Walchem ehe series User manual

EHE Series
Electronic Metering Pump
Instruction Manual
Five Boynton Road Hopping Brook Park Holliston, MA 01746 USA TEL [phone] FAX [phone]
Website: www.walchem.com

Notice
© 2007 WALCHEM Corporation
Five Boynton Road, Holliston, MA 01746 USA
tel [phone] fax [phone]
All Rights Reserved
Printed in USA
Proprietary Material
The information and descriptions contained herein are the property of WALCHEM
Corporation. Such information and descriptions may not be copied or reproduced by any
means, or disseminated or distributed without the express prior written permission of
WALCHEM Corporation.
This document is for information purposes only and is subject to change without notice.
Statement of Limited Warranty
WALCHEM Corporation warrants equipment of its manufacture and bearing its
identification to be free from defects in workmanship and material for a period of two
years from date of delivery from the factory or authorized distributor under normal use
and service and otherwise when such equipment is used in accordance with instructions
furnished by WALCHEM Corporation and for the purposes disclosed in writing at the
time purchased, if any.
WALCHEM Corporation’s liability under this warranty shall be limited to replacement or
repair, F.O.B. Holliston, MA U.S.A. of any defective equipment or part which, having
been returned to WALCHEM Corporation, transportation charges prepaid, has been
inspected and determined by WALCHEM Corporation to be defective.
THIS WARRANTY IS IN LIEU OF ANY OTHER WARRANTY, EITHER EXPRESS OR
IMPLIED, AS TO DESCRIPTION, QUALITY, MERCHANTABILITY, FITNESS FOR ANY
PARTICULAR PURPOSE OR USE, OR ANY OTHER MATTER.
P/N E00022.F3
Jun 2007
1

TABLE OF CONTENTS
Thank you for choosing a Walchem EH Series metering pump. This instruction manual deals with the
correct installation, operation, maintenance and troubleshooting procedures for the EHE model metering
pumps. Please read through it carefully to ensure the optimum performance, safety and service of your
pump.
1.0 INTRODUCTION................................................................................................................3
1.1 Safety and Caution Notes ..............................................................................................3
1.2 Principle of Operation.....................................................................................................3
1.3 Specifications.................................................................................................................4
1.4 Dimensions.....................................................................................................................5
2.0 INSTALLATION.................................................................................................................6
2.1 Unpacking ......................................................................................................................6
2.2 Location..........................................................................................................................6
2.3 Supply Tubing ................................................................................................................8
2.4 Discharge Tubing...........................................................................................................8
2.5 Installing Injection/Back Pressure Valve ........................................................................9
2.6 Electrical.........................................................................................................................9
3.0 OPERATION....................................................................................................................10
3.1 Priming.........................................................................................................................10
3.2 Adjustment ...................................................................................................................10
3.3 Calibration....................................................................................................................10
3.4 External Control............................................................................................................11
3.5 STOP Function.............................................................................................................17
3.6 AC Power Interruption..................................................................................................17
4.0 MAINTENANCE...............................................................................................................18
4.1 Diaphragm Replacement..............................................................................................18
4.2 Valve Replacement......................................................................................................18
4.3 Tubing ..........................................................................................................................18
5.0 EXPLODED VIEW AND PARTS GUIDE.........................................................................19
5.1 How to order parts for your metering pump..................................................................19
5.2 Accessories (Not shown)..............................................................................................20
5.3 EHE30, 35, 45 Liquid End Exploded View...................................................................21
5.4 EHE 55 Liquid End Exploded View ..............................................................................23
5.5 Drive Control Components...........................................................................................25
5.6 Assembly Part Numbers...............................................................................................26
5.7 Spare Parts Kit.............................................................................................................26
6.0 TROUBLESHOOTING.....................................................................................................27
7.0 SERVICE POLICY ...........................................................................................................28
2

