Restek Pack In A Box User manual

www.restek.com 1
Pack In A Box
Dual Piston Pump
Operator’s Manual
cat.# 26408
Chromatography Products
www.restek.com 1-800-356-1688 • 1-814-353-1300

2 www.restek.com
Table of Contents
1. Introduction
1.1 Description of the Dual Head Pump
1.1.1 Pump Features
1.1.2 Wetted Materials
1.2 Specifications for the Dual Head Pump
2. Installation
2.1 Unpacking and Inspection
2.2 Location/Environment
2.3 Electrical Connections
2.4 Solvent Preparation
2.4.1 Solvent Out-gassing and Sparging
2.4.2 Cavitation
2.4.3 Filtration
2.4.4 Solvents With Harmful Effects
2.5 Instrument Installation
2.5.1 Mobile Phase Reservoirs
2.5.2 Inlet Tubing and Filters
2.5.3 Outlet Tubing
2.5.4 Priming the Pump
2.5.5 Long Term Pressure Calibration Accuracy
2.6 Preparation for Storage or Shipping
2.6.1 Isopropanol Flush
2.6.2 Packaging for Shipping
3. Operation
3.1 Front Panel Controls and Indicators
3.1.1 Prime/Purge Valve
3.1.2 Filter/Outlet
3.1.3 Control Panel
3.1.3.1 Digital Display
3.1.3.2 Keypad
3.1.3.3 Status LEDs
3.1.3.4 Power-up Configuration
3.1.3.5 Power-up Tests
3.2 Rear Panel Remote Inputs

www.restek.com 3
4. Theory of Operation
4.1 Mechanical Operation
4.1.1 Liquid System Flow Path
4.1.2 Pump Cycle
4.2 Electronic Control
4.2.1 Microprocessor Control
4.2.2 DC Power Supply
4.2.3 Remote Interfacing
4.2.4 Motor Stall Detector
5. Maintenance
5.1 Filter Replacement
5.1.1 Inlet Filters
5.1.2 Outlet Filter
5.2 Changing Pump Heads
5.2.1 Removing a Pump Head
5.2.2 Cleaning the Pump Head Assembly
5.2.3 Replacing Piston Seals
5.2.3.1 Removing the Seals
5.2.3.2 Cleaning the Piston
5.2.3.3 Replacing the Seals
5.2.4 Changing the Piston
5.2.5 Replacing the Pump Head
5.3 Conditioning New Seals
5.4 Check Valve Cleaning
5.5 Cleaning the Pump
5.6 Cleaning the Cabinet
5.7 Lubrication
5.8 Fuse Replacement
5.9 Battery Replacement
6. Quick Guide to Problem Solving
7. List of Replacement Parts
Appendix A
A.1 Rear Panel Serial Communications Port
A.1.1 Hardware Implementation
A.1.2 Hand Shaking
A.1.3 Command Interpreter
A.2 Rear Panel 4-Pin and 10-Pin Terminal Board Connectors
A.2.1 Pressure Fault and Motor Stall Fault Output
A.2.1.1 Upper and Lower Pressure Limit Range
A.2.2 General Information on Inputs
A.2.3 General Information on Run, Stop, and Enable Inputs
A.2.4 Run and Stop Inputs
A.2.5 Enable Input
A.2.6 General Information on Voltage and Frequency Inputs
A.2.7 Voltage Input
A.2.8 Frequency Input
Appendix B
B.1 Quick Set Pump control
Appendix C
C.1 Column Packer Hardware

4 www.restek.com
1. Introduction
This operator’s manual contains information needed to install, operate, perform user maintenance, and service the Dual Head
High-Performance Constant Pressure Digital HPLC Pump.
1.1 Description of the Dual Head Pump
The Dual Head High-Performance Constant Pressure Pump is designed to be a reliable component for use whereever a constant
pressure must be maintained.
1.1.1 Dual Head Pump Features
• Prime purge valve.
• Autoprime? one button toggles flowrate to maximum for rapid solvent change.
• Inlet and outlet check valves assure reliability.
• 316 stainless steel pump heads.
• Outlet filter.
• Front panel pressure adjustment in 10 psi increments .
• Microprocessor advanced control.
• Tactile response, chemical-resistant front panel keypad.
• Chemical-resistant LED digital display—shows the flow rate and pressure limits.
* Digital stepper motor design prevents flowrate drift over time and temperature, which is a common
problem in analog designs.
* Back panel RS232 serial communications port for complete control and status monitoring.
