PCXR8) or P22433T (PCXR4).
Use only SKC-approved parts to ensure reliable performance. Failure to do so voids the UL Listing
for intrinsic safety and any warranty.
Failure to follow warnings and cautions voids any warranty.

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Troubleshooting
• Use a known good control board, stack, and motor when troubleshooting. SKC also recommends that a power supply be
used for all testing. Connect it directly to the baery connector on the control board aer removing the baery pack.
Use only SKC-approved parts to ensure reliable performance. Failure to do so voids UL Listing for
intrinsic safety and any warranty.
Failure to follow warnings and cautions voids any warranty.
Pump Problem Possible Solution
224-PCXR4 and PCXR8 Pump LCD doesn’t
light when pump is
turned on and the
motor will not run.
• Check that motor wiring is undamaged and solder joints at the
motor and on the board are in good repair.
• Check the battery for charge and proper voltage.
• Swap with a known good battery for further troubleshooting.
224-PCXR4 and PCXR8 Pump LCD lights
when pump is
turned on, but the
motor will not run.
Turn the flow adjust pot clockwise a few turns. The pot may have
been adjusted to the lowest setting.
• If the motor still does not respond, follow steps above.
• If the motor runs at full speed, turn the flow adjust pot
counterclockwise.
• If the pot cannot be adjusted clockwise, it may have separated
from the control board. Check control board. If pot has
separated, resolder pot and test operation (see Functional
Testing, Flow Rate Spot Check). If pot doesn't operate properly,
replace the control board (Cat. Nos. P22433U [PCXR8] or
P22433T [PCXR4]).
224-PCXR4 and PCXR8 Pump runs when
turned on, but the
LCD will not light.
Check the battery voltage or switch to an alternate power supply
to check the LCD. If it still doesn’t light, it is either a bad LCD
display or a bad diode on the control board. Replace LCD (Cat.
No. P72380, see Pump Disassembly and Pump Reassembly)
or replace the control board (Cat. Nos. P22433U [PCXR8] or
P22433T [PCXR4]).

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Diagrams/Part Description for Figure 1
Use only SKC-approved parts to ensure reliable performance. Failure to do so voids UL Listing for
intrinsic safety and any warranty.
No. Description
1LCD: Displays indicators for all sampler functions.
2 Low Compensation (Pot A): Adjusts factory-set flow compensation. Access screw helps reduce accidental contact or
tampering.
3 High Compensation (Pot B): Adjusts factory-set flow compensation. Access screw helps reduce accidental contact or
tampering.
4ON/OFF Switch: Allows the pump to be shut down completely.
5Anti-tamper Cover: Protects controls from accidental contact or tampering.
6Cover Screw: Fastens anti-tamper cover.
7Flow Adjust Potentiometer: Adjusts pump flow from 1000 to 5000 ml/min.
8Accessory Mounting Screws (2): Secure accessories such as an impinger and trap holder.
9Filter Housing (intake): Air intake port and trap.
10 Filter Housing Screws (4): Secure filter housing.
11 Filter O-ring: Leak seal for filter in housing.
12 Filter (10 micron, nylon): Filters particulates before airflow enters pump.
13 Built-in Flowmeter: Monitors flow changes (not a primary standard flowmeter).
14 Regulator Pressure Adjustment Cap: Accesses regulator pressure adjust screw.
15 Discharge Air Cap Screw: Accesses exhaust port.
16 Regulator Shutoff Cap Screw: Accesses regulator isolation valve.
17 Ba"ery Pack Screws (2): Secures pack to front case.
18 Pump Case Screw (4). Secures back case to front case.
19 Ba"ery Pack: Provides power to pump.
20 Charging Jack: Connector for ba#ery charger.
21 Belt Clip: Secures pump to worker.
22 Exhaust Port Fi"ing