1.0 INTRODUCTION
1.1 Safety and Caution Notes
Always wear protective clothing, eye protection and gloves before working on or near a
metering pump. Follow all recommendations of the supplier of the solution being
pumped. Refer to the MSDS from the solution supplier for additional precautions.
Walchem EH Series metering pumps should be installed where ambient temperatures do
not exceed 122°F (50°C) or do not fall below 32°F (0°C), or where pump or tubing are
directly exposed to sunlight.
WARNING Risk of electrical shock! This pump is supplied with a grounding
conductor and grounding-type attachment plug. To reduce the risk of electrical shock, be
certain that it is connected only to a properly grounded, grounding type receptacle with
ratings conforming to the data on the pump data plate. Prior to performing any
maintenance on a pump, disconnect the pump from the electrical power source.
Plumbing Precautions
All tubing must be securely attached to the fittings prior to starting the pump (see Section
2.3). Only use Walchem tubing with your pump. Tubing should be shielded to prevent
possible injury in case of rupture or damage. UV resistant tubing should be used if the
tubing is exposed to UV light. Always adhere to local plumbing codes and requirements.
Be sure that the installation does not constitute a cross connection. Walchem is not
responsible for improper installations. Prior to performing any maintenance on a pump,
depressurize the discharge tubing.
If you are pumping downhill or into little or no system pressure, a back pressure/anti-
syphon device must be installed to prevent over-pumping. Contact your Walchem
distributor for additional information.
Solution Compatibility
CAUTION! This pump has been evaluated for use with water only. The suitability of this
pump for use with liquids other than water, such as acid and alkaline, is the responsibility
of the user. For liquids other than water, select the best-suited liquid end material
combination using a chemical compatibility chart.
1.2 Principle of Operation
The EH Series electronic metering pump consists of a pump unit, a drive unit, and a
control unit. The drive unit is an electromagnetic solenoid. When the solenoid coil is
energized by the control unit the armature shaft moves forward due to the magnetic force
of the solenoid. The shaft is attached to a PTFE faced diaphragm which is part of the
pump unit. The diaphragm is forced into the pump head cavity decreasing volume and
increasing pressure which forces liquid in the pump head out through the discharge check
valves. When the solenoid coil is de-energized, a spring returns the armature to its starting
position. This action pulls the diaphragm out of the head cavity increasing volume and
decreasing pressure. Atmospheric pressure then pushes liquid from the supply tank
through the suction check valves to refill the pump head.
3

1.3 Specifications
EH E35 E 1 - PC V
1 2 3 4 5 6
1 Pump Series
EHE Electronic metering pump with external pulse control or manual speed
control (adjustable to 360 strokes per minute) and manually adjustable
stroke length. (Typical turndown ratio 1800:1.)
2 Capacity/Pressure Rating
Output Capacity
(GPH) (mL/min)
Output per stroke
(mL) Maximum Pressure
Size min max min max min max (PSI) (MPa)
Conn. Size (in)
Tubing O.D.
E30 0.0031 5.5 0.189 340 0.189 0.94 150 1.0 ½
E35 0.0047 8.5 0.289 520 0.289 1.44 105 0.7 ½
E45 0.0067 12.0 0.417 750 0.417 2.08 60 0.4 ½
E55 0.0111 20.0 0.694 1250 0.694 3.47 30 0.2 ½
3 Control Module
E For use on all EHE models, features analog and external pulse control
with pulse divide and multiply capability.
4 Voltage
1115VAC, 50/60 Hz
2 230VAC, 50/60 Hz
5 Liquid End
Liquid End
Code Pump Head & Fittings Diaphragm* Valve
Balls Valve Seat Valve
Seals Gasket Tubing
VC PVC PTFE CE FKM FKM PTFE PE
VE PVC PTFE CE EPDM EPDM PTFE PE
VF PVC PTFE PTFE EPDM EPDM PTFE PE
V6 PVC PTFE SS EPDM EPDM PTFE PE
PC GFRPP PTFE CE FKM FKM PTFE PE
PE GFRPP PTFE CE EPDM EPDM PTFE PE
FC PVDF PTFE CE PCTFE PTFE PTFE PE
VM<M-PVC PTFE CE FKM PTFE PTFE PE
<E55 Model only * Bonded to EPDM
Materials of Construction
CE Alumina ceramic PCTFE Polychlorotrifluoroethylene
EPDM Ethylene propylene diene monomer PE Polyethylene
FKM Fluoroelastomer PTFE Polytetrafluoroethylene
GFRPP Glass fiber reinforced polypropylene PVC Polyvinylchloride (translucent)
M-PVC Machined polyvinylchloride PVDF Polyvinylidenefluoride
SS 316 Stainless steel
6 Special Head Options
Blank Standard ½” tube connection with tube style injection & foot valves.
VStandard ½” tube connection with back pressure/anti-syphon valve, tube style injection & foot valves.
T¾” NPT (male) pipe thread connection. No accessory valves.
P¾” NPT (male) connection with back pressure/anti-syphon valve.
4