1.1.2 Wetted Materials
Pump heads, check valve bodies, and tubing are made of type 316 stainless steel. Other materials are synthetic ruby and sapphire
(check valve internals and piston) and fluorocarbon damper (diaphragm).
1.2 Specifications for the Dual Head Pump
Flow Rates 00.00 to 12.00 mL/min (6mL heads)
00.00 to 24.00 mL/min (12mL heads)
Pressure 0 to 9990 psi (without pulse damper)
0 to 6000 psi (with pulse damper)
Pressure Accuracy ±1% of full-scale pressure
Pressure Zero Offset –0.2 psi
Pressure Control Accuracy <10% or 100 psi whichever is larger
Dimensions 5.5” high x 10.375” wide x 17.5” deep
Weight 30 lb
Power 100–240 VAC, 50–60 Hz, 45W (main voltage supply not to exceed ±10%)
Environmental Indoor use only
Altitude Maximum 2000 M
Temperature 10–30° C
Relative Humidity 20–90%
Remote Inputs RS232
2. Installation
2.1 Unpacking and Inspection
Prior to opening the shipping container, inspect it for damage or evidence of mishandling. If it has been damaged or mishandled,
notify the carrier before opening the container. Once the container is opened, inspect the contents for damage. Report any dam-
age to the carrier immediately. Save the shipping container. Check the contents against the packing list.
2.2 Location/Environment
The preferred environment for the dual head pump is normal laboratory conditions. The area should be clean and have a stable
temperature and humidity. The instrument should be located on a stable flat surface with surrounding space for ventilation and
the necessary electrical and fluid connections. (Reference IEC 1010 installation category II, and pollution degree 2 environment)
2.3 Electrical Connections
Unpack the dual head pump; position the pump there so that is at least a four inch clearance on all sides to permit proper ventila-
tion. Using the power cord supplied with the pump, or equivalent, plug the pump into a properly grounded electrical outlet.
WARNING: Do not bypass the safety ground connection as a serious shock hazard could result.

www.restek.com 5
2.4 Solvent Preparation
Proper solvent preparation will prevent a great number of pumping problems. The most common problem is bubble formation,
which may affect the flow rate consistency. Aside from leaky fittings, bubble formation arises from two sources: solvent out-gas-
sing and cavitation. Filtration of HPLC solvents is required.
2.4.1 Solvent Out-gassing and Sparging
Solvent out-gassing occurs because the mobile phase contains dissolved atmospheric gases, primarily N2 and O2. These dissolved
gases may lead to bubble formation and should be removed by degassing the mobile phase before or during use. The best practical
technique for degassing is to sparge the solvent with standard laboratory grade (99.9+%) helium. Helium is only sparingly soluble
in HPLC solvents, so other gases dissolved in the solvent diffuse into the helium bubbles and are swept from the system. Solvent
filtration is not an effective alternative to helium degassing.
It is recommended that you sparge the solvent vigorously for 10 to 15 minutes before using it. Then, maintain a trickle sparge
during use, to keep atmospheric gases from dissolving back into the mobile phase. The sparged solvent must be continually blan-
keted with helium at 2 to 3 psi. Atmospheric gases will dissolve back into non-blanketed sparged solvents within four hours.
Solvent mixtures of water and organic solvents (like methanol or acetonitrile) hold less dissolved gas than pure solvents. Sparging
to reduce the amount of dissolved gas is therefore particularly important when using a solvent mixture.
Even with sparging some out-gassing may occur. A backpressure regulator installed after the detector flow cell will help prevent
bubbles from forming, and thus will limit baseline noise.
2.4.2 Cavitation
Cavitation occurs when inlet conditions restrict the flow of solvent and vapor bubbles are formed during the inlet stroke. The key
to preventing cavitation is to reduce inlet restrictions. The most common causes of inlet restrictions are crimped inlet lines and
plugged inlet filters. Inlet lines longer than 48" (120 cm) or less than 0.085" (2 mm) ID may also cause cavitation.
Placing the solvent reservoirs below the pump level also promotes cavitation. The optimal location of the reservoirs is slightly
above the pump level, but it is adequate to have them on the same level as the pump.
2.4.3 Filtration
Solvent filtration is good practice for the reliability of the dual head pump and other components in a HPLC system. Solvents
should always be filtered through a 0.5 micron filter prior to use. This ensures that no particles will interfere with the reliable
operation of the piston seals and check valves. Solvents in which buffers or other salts readily precipitate must be filtered more
often. After filtration, the solvents should be stored in closed, particle-free bottles.
