OMEGA PH-2720-PA pH/ORP Preamplifier Instructions
SAFETY INSTRUCTIONS FOR IN-LINE ELECTRODE INSTALLATION
1.
2.
3.
4.
Do not remove from pressurized lines.
Do not exceed maximum temperature/pressure specifications.
Wear safety goggles or face shield during installation/service.
Do not alter product construction.
Failure to follow safety instructions may result in severe personal injury!
1. Wiring
Preamplifier:
PH-2720-PA
Preamplifier:
PH-2720-PA
Silver (earth ground)
Brown
Blue
Silver (earth ground)
Brown
Blue
(mV Input)
(Iso. Gnd)
(V-)
(mV Input)
(Iso. Gnd)
(T+)
7
6
8
4
10
ALARM
2
ALARM
1
pH
2
12
14
Black
Red
Green
White
Red
0
(V+)
(T-)
ENTER
Green
White
(T+)
(V+)
Black
(T-)
OMEGA
PHCN-5700
OMEGA
PHCN-5700
(V-)
pH
ORP
pH
ORP
Electrodes:
PHE-3271
PHE-2716
Electrodes:
ORE-2715
ORE-2717
Electrodes:
ORE-2715
ORE-2717
Electrodes:
PHE-3271
PHE-2716
Preamplifier:
PH-2720-PA
Preamplifier:
PH-2720-PA
Silver (earth ground)
Silver (earth ground)
Red
Black
Red
Black
(#10) V+
(#11) V-
N/C
(#10) V+
(#11) V-
(#12) T+
(#13) Ain
(#14) ISO
(#14) ISO
pH CONTROLLER
ORP CONTROLLER
RLY
RLY
RLY
RLY
1
2
3
4
RLY
RLY
RLY
RLY
1
2
3
4
Green
Green
mV
ORP
mV
pH
ENTER
CAL
MOD
ENTER
CAL
MOD
White
Brown
Blue
Brown
White
Blue
N/C
TEMP
RELAY
OUTPUT
RELAY
OUTPUT
(#13) Ain
(#14) ISO
OMEGA
PHCN-90
OMEGA
ORCN-90
• Use X1 gain selection
• Use X1 gain selection
pH
ORP
Electrodes:
PHE-3271
PHE-2716
Electrodes:
ORE-2715
ORE-2717
Technical Notes:
• Use 6-conductor shielded cable for cable extensions to 120 m (400 ft)
• Shield must be maintained through cable splice
2. Installation Fittings
Type
Description
Type
Description
Plastic tees
• 0.5 to 4 in.
• PVC or CPVC
Carbon steel
weld-on
• 2 to 4 in, use 1-7/16 in. hole in pipe
• Remove insert before welding
• Mounts via glue-on fittings
weldolets
• Installed by certified welder only
Carbon steel
threaded tees
PVC glue-on
saddles
(O-ring not
required)
• 2 to 4 in., use 1-7/16 in. hole in pipe
• Align wedge arrows with saddle
arrows during assembly.
• 0.5 to 2 in.
• Mounts on threaded pipe ends
Universal
pipe adapter
for large pipes
• For existing pipe fittings 2 in. and up
• External 1-1/4 inch NPT male threads
Iron
strap-on
saddles
• 2 to 4 in., use 1-7/16 in. hole in pipe
Consult OMEGA for additional fitting information.
3. Recommended Position
Customer supplied:
• 3/4 in. NPT threaded
pipe (A)
Customer supplied:
• 3/4 in. NPT nipple (male)
• J-box
C.
D.
3/4 in. NPT OR
ISO 7/1-Rc 3/4
female threads
• J-box (B)
B.
B.
A.
• Flex conduit (C)
• Quick release pipe
clamp (D)
• flex conduit
C.
A.
• Tank flange (E)
0°
E.
2 in.
min.
In-Line
Process
pipe
Open
tanks
Closed
tanks
• Vertical (0°) position optimum
• 4 fps or less for max. performance and sensor life
Caution: If liquid level is not constant, always ensure
liquid contact with electrode tip
4. Installation
Submersible Applications
In-line Applications
2
1
2
1
Sealant
Preamplifier
Preamplifier
Customer
supplied
pipe
3/4 in. NPT or
ISO 7/1-Rc 3/4
A. O-ring lubricant
recommended
(factory applied)
A. O-ring lubricant
Sealant
C.
recommended
B. Align
marks
B. Align
marks
C.
Hand
tighten
only!
(factory applied)
PH-31542-TC Sensor Cap
(purchased separately)
Fitting
inlet
3
Fill with
3 to 4 in.
of sealant
Attach 3/4 in. watertight pipe to the top of the preamplifier. Secure
the threaded connection to prevent any leakage. For additional
defense against possible accumulation of condensation at the back
seal area of the sensor, fill the lower 3-4 inches (75-100 mm) of
conduit or extension pipe with a flexible sealant such as silicone.
5. Accessories
Part no.