Adjustment Range
Recommended stroke length adjustment range 20% to 100%
Recommended frequency adjustment range 0 to 360 strokes per minute
Operating Conditions
Ambient temperature 32 to 122°F (0 to 50°C)
Relative humidity 30 to 90% non-condensing
1.4 Dimensions
OUT
LCE
AB
IN
J
D
H
W
F
T
S
R
X
Note: The Stop pin on the stroke length adjustment knob can be
broken off with enough force and the pump can be turned up
above 100%. This will cause damage to the pump and void the
warranty.
Model A B C D E F H J L W
EHE 30
35 E1 E2
-VC
-PC
-V6
-FC
-VE
-PE
-VF 6.06 1.04 7.76 6.42 0.65 0.67 9.69 3.15 9.53 5.75
EHE 45 E1
E2
-VC
-PC
-V6
-FC
-VE
-PE
-VF 6.06 1.14 7.83 6.42 0.75 0.67 10.00 2.80 9.72 5.75
EHE 55 E1
E2
-VC
-PC
-V6
-FC
-VE
-PE
-VF 6.06 1.42 8.13 6.42 0.85 0.67 10.45 2.38 10.12 5.75
EHE 55 E1
E2 -VM 6.06 1.42 8.13 6.42 0.91 0.67 10.45 2.38 10.17 5.75
Mounting Dimensions R S T X
EHE all variations 5.20 4.50 1.00 0.28
All dimensions in inches
5

2.0 INSTALLATION
2.1 Unpacking
Open the shipping carton and inspect contents for damage. If any items are missing or
damaged contact your local distributor to arrange for replacement.
Pumps are pre-primed with water at the factory. If the application is not compatible
with water, drain and dry before use. Be sure to remove caps from fittings before
attaching tubing.
CAUTION:Head bolts may have loosened during storage or shipment. Be sure to
check and tighten to 19 lb-in torque, if necessary.
2.2 Location
Choose a location for the pump which is clean, dry, close to an electrical outlet, and
allows convenient access to stroke length control, frequency control, and tubing
connections. Avoid areas where ambient temperature exceeds 122°F (50°C) or falls below
32°F (0°C), or where the pump or tubing would be exposed to direct sunlight.
This pump is cord connected and not intended for permanent mounting to a building
structure. However, temporary mounting to stabilize the pump during operation may be
necessary as long as tools are not required for the installation or removal of the pump.
Flooded suction (mounting the pump below the level of liquid in the supply tank) is
strongly recommended, especially when pumping liquids that readily generate gas
bubbles. Sodium hypochlorite and hydrogen peroxide are common examples of such
liquids. (See Figure 1.)
6

Figure 1 Figure 2 Figure 3
Flooded Suction Shelf Mount Tank Mount
If flooded suction mounting is not possible, a shelf adjacent to (but not directly above) the
supply tank often works well (see Figure 2). The supply tank or cover can also be used if
it has provisions for mounting a pump (see Figure 3). In any case, the total suction lift
should not exceed 5 ft (1.5m). See Figure 4 for reference.
Point of in
j
ection
Coupling nut
Injection check valve
PVC pipe
tubing straightener
(user supplied)
Foot valve
Coupling nut
Figure 4 Connecting Tubing
7