2.4.4 Solvents With Harmful Effects
All portions of the dual head pump that contact mobile phase are manufactured of type 316 stainless steel, sapphire, ruby, or fluo-
rocarbon polymer. Some of these materials are extremely sensitive to acids (including some Lewis acids) and acid halides. Avoid
using solvents that contain any amount of hydrochloric acid.
Some solvents and salts you should specifically avoid are:
Aqua Regia Hydrochloric Acid
Bromine Hydrofluoric Acid
Chlorine (anhydrous) Hydrofluorsilicic Acid
Copper Chloride Hydrogen Peroxide
Ferric Chloride Iodine
Ferrous Chloride Mercuric Chloride
Freon® 12 (wet) Hydrobromic Acid
Guanidine
Some users of HPLC systems have observed that chloroform and carbon tetrachloride slowly decompose to liberate hydrochloric
acid, which, as noted above, attacks stainless steel. Do not leave these solvents in the system for a prolonged period.
You may also want to avoid ammonium hydroxide. Although ammonium hydroxide will not harm the pump itself, it is likely to
damage the stators and rotors in injection valves.

6 www.restek.com
2.5 Instrument Installation
2.5.1 Mobile Phase Reservoirs
The mobile phase reservoir should be placed at the same level or slightly higher than the pump, never below the pump, and the
inlet tubing should be as short as practical. These steps minimize pressure losses on the inlet side of the pump during refill and
help to avoid bubble formation. These steps are particularly important when using high vapor pressure solvents (hexane, methy-
lene chloride, etc.). Mobile phases should be degassed, filtered, and covered. (See Section 2.4.)
2.5.2 Inlet Tubing and Filters
All inlet lines are supplied in a 36" (91 cm) length, with a 0.085" ID and a 1/8" OD, and are made of a PTFE-based material. Use a
20 micron slip-on inlet filter.
2.5.3 Outlet Tubing
Outlet tubing is not supplied with the pump. It should be 1/16" OD, type 316 stainless steel. Tubing with a 0.020" ID normally is
used before the injection valve. Tubing with a 0.010" inner diameter normally is used after the injection valve. The tubing must be
cut squarely, with no burrs. It should not be crimped and the center hole must be open.
2.5.4 Priming the Pump
Be sure all of the connections downstream of the prime/purge valve are closed. Connect a syringe to the prime/purge valve. Open
the prime/purge valve 1 to 2 turns counter-clockwise. Run the pump at a flow rate of 3 to 5 mL/min. Prime the pump by pulling
mobile phase and any air bubbles through the system and into the syringe (a minimum of 20 mL). Close the prime/purge valve
and stop the pump.
2.5.5 Long Term Pressure Calibration Accuracy
This note applies if your pump is equipped with an electronic pressure transducer. The transducer has been zeroed and calibrated
at the factory. Over the life of the pump, some drift may occur. For example, it is typical for the zero to drift < 10 psi after about 1
year of operation (i.e., with no back pressure on the pump a reading of 1-9 psi may be displayed). A similar drift may also occur at
higher pressures, and are typically less than 1% (e.g. <50 psi at 6,000 psi back pressure).
If pressure calibration and/or drift are a concern, consult the factory. The pump can be shipped back to Restek for recalibration.
Alternatively, written calibration and zero-reset procedures are available. Consult Restek to receive these instructions.
2.6 Preparation for Storage or Shipping
2.6.1 Isopropanol Flush
Disconnect the outlet tubing from the pump. Insert the inlet filter in isopropanol. Open the prime/purge valve and use a syringe
to draw a minimum of 50 mL. Close the prime/purge valve and pump a minimum of 5 mL of isopropanol to exit. Leave the inlet
tubing connected to the pump. Place the inlet filter in a small plastic bag and attach it to the tubing with a rubber band. Plug the
outlet port with the shipping plug, leave a length of outlet tubing on the pump, or cover the outlet port with plastic film.
2.6.2 Packaging for Shipping
CAUTION: Re-package in the original carton, if possible. If the original carton is not available, wrap the pump in several layers of
bubble wrap and cushion the bottom, top, and all four sides with 2" of packaging foam. An HPLC pump is a delicate instrument
and must be carefully packaged to withstand the shocks and vibration of shipment.
3. Operation
3.1 Front Panel Controls and Indicators
Figure 3-1. Dual Head Pump Front Panel

www.restek.com 7
3.1.1 Prime/Purge Valve
CAUTION: When you press the PRIME key, the pump will run at the maximum flow rate. Be sure the prime/purge valve is open.