Description
Material
PP
Sensor
cap
PH-31542-TC
CAUTION!
FPP-1220-0021
FPP-1224-0021
FPP-1228-0021
Sensor O-ring,
2 required
Viton®
EPR
Kalrez
When replacing O-rings, apply O-ring lubricant to sensor O-rings
prior to preamplifier/electrode assembly. Unlubricated O-rings
may score the preamplifier sealing surface.
6. Specifications
PH-2720-PA pH/ORP Preamplifier
PHE Series pH Electrodes - ORE Series ORP Electrodes
Housing material:
CPVC
Compatible sensors: PHE-3271
PHE-2716
Flat Surface pH Electrode
Bulb pH Electrode
Flat Surface ORP Electrode
Bulb ORP Electrode
General Specifications
Wetted parts:
Sensor body:
O-rings:
ORE-2715
CPVC
Viton®
ORE-2717
Input Impedance:
Operating temp.:
Gain:
>1011
Ω
Electrode junction:
Quality standard:
Porous UHMW polyethylene
CE
0 to 80 °C
X1 (unity)
±4.5 to ±8 VDC, dual supply
Input power:
Maximum pressure/temperature ratings:
• 7 bar (100 psi) max. @ ≤65 °C (149 °F)
• 4 bar (58 psi) max. @ ≤85 °C (185 °F)
Current consumption: <1 mA, dual supply
Quality standard:
CE
BAR
PSI
7 100
5
75
50
25
3
2
Dimensions:
167 212
77 122
25 50
°F
°C
3/4 in. NPT
100
75
female threads
Std.15 ft/
4.6 m cable
SAFETY INSTRUCTIONS FOR IN-LINE ELEC-
TRODE INSTALLATION
1. Do not remove from pressurized lines.
2. Do not exceed maximum temperature/pressure
specifications.
3.6 in./
91 mm
3. Do not install/service without following
installation instructions (see sensor manual).
4. Wear safety goggles and faceshield during
installation/service.
5. Do not alter product construction.
6. Failure to follow safety instructions could result
in severe personal injury!
1.8 in./
46 mm
7. Preamplifier Troubleshooting
Procedure:
A. Install sensor adapter into preamplifier
Simulator
Actual displayed
mV
________________________
________________________
________________________
________________________
B. With preamplifier and instrument connected, simulate pH 4, 7, and
10 and record displayed mV readings (right) and approximate
preamplifier response time between simulations.
Input
4.00, +177 mV
7.00, 0 mV
C. Refer to table on next page for preamplifier troubleshooting tips.
10.00, -177 mV
Preamplfier response time:
With simulator
connected
Error Condition
Possible Cause
Possible Remedy
A) mV output stuck at
zero
B) mV output erratic
C) mV output stuck at
1.4 VDC
A) Shorted input signal
B) Faulty preamplifier or wiring
C) Faulty preamplifier
A) Check preamplifier cable connections and shielding.
B) Verify preamplifier shield connections. Verify cable shield
wire has been maintained through each cable splice.
C) Replace preamplifier
Ok with
A) mV output stuck
near zero
B) mV output erratic
C) Output stuck at
1.4 VDC
A) Cracked electrode glass
B1) Poor contact between
electrode and preamplifier
connectors
A) Replace electrode
B1) Check contacts between electrode and preamplifier.
Contacts must be clean and dry.
B2) Clean electrode, see electrode manual
B3) Isolate electrode in test beaker. If output is stable, ground
loops may exist causing erratic behavior; isolate instrument
outputs (i.e. 4 to 20 mA, 0 to 5 VDC).
C) Replace preamplifier
simulator
connected but
fails with
electrode
B2) Fouled electrode
reference or aged electrode
B3) Ground loop
C) Faulty preamplifier
8. Electrode Maintenance and Cleaning
8.1 Maintenance
•
•
•
Hard coatings: can be chemically removed. Always use the least
harsh chemical which will remove the contaminant within two (2)
minutes without attacking the materials of construction. e.g. calcium
carbonate may be removed with a 5% HCL (muriatic acid) solution.
Variables can affect long term pH or ORP electrode life. For this
reason, a maintenance log is recommended for trend analysis. When
storing boxed sensors, lay the sensor flat to maximize hydration of the
glass surface. Keep the glass surface wet at all times. Soak the sensor
tip in pH 4.0 buffer during system maintenance intervals. In-line
applications should be plumbed with a depression (trap) which ensures
liquid is maintained around the sensor tip. If sensor dehydration has
occurred, soak the sensor tip in pH 4 buffer for 24 to 48 hours, then
visually inspect the electrode for surface cracks, swelling, or
discoloration.
Oily or Organic Coatings: can be removed with detergents or an
appropriate solvent that does not attack the materials of
construction e.g. isopropyl alcohol may be used but acetone must
be avoided to prevent damage to the CPVC sensor body.
ORP electrode surface (platinum rod): can be gently sanded with
600 grit wet and dry silicone or carbide sandpaper, jewelers
rouge, crocus cloth, or very fine steel wool.