2.3 Supply Tubing
The supply tubing run should be as short as possible. For flooded suction mounting,
install a shut-off valve with an appropriate tubing connector at the tank outlet. Cut a
length of tubing from the coil supplied and install between the shut-off valve and the
pump inlet fitting. For suction lift applications, install a foot valve on one end of suction
tubing and cut the tubing to a length such that the foot valve hangs vertically about 1 in
(25mm) above the bottom of the tank. Avoid any loops in the tubing run that could form a
vapor trap. Running the tubing through a length of rigid pipe will help to keep tubing
straight (see Figure 4). Total vertical suction lift should be no more than 5ft. (1.5m).
Attach tubing as shown in Figure 5. First slide the coupling nut, small end first, onto the
tubing. Then slide on the clamp ring. Next push the tubing onto the tubing adapter fitting.
(Tips: Place adapter fitting on a flat surface such as a table top and press tubing down on
top of it all the way to the lip of the adapter fitting. If the tubing is stiff from cold, dip the
tubing end in hot tap water for a few minutes so it will slide on and flare out more easily.
Slide clamp ring down until it tightens over the adapter fitting. Then slide coupling nut
down as far as it will go. Insert this arrangement into the suction valve housing. With one
hand holding tubing and applying slight downward pressure, tighten the coupling nut until
secure.
WARNING: All fittings and coupling nuts should be tightened by hand. If necessary,
small pliers may be used to make it snug. DO NOT use excessive force or large wrenches.
TUBING
ADAPTER
CLAMP
RING
COUPLING
NUT
Figure 5 Attach Tubing
2.4 Discharge Tubing
Cut a length of tubing long enough to go from the pump to the application (injection)
point. Additional tubing can be ordered from your distributor. Avoid sharp bends or
kinks in the tubing and protect the tubing from sharp edges that could chafe or cut it. If
applicable, install the injection valve in 1/2” NPT thread at the injection point and connect
the discharge tubing to the injection valve.
Attach the tubing as described above, installing it to the discharge valve housing.
8

2.5 Installing Injection/Back Pressure Valve
A fitting or tee with 1/2” NPTF threads and with sufficient depth will accept the injection
valve assembly. If required, trim off an amount of the extension tip until it fits your fitting
or tee. (Fig. 6.)
The position of the injection/back pressure valve can be at any orientation as long as the
spring is retained in the valve. DO NOT REMOVE THE SPRING. Be sure to check and
replace the spring as needed. Attach the tubing following the same instructions in section
2.3, connecting the supply tubing.
In addition to preventing backflow from pressurized lines, the injection valve acts as a
back pressure valve when pumping into atmosphere or low pressure applications.
IMPORTANT: Always install the injection/back pressure valve at the end of the
discharge tubing to prevent over-pumping in atmospheric or low pressure situations.
Figure 6 Injection Valve
See Section 5.0 for complete liquid end parts list and exploded view.
2.6 Electrical
WARNING: Risk of electrical shock! This pump is supplied with a grounding
conductor and grounding-type attachment plug. To reduce the risk of electrical shock, be
certain that it is connected only to a properly grounded, grounding type receptacle.
Connect the pump power cord to a GROUNDED outlet supplying proper voltage. Avoid
branch circuits that also supply power to heavy machinery or other equipment that could
generate electrical interference.
9

3.0 OPERATION
3.1 Priming
CAUTION:With enough leverage, the stroke length knob on the EHE pumps can be
forced above 100% (by breaking the stop pin). This will damage the pump and will void
the warranty.
Install the pump as described above. With the pump plugged in but not pumping, set
stroke length at 100% and frequency at 360 (use the ¿or Àbuttons as necessary to adjust
the frequency). Disconnect the discharge tubing from the injection valve. Push the
START/STOP button to start the pump. As soon as liquid enters the discharge tubing at the
pump head, push the START/STOP button again to stop the pump. Reconnect the
discharge tubing to the injection valve.
If the pump does not self prime, remove the check valve housing on the discharge and
suction sides to make sure the valve cartridges and gaskets are in correct positions (see
Section 4.2). Remove and shake cartridges to make sure ball is loose inside. Wetting
cartridges before re-installing will help in priming.
3.2 Adjustment
The pump will operate best with the stroke length at 100%. If less than full output is
required, set the frequency to the desired percentage of maximum.
Example: Model EHE30E1-VC has maximum output of 5.5 GPH.
Desired output is 4.0 GPH.
4.0 ÷ 5.5 = 0.73 or 73%. 73% of 360 is 263.
Press the ¿or Àbuttons as necessary to set the frequency to 263.
If very low outputs are required, it will be necessary to also reduce the stroke length.
(Minimum recommended stroke length is 20%.)
3.3 Calibration
If exact output calibration is required,
first prime and adjust the pump as above.
Then connect a calibration column to the
suction side of the pump. Turn the pump
on for one minute and read the amount of
liquid pumped from the column. Adjust the
frequency up or down as necessary and check
the output again. When the desired output is
reached, disconnect the calibration column and
reconnect the suction tubing. (See Figure 7.)
Figure 7 Calibration
10