The prime/purge valve vents the flow to atmosphere and permits efficient priming of the dual head pump. When the valve is
closed firmly fully clock-wise, high-pressure flow is directed to the Filter/Outlet port. When the valve is opened one-half to one
full turn counter clock-wise, pressure is vented and flow exits through the drain port in the prime/purge valve stem assembly.
Suction with a Luer tip syringe at the drain port will purge air bubbles from the pump and reservoir lines (provided there are no
open valves to lines down stream at the injector/column interface). To prime the pump, draw about 20 to 30 mL of mobile phase.
3.1.2 Filter/Outlet
A high-pressure in-line filter (0.5 micron rating) is included at the output of the dual head pump. The Filter/Outlet port is the
high-pressure filter closure and is designed for a 1/16" OD tubing connection.
3.1.3 Control Panel
Special note concerning flow rate limit:
This pump is designed to operate in constant pressure mode (flow rate auto-adjusts to maintain desired pressure). The user may
also lower the maximum flow rate of the pump (12 or 24 mL/min. maximum, depending on model), particularly if pressure is
overshooting while packing small bore columns.
When in Flow MODE (mL/min. LED continuously lit ), the user may lower the maximum flow rate, using the UP & DOWN
arrows as described below. This may be performed before the beginning of a run or during a run. Note that when in maximum
flow mode (mL/min. indicator on constant), the digital display shows only the upper flow rate limit, not the actual flow rate. The
actual flow rate is displayed, using the MODE key, when the mL/min. indicator is blinking.
3.1.3.1 Digital Display
The 4-digit display shows the pump’s maximum flow rate (mL/min.), pressure setting (psi), the set upper or lower pressure limit
(psi), the actual pressure (psi), or actual flow rate (mL/min.) when operating. Choice of display is selected with the MODE button.
Pressure is set from the Pressure Mode Only (steady psi light).
3.1.3.2 Keypad
When pressed, this button alternately starts and stops the pump.
When pressed, this button increases the pressure in pressure mode or the maximum flow rate in flow mode.
When pressed, this button decreases the pressure in pressure mode or the maximum flow rate in flow mode.
When the PRIME button is pressed, the pump runs at the maximum flow rate. It will stop when any button is pressed.
MODE
Use this button to cycle through five display modes: maximum flow rate, pressure setting, upper pressure limit, lower
pressure limit or actual pressure. A status LED to the right of the digital display indicates which mode is active. A
steady psi light indicates set pressure, a flashing psi light indicates actual pressure. A steady mL/min. light indicates
maximum set flow rate, a flashing mL/min. light indicates actual flow rate.
Fast And Slow Button Repeat On The Up And Down Arrow Buttons: If the UP-ARROW or DOWN-ARROW button is held
down for more than approximately one half second, the button press will repeat at a slow rate of approximately 10 times a second.
Once slow button repeat has begun, fast button repeat can be initiated by using a second finger to press down the second arrow
button. During fast button repeat, the button press will repeat at a rate of approximately 100 times a second. Switching back and
forth between repeat speeds can be accomplished by pressing and releasing the second arrow button while holding the first arrow
button down.

8 www.restek.com
3.1.3.3 Status LEDs
ML/MIN (Steady) When lit, the digital display shows maximum flow rate in mL/min.
PSI (Steady) When lit, and not flashing, the digital display shows the pressure setting in psi.
Up and down arrow keys set pressure.
HI PRESS When lit, the display shows the user-set upper pressure limit in psi.
LO PRESS When lit, the display shows the user-set lower pressure limit in psi.
PSI (Flashing) When flashing, the digital display shows the actual pressure in psi.
ML/MIN (Flashing) When flashing, the display shows the actual flow rate in mL/min.
PUMP RUN Lights to indicate that the pump is running.
FAULT Lights when a fault occurs and stops the pump.
3.1.3.4 Power-up Configuration
Pressure Compensation: On power-up, press the PRIME button on the front panel while pressing the Power On switch under the
front display panel. The pump will display a number from 0 to100. This represents the running pressure of the pump which is
0 psi to 10000 psi. Each digit represents 100 psi. To change the pressure compensation number use the up arrow and down
arrow buttons. When you have selected the correct pressure compensation press the RUN button to return to normal operation
of the pump.
Ramp Speed Adjustment & Packing Method : On power-up, press the PRIME button and the down arrow button on the front
panel while pressing the Power On switch under the front display panel. The pump will first display a 0 or a 1 (packing method –
see below) then a number from 10 to 500.