8.2 Cleaning
Cleaning techniques vary depending on the type of coating present on
the glass electrode surface or reference junction.
•
Soft coatings: can be removed by vigorous stirring, or with
directed spray of an applicable detergent or solvent onto the glass
electrode surface. Chlorine bleach or mild detergent may be used
to remove soft coatings. Always rinse electrode tip in clean water
after cleaning.
WARNING!
When using chemicals or solvents care should be taken and
appropriate eye, face, hand, body, and/or respiratory
protection should be used.
WARRANTY/DISCLAIMER
OMEGA ENGINEERING, INC. warrants this unit to be free of defects in materials and workmanship for a
period of 13 months from date of purchase. OMEGA’s WARRANTY adds an additional one (1) month
grace period to the normal one (1) year product warranty to cover handling and shipping time. This
ensures that OMEGA’s customers receive maximum coverage on each product.
If the unit malfunctions, it must be returned to the factory for evaluation. OMEGA’s Customer Service
Department will issue an Authorized Return (AR) number immediately upon phone or written request.
Upon examination by OMEGA, if the unit is found to be defective, it will be repaired or replaced at no
charge. OMEGA’s WARRANTY does not apply to defects resulting from any action of the purchaser,
including but not limited to mishandling, improper interfacing, operation outside of design limits,
improper repair, or unauthorized modification. This WARRANTY is VOID if the unit shows evidence of
having been tampered with or shows evidence of having been damaged as a result of excessive corrosion;
or current, heat, moisture or vibration; improper specification; misapplication; misuse or other operating
conditions outside of OMEGA’s control. Components which wear are not warranted, including but not
limited to contact points, fuses, and triacs.
OMEGA is pleased to offer suggestions on the use of its various products. However,
OMEGA neither assumes responsibility for any omissions or errors nor assumes liability for any
damages that result from the use of its products in accordance with information provided
by OMEGA, either verbal or written. OMEGA warrants only that the parts manufactured by it
will be as specified and free of defects. OMEGA MAKES NO OTHER WARRANTIES OR
REPRESENTATIONS OF ANY KIND WHATSOEVER, EXPRESS OR IMPLIED, EXCEPT THAT OF
TITLE, AND ALL IMPLIED WARRANTIES INCLUDING ANY WARRANTY OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. LIMITATION OF
LIABILITY: The remedies of purchaser set forth herein are exclusive, and the total liability of
OMEGA with respect to this order, whether based on contract, warranty, negligence,
indemnification, strict liability or otherwise, shall not exceed the purchase price of the
component upon which liability is based. In no event shall OMEGA be liable for
consequential, incidental or special damages.
CONDITIONS: Equipment sold by OMEGA is not intended to be used, nor shall it be used: (1) as a “Basic
Component” under 10 CFR 21 (NRC), used in or with any nuclear installation or activity; or (2) in medical
applications or used on humans. Should any Product(s) be used in or with any nuclear installation or
activity, medical application, used on humans, or misused in any way, OMEGA assumes no responsibility
as set forth in our basic WARRANTY / DISCLAIMER language, and, additionally, purchaser will indemnify
OMEGA and hold OMEGA harmless from any liability or damage whatsoever arising out of the use of the
Product(s) in such a manner.
RETURN REQUESTS/INQUIRIES
Direct all warranty and repair requests/inquiries to the OMEGA Customer Service Department. BEFORE
RETURNING ANY PRODUCT(S) TO OMEGA, PURCHASER MUST OBTAIN AN AUTHORIZED RETURN
(AR) NUMBER FROM OMEGA’S CUSTOMER SERVICE DEPARTMENT (IN ORDER TO AVOID
PROCESSING DELAYS). The assigned AR number should then be marked on the outside of the return
package and on any correspondence.
The purchaser is responsible for shipping charges, freight, insurance and proper packaging to prevent
breakage in transit.
FOR WARRANTY RETURNS, please have the
following information available BEFORE
contacting OMEGA:
FOR NON-WARRANTY REPAIRS, consult OMEGA
for current repair charges. Have the following
information available BEFORE contacting OMEGA:
1. Purchase Order number to cover the COST of
the repair,
2. Model and serial number of the product, and
3. Repair instructions and/or specific problems
relative to the product.
1. Purchase Order number under which the
product was PURCHASED,
2. Model and serial number of the product under
warranty, and
3. Repair instructions and/or specific problems
relative to the product.
OMEGA’s policy is to make running changes, not model changes, whenever an improvement is possible. This affords
our customers the latest in technology and engineering.
OMEGA is a registered trademark of OMEGA ENGINEERING, INC.
© Copyright 2000 OMEGA ENGINEERING, INC. All rights reserved. This document may not be copied, photocopied,
reproduced, translated, or reduced to any electronic medium or machine-readable form, in whole or in part, without the
prior written consent of OMEGA ENGINEERING, INC.
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6-2720.090-OM/(B-11/01)
M-2035/1101
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