3.4 External Control
The EHE Series is able to operate in both digital and analog external modes. An external
stop function is also available.
Display/Keypad Overview
UP key. Increases
numeric values. Is
used with EXT key to
select external modes.
DOWN key. Decreases
numeric values. Is used
with EXT key to select
external settings.
WAIT indicator. Visible
when pump is in standby
mode.
Alpha/numeric display. Indicates
stroke frequency, external mode or
external settings.
Start/Stop key.
Manually starts or stops
the pump. This key is
used in setting external
modes and values.
EXT indicator. Visible
when pump is operating
via external input
operation.
EXT key. Push to set
pump for external input
operation. This key is
also used to select
which external mode
and settings.
STOP indicator. Visible
when the pump is stopped
via external signal. The
p
um
p
sto
p
s
p
um
p
in
g
.
OVER indicator. Visible when an
input signal exceeds the pump’s
360 spm capability or when an
input is received during an external
'Stop'.
SET indicator. Visible
when pump external mode
and/or setting are being
selected.
3 6 0 ON light. Indicates AC
power to the pump and
goes on and off with
each stroke.
2
1345678
+
+
-
-
POWER GROUND
GREEN
BLACK
HOT
WHITE
NEU Digital Input
Stop Input
Analog Input
Sensor Power
DC 12V
10 mA max.
External Signal
Cab
l
e
Power
cord
Figure 8
11

EH-E Quick Reference Guide
S/S EXT
FROM: PRESS: TO:
Start/Stop Key External Key
WAIT
MODE
S/S
EXT
EXT
+
EXT
+
Run in manual mode
Run in ternal mode
EXT
SET
SET
external mode
external values
S/S
Decrease frequency (1 to 360 SPM)
Increase frequency (1 to 360 SPM)
S/S
Return to and stop pump operation
WAIT
RUNNING IN
MANUAL MODE
EXT
RUNNING IN MODE
SET
EXTERNAL MODE
OR Toggles between DIG (multiply or divide) and
ANA (milliamp input)
S/S
Accept data and return to mode
WAIT
Return to and stop pump operation
WAIT
Decrease frequency (1 to 360 SPM)
Increase frequency (1 to 360 SPM)
SET
EXTERNAL VALUES
DIG
EXT
S/S
ANA
Select '/' (divide) or 'X' (multiply
Increase value (1 to 999)
Decrease value (1 to 999)
Accept data and return to mode
WAIT
S/S
Accept data and return to mode
WAIT
EXT
Scroll through the following selections:
A
P
A
P
nalog signal level (point 1)
ump speed (point 1)
nalog signal level (point 2)
ump speed (point 2)
Increase value (A from 0.00 to 20.0mA)
(P from 0 to 360 SPM)
Decrease value (A and P)
WAIT
Increase Decrease
Pump Speed RUN
MANUAL RUN EXTERNAL SET EXTERNAL MODE SET EXTERNAL VALUES
S/S S/S S/S S/S S/S
Incr Decr
Pump Speed DIG ANA
DIG: ANA:
toggles
between
X, / to scroll thru
4-20, 20-0
20-4, 0-20
Incr Decr
Numeric Value
12

Digital Mode
In digital mode, the pump accepts a pulse signal from a flowmeter or other instrument.
The pump can be set to divide pulses by a factor of 1 to 999; or in multiply mode, 1 input
pulse can produce 1 to 999 pump strokes. The minimum pulse width for input pulses is
10msec.
Connecting a digital input device
Disconnect AC power to the pump. Remove the four screws from the terminal block cover
and remove the cover. Remove the cord nut and bushing from the terminal block cover.
Remove the terminal block from the connector. Slide the nut and bushing over the
external control cable and insert the cable through the terminal block cover. Strip 1/4”
insulation from conductors and connect the positive side to terminal 7 and the negative
side to terminal 8. (See Figure 8 and the schematic, below.)
423 5678
Power
G
round
Digital Input
Sensor Power
DC 12V
10 mA max.
+-
White
NEU Black
HOT Green
Connecting a digital input to multiple pumps in parallel
Pump #1
Input Connector Pump #2
Input Connector Pump #5
Input Connector
CAUTION:
1. Polarity Sensitive. Be sure to connect the POSITIVE to POSITIVE
and GND to GND with each connection.
2. DO NOT SUPPLY ANY TYPE OF POWERED INPUT TO THE
PUMPS! Contact closure ONLY is acceptable or damage to the
pumps will occur.
3. Maximum current rating of the pump input is 10mA. Each pump
draws approximately 2mA. There is a 5 PUMP LIMIT of pumps in
parallel.
4. Make sure the switching device can handle the maximum current in
the system. Current = 2mA x # of Pumps
+
+
+
GND
GND
GND
4 5 6 7 8 4 5 6 7 8 4 5 6 7 8
Open Collector (reed switch)
Or
Opto-Isolator
13