The 10 to 500 number is the percentage of the factory setting for the rate of change algorithm used to adjust the pump’s speed
as it ramps up and down to maintain the pressure setting. To change this percentage, use the up arrow and down arrow buttons.
When you have selected the desired value for ramp speed adjustment, press the RUN button to return to the normal operation of
the pump.
The 0 or 1 is for Fast Packing On or Off. This controls the speed at which the pressure will build in the system.
Pressing the PRIME button on power-up will select Fast Packing On. This is best used for a larger-sized silica column. Pressure
will be allowed to rise to the user set maximum flow rate as rapidly as possible before it is slowed and stabilized at the set pressure.
Pressing the MODE button on power-up will select Fast Packing Off. This is used when column size or material will cause a very
rapid pressure rise before it settles to a low flow rate. If the pressure rise becomes too rapid, the pump will slow down until the
pressure rise slows, and the pump will slow as it narrows in on the set pressure.
Press the RUN button to return to the normal operation of the pump.
NOTE: Lowering the maximum flowrate in flow mode (mL/min. indicator lit) will also have a significant effect on how rapidly
the pressure rises.
Non-volatile Memory Reset: If the pump is operating erratically, there is the possibility that the memory has been corrupted. To
reset the memory and restore the pump to its default parameters, press and hold the up arrow button when the power is switched
on. Release the button when the display reads “rES”. The parameters stored in non-volatile memory (i.e., the flow rate, the pres-
sure compensation, the voltage/frequency select, the lower pressure limit, and the upper pressure limit) will be set to the factory
default values. The head type setting is the only parameter not changed by the non-volatile memory reset function. If the firm-
ware is upgraded to a newer version, a non-volatile memory reset will automatically occur the first time the power is switched on.

www.restek.com 9
3.1.3.5 Power-Up Tests
Display Software Version Mode: The software version can be displayed during power-up by pressing and holding the RUN/
STOP and the up arrow buttons when the power is switched on. Release the buttons when the display reads “UEr”. The decimal
point number displayed on the display is the software version. To exit this mode, press the RUN/STOP button.
Display Software Checksum Mode: If the pump is operating erratically, there is the possibility that the firmware stored in the
program memory integrated circuit (EPROM) has been corrupted. Each version of firmware has a checksum which is printed on
the EPROM label. The pump cover must be removed to gain access to the EPROM which is located on the pump control board;
therefore, this should be done only by a qualified technician. To verify that the firmware has not been corrupted, do the follow-
ing: The software checksum can be displayed during power-up by pressing and holding the RUN/STOP and the down arrow
buttons when the power is switched on. Release the buttons when the display reads “CHE”. After approximately 25 seconds, the
4-digit hexadecimal checksum will be displayed. To exit this mode, press the RUN/STOP button. If the checksum displayed does
not match the checksum printed on the EPROM’s label, the EPROM must be replaced. Note: If the pump is operating correctly,
the firmware version and checksum can be displayed, then written in the manual for future comparison. This will save time dur-
ing future troubleshooting since the pump cover will not have to be removed to read the EPROM label.
Serial Port Loop Back Test Mode: If an external device will not communicate to the pump via the serial port, the serial port loop
back test can be used to verify that the serial port is functioning properly. During power-up press and hold the up arrow and the
down arrow buttons when the power is switched on, then release the buttons. The display must read “C00” for the first half of the
test to pass. Plug in the serial port loop back plug (a modular plug with pins 2 & 5 jumpered together and pins 3 & 4 jumpered
together.). The display must read “C11” for the second half of the test to pass. To exit this mode, press the RUN/STOP button.
3.2 Rear Panel Remote Input
An RS-232C modular jack is provided on the back panel. A computer, with appropriate software, can be used as a remote control
device for pump operation via this connection.
Note: For external connections and serial communications see Appendix A at the back of this manual.
4. Theory of Operation
4.1 Mechanical Operation
4.1.1 Liquid System Flow Path
The flow path of the dual head pump starts at the inlet of the pump head, passes through the pump head and the prime/purge
valve, into the pulse damper, then finally through the bulkhead filter and out the front panel of the pump.
4.1.2 Pump Cycle
The pump cycle consists of two phases, the pumping phase and the refill phase.
During the operation of the pump, one pump piston displaces fluid at a constant rate from one head, while the other piston is
refilling the other pump head with fluid. When that piston is finished displacing fluid, the other piston immediately starts. This
results in a constant, stable flow from the pump at high pressure.