Sensor Power
The control circuit of the EHE series has the ability to provide 12 VDC at up to 10 mA to
power a Hall effect sensor or similar device.
Connect the sensor power leads to terminal 4 (positive) and terminal 8 (negative) of the
terminal block.
Settings
Start with pump in the WAIT state. If it is not currently in wait, press START/STOP
once.
Press ¿and EXT simultaneously.
The SET indicator is highlighted and DIG (digital) or ANA (analog) will be displayed.
1. Set it to digital mode
If DIG is displayed, press START/STOP to accept that mode.
You will be returned to the WAIT state.
If ANA is displayed, press the ¿button to change to DIG and then press
START/STOP to enter that choice.
You will be returned to the WAIT state.
2. Set multiply or divide
To set values for digital operation, press EXT and Àsimultaneously. The display
will show / or X and a 3 digit number. Now pressing the EXT button will
alternate between X (multiply) and / (divide).
3. Set the value
¿or Àwill increase or decrease the multiplier or divider. Pressing a button
once will change the value by one. Holding a button down will continuously
increment or decrement the value, slowly at first, then rapidly. Press
START/STOP to accept values and return to WAIT.
Press EXT to operate the pump in external mode. The pump will now respond to
the incoming pulse signal. The stroke length can be adjusted manually to set the
volume pumped per stroke.
14

Analog Mode
CAUTION: Open loop signal voltage must not exceed 25 VDC. If the signal voltage is
greater than 25 VDC, power down the signal source prior to connection.
In analog mode the pump will accept a milliamp signal and produce a pump speed
proportional to the signal level received. The input resistance of the analog signal is
250Ω. The pump’s response can be fine tuned by variable set points to meet system
requirements.
Connecting an analog signal device
Disconnect AC power to the pump. Remove the four screws from the terminal block cover
and remove the cover. Remove the cord nut and bushing from the terminal block cover.
Remove the terminal block from the connector. Slide the nut and bushing over the
external control cable and insert the cable through the terminal block cover. Strip 1/4”
insulation from conductors and connect the positive side to terminal 5 and the negative
side to terminal 8. (See Figure 8 and the schematic below.)
423 5678
Power
G
round
A
nalog Input
Sensor Power
DC 12V
10 mA max.
+-
White
NEU Black
HOT Green
+-
Settings
The pump’s response to a 4 to 20 milliampere signal can be adjusted to meet almost any
need. The adjustment is done by selecting two points. A signal level and a pump speed
are entered for each point. These two points determine a straight line and the pump speed
resulting from any given signal will be defined by that line. The factory settings for point
1 are 4.0 mA, 0 spm and for point 2 are 20.0 mA, 360 spm. An ‘A’ in the leftmost
position of the display indicates the data shown is Analog signal level. A ‘P’ indicates
Pump speed. The 1 on the right side of the display is highlighted when viewing or
changing data for point 1. The 2 is highlighted to indicate data for point 2.
Start with pump in the WAIT state. If it is not currently in wait, press START/STOP
once.
15

1. Set analog mode.
Press ¿and EXT simultaneously.
The SET indicator is highlighted and DIG (digital) or ANA (analog) will be
displayed.
If ANA is displayed, press START/STOP to accept that mode.
You will be returned to the WAIT state.
If DIG is displayed, press Àto change to ANA and then press START/STOP to
enter that choice. You will be returned to the WAIT state.
2. Set values
To set values for analog operation, press EXT and Àsimultaneously. The display
will show A04.0 (or some value between 00.0 and 20.0 mA) with the point 1
indicator highlighted. Press ¿or Àto adjust the value to the desired analog
signal level for point 1.
Press EXT to display the pump speed for point 1. The display will show P0 (or
some value between 0 and 360 spm) with the point 1 indicator highlighted. Press
¿or Àto adjust the value to the desired pump speed for point 1.
Press EXT again to display the analog signal level for point 2, which can be
adjusted as for point 1. Pressing EXT a third time will display the pump speed for
point 2m which can be adjusted as for point 1.
Continued pressing of EXT key will scroll through the above four parameters for
review or adjustment. When settings are as desired, press START/STOP to
accept the new values and return to WAIT.
Press EXT to operate the pump in external mode. The pump speed will now be
determined by the level of the milliamp signal as shown in the graph. The stroke
length can be adjusted manually to set the volume pumped per stroke.
04 81216
A
1
A
2
90
180
270
360
P1
P2
INPUT SIGNAL, mA
PUMPFRE
Q
UENCY,SPM
20
16

3.5 STOP Function
The EHE series pump also includes a STOP function which allows an external signal to
stop the operation of the pump.
A switch or solid state device capable of switching 5 VDC at 2 mA can be connected to
terminals 6 (positive) and 8 (negative) of the terminal block. Closing this circuit
temporarily interrupts pump operation. Opening this circuit resumes pump operation. If
the pump is operating in external digital mode, any pulses received while the pump is
stopped will be saved (up to a maximum of 255). When pump operation resumes, saved
pulses will allow the pump to “catch up” by producing the correct number of pump strokes
that should have occurred while it was stopped. The 'Over' indicator will light up if the
pump receives pulses while in the 'Stopped' condition (see Figure 8 and the schematic
below).
4
235678
Power Ground
Stop Input
White
NEU Black
HOT Green
3.6 AC Power Interruption
If AC power is interrupted, the pump will power up as shown below:
State preceding power OFF State following power ON
WAIT WAIT
Run Manual Run manual
Run external Run external
Set EXTernal mode WAIT
Set EXTernal values WAIT
17

4.0 MAINTENANCE
CAUTION: Before working on the pump, disconnect the power cord, depressurize the
discharge tubing and drain or flush any residual liquid from the pump head and valves.
Always wear protective gear when working around chemicals.
4.1 Diaphragm Replacement
Disconnect AC power to the pump and disconnect the suction tubing and discharge
tubing. Remove the four head bolts with a 4mm hex wrench. Turn the stroke length knob
fully counter-clockwise. Unscrew the diaphragm and remove its retainer (small disk
behind the diaphragm). CAUTION: There may be small brass spacers between the
retainer and the armature shaft. These spacers need to be re-used when replacing the
diaphragm. Install the new retainer and diaphragm on the shaft. Turn the diaphragm
clockwise until it bottoms on the shaft. Replace the pump head and tighten the head bolts
to a torque of 19 lb-in (2.16 N-m).
4.2 Valve Replacement
Making sure the discharge side has been depressurized, remove the suction and discharge
tubing. Remove the suction fitting, two valve cartridges*, o-ring and gasket(s). Install the
new o-ring, gasket(s) and valve cartridges. Be sure both valve seats are in the same
orientation. Refer to Figure 9 below. Tighten the suction fitting. Similarly remove and
replace the discharge valve cartridges, o-ring and gasket(s).
*EHE45 and EHE55 series have one valve cartridge on the suction and discharge sides.
Refer to Section 5.0 for exploded view drawing and parts list.
FLOW
Valve Guid
e
Ball
Valve Seat
Gasket
Figure 9 Valve Cartridge Orientation
4.3 Tubing
Check ends of tubing for splits, cracks or thin spots. Examine the full length of tubing for
damage due to chafing, abrasion, stress cracks, excessive temperature or exposure to
ultraviolet light (direct sunlight or mercury vapor lamps). If any signs of deterioration
exist, replace the entire length of tubing. It is a good idea to replace discharge tubing on a
regular preventative maintenance schedule every 12 months.
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5.0 EXPLODED VIEW AND PARTS GUIDE
5.1 How to order parts for your metering pump.
Have your catalog or model number ready. This is found
on the silver label on the side of the pump.
From the exploded view drawing, identify the item
number of the part(s) to be ordered.
The item numbers are listed and include part number,
description and size/material information.
Contact your Walchem distributor for further assistance.
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