Figure 3-2. Dual Head Pump Rear Panel

10 www.restek.com
4.2 Electronic Control
4.2.1 Microprocessor Control
The pump is controlled by hybrid microprocessor circuitry which (1) provides control signals to the motor power board, (2)
interfaces with the keyboard/display, (3) receives signals from the pressure transducer and refill flag, and (4) provides external
input/output and remote control interfacing. Firmware programming is stored in an EPROM.
The motor power board contains programmed logic components which (1) provide suitable motor micro-stepping modes, (2)
allow appropriate motor power adjustment, (3) maximize motor power output, (4) reduce motor resonance effects, and (5)
customize motor stepping uniformity. MOSFET power transistors efficiently control the motor power provided by a 36 VDC
linear power supply. This board also provides the 12 VDC (linear power supply) and the 5 VDC (switching power supply) used
by the pump circuits.
A specially shaped cam provides refill in a fraction of the full cam revolution. The remaining revolution of the cam provides a
linear piston displacement for constant flow of the mobile phase.
The flow rate of any high-pressure pump can vary, depending on the operating pressure and the compressibility of the fluid being
pumped. The pump is calibrated at 1,000 psi using an 80:20 mixture of water and isopropanol.
The dual head pump has a built-in pressure transducer, which senses fluid pressure. The output is sent to the microprocessor
circuit, which provides the information presented on the digital display. This pressure information is compared with the user-set
upper and lower pressure limits to control pump shut-off if the limits are exceeded.
4.2.2 DC Power Supply
A switching regulator provides the DC voltage necessary to run the motor and electronics. AC input power for the pump must be
between 85 and 265 VAC, and 47 to 63 Hz. The AC line is filtered and fused by the power entry module. Internally a fuse located
on the motor drive printed circuit board protects the motor supply voltage, and the low voltage conversions have thermal and
short-circuit protection.
4.2.3 Remote Interfacing
An RS-232C modular jack is provided on the back panel. See Section 3.2 for information on pump operation via this connection.
4.2.4 Motor Stall Detector
The motor can stall and create a loud buzzing sound if the flow path connected to the pump’s outlet becomes plugged, if the pres-
sure exceeds the maximum pressure rating of the pump, or if the mechanism jams. In the event a motor stall occurs, the electrical
current being supplied to the motor is turned off and the fault light is turned on.
The motor stall detector is enabled or disabled during power-up by pressing and holding the RUN/STOP and PRIME buttons
when the power is switched on. Release the buttons when the display reads “SFE”. To enable the motor stall detector press the
up arrow button and the display will read “On”. To disable the motor stall detector press the down arrow button and the display
will ready “OFF”. To exit this mode and store the current setting in non-volatile memory, press the RUN/STOP button.
The motor stall detector uses a timer to determine if the camshaft has stopped turning or if the refill switch is defective. The timer
begins timing after the pump accelerates or decelerates to its set-point flow rate. If the motor stall detector has been enabled, and
the cam shaft stops turning or the refill switch stops operating, the fault will be detected between the time it takes to complete 1 to
2 pump cycles. A pump cycle is defined as the time it takes for the camshaft to complete one complete revolution. One revolution
of the camshaft produces a delivery phase and a refill phase. Each specific flow rate has a corresponding cycle time. For a pump
with an analytical (standard) 10 mL/min. pump head, the cycle time is approximately: 30 seconds at 0.1 mL/min., 3 seconds at
1.00 mL/min., and 0.3 seconds at 10.00 mL/min. For a pump with a preparative (macro) 50 mL/min. pump head, the cycle time is
approximately: 30 seconds at 0.4 mL/min., 3 seconds at 4.00 mL/min., and 0.3 seconds at 40.00 mL/min.
The fault is canceled by using one of the following methods: (1) by pressing the RUN/STOP button on the front panel, (2) by
sending a stop command “ST” via the serial communications port on the back panel, or (3) by connecting the PUMP-STOP input
to COM on the back panel, or removing the connection between the PUMP-RUN input and COM if the PUMP-STOP input is
permanently jumpered to COM on the back panel. Note: the PUMP-RUN, PUMP-STOP, and COM are an option and do not
exist on the standard pump.
5. Maintenance
Cleaning and minor repairs of the dual head pump can be performed as outlined below.
Note: Lower than normal pressure, pressure variations, or leaks in the pumping system all can indicate possible problems with the
piston seal, piston, or check valves. Piston seal replacement could be necessary after 1000 hours of running time. See Section 5.2.3.