Emerson Mobrey Hydratect 2462 User manual

Reference Manual
24625020, Rev AA
March 2017
Mobrey™Hydratect 2462
Steam/Water Detection System

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Reference Manual
24625020, Rev AA
Title Page
March 2017
Title Page
Mobrey™Hydratect 2462
Read this manual before working with the product. For personal and system safety, and
for optimum product performance, make sure you thoroughly understand the
contents before installing, using, or maintaining this product.
Failure to follow these guidelines could result in death or serious injury.
Avoid contact with the leads and terminals. High voltage that may be present on leads
can cause electrical shock.
Explosive atmospheres
Never operate the equipment, or any sensors connected to the equipment, in a
potentially explosive atmosphere. It is not intrinsically safe and could possibly cause an
explosion.
Grounding
To minimize the hazard of electrical shock, it is essential that the equipment be
connected to a protective ground (earth) whenever the power supply, measurement,
or control circuits are connected, even if the equipment is switched off.
The electronics unit must be connected to ground (earth) using the marked case stud
before control or signal leads are connected. The ground (earth) connections must
have a current rating of 25 A.
Avoid using unsafe equipment
The equipment may be unsafe if any of the following statements apply:
Equipment shows visible damage.
Equipment has failed to perform an intended operation.
Equipment has been stored in unfavorable conditions.
Equipment has been subjected to severe physical stress.
If in any doubt as to the serviceability of the equipment, do not use it. Get the
equipment properly checked by a qualified service technician.
Live electrical wires
When the equipment is connected to a power supply, the opening of covers or removal
of parts could expose live electrical wires.
The equipment must be disconnected from all power and signal sources before it is
opened for any adjustment, replacement, maintenance, or repair.
Adjustment, maintenance, and repairs must be must be done by qualified personnel.
DO NOT OPEN THE ELECTRONICS UNIT WHEN IT IS ENERGIZED.
Equipment modification
To avoid introducing safety hazards, never install non-standard parts in the equipment,
or make any unauthorized modification. To maintain safety, always return the
equipment to Rosemount Measurement Limited for service and repair.

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The equipment described in this reference manual has been designed in accordance
with EN61010 “Safety requirements for electrical equipment for measurement,control
and laboratory use”, and has been supplied in a safe condition.
The equipment is designed solely for electronic measurement and should be used for
no other purpose. Rosemount Measurement Limited accepts no responsibility for
accidents or damage resulting from failure to comply with these precautions.
Cleaning
To clean the instrument, use a damp cloth with a mild, water-based cleaner. Clean the
exterior of the instrument only. Do not allow liquids to enter or spill onto the
instrument.
Mains ac power supply
Never operate the equipment from a line voltage or frequency in excess of that
specified. Otherwise, the insulation of internal components may break down and cause
excessive leakage currents.
To allow the electronics unit to be isolated from the ac supply, the supply must be
routed through a switch (or circuit breaker). The switch (or circuit breaker) must be
within easy reach of the operator and must be clearly identified as the means of supply
isolation. The maximum current drawn from the supply must be limited by a fuse or
trip, to a maximum of 13 A.
Fuses
Before switching on the equipment, check that the fuses accessible from the interior of
the equipment are of the correct rating. The rating of the ac line fuse must be in
accordance with the voltage of the ac supply.
Should any fuse continually blow, do not insert a fuse of a higher rating. Switch the
equipment off, clearly label it “unserviceable” and inform a service technician.
Not designed for nuclear-qualified applications
The products described in this document are not designed for nuclear-qualified
applications. Using non-nuclear qualified products in applications that require
nuclear-qualified hardware or products may cause inaccurate readings.
For information on Rosemount nuclear-qualified products, contact your local Emerson
Process Management Sales Representative.

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Table of Contents
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Table of Contents
Contents
1Section 1: Introduction
1.1 Using this manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Product recycling/disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 What the Hydratect 2462 does . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3.1 Steam and water detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3.2 Contamination detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3.3 Fail-safe operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 The Hydratect 2462 variants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 Typical applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.5.1 High water level detection in a drain pot . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5.2 Water level detection in a boiler drum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6 How electrodes operate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.6.1 Conductivity and resistance values of steam and water . . . . . . . . . . . . . . . 7
1.6.2 The signal returned by the electrode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.6.3 LED and relay states for electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2Section 2: Installing the electrodes
2.1 Electrode installation methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
2.2 Mounting an electrode to an insert. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
2.2.1 Welding the electrode insert to a pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
2.2.2 Fitting the electrode-insert cover (part one) . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2.3 Fitting the electrode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.2.4 Fitting the electrode-insert cover (part two) . . . . . . . . . . . . . . . . . . . . . . . .16
2.3 Mounting electrodes on a manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
2.4 Customized manifolds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3Section 3: Installing the Electronics Control Unit
3.1 Installation summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
3.2 Fitting cable glands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
3.3 Mounting the Hydratect 2462 Control Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
3.4 Setting the printed circuit board (PCB) jumpers . . . . . . . . . . . . . . . . . . . . . . . . . .23
3.5 Connecting the electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
3.5.1 Preparing the electrode cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.5.2 Preparing the fault and status relay cable
(for the Hydratect 2462A and 2462C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

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3.5.3 Preparing the fault and status relay cables
(for the Hydratect 2462E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
3.5.4 Preparing the power supply cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.5.5 Connecting the prepared cables to the front panel . . . . . . . . . . . . . . . . . . 37
4Section 4: System Testing
4.1 Test summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
4.2 Testing the electrodes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
4.2.1 Suggested test for water-normal setting . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.2.2 Suggested test for steam-normal setting . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5Section 5: Electrodes Servicing
5.1 Service summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
5.1.1 Safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
5.2 Periodic check. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
5.3 Repairing an electrode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
5.4 Periodic system overhaul . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
5.5 Electrode replacement parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
6Section 6: Electronics Servicing
6.1 Fault diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
6.2 Correcting a fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
6.2.1 Correcting a power loss fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6.2.2 Correcting electrode connection faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
6.3 Electrode contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
6.4 Electronic component failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
6.5 Electronic replacement parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
A.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
A.1.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
A.1.2 Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
A.1.3 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
A.1.4 Mechanical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
A.1.5 Environmental. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
A.1.6 Approvals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
A.2 Dimensional drawing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

Reference Manual
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Introduction
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Introduction
Section 1 Introduction
1.1 Using this manual
The sections in this manual provide information on installing, operating, and maintaining
the Mobrey™Hydratect 2462. The sections are organized as follows:
Section 2: Installing the electrodes contains the procedures for mounting electrodes to a
pipe or manifold.
Section 3: Installing the Electronics Control Unit contains the mechanical and electrical
installation procedures.
Section 4: System Testing contains procedures to check the operation of the Hydratect 2462
system after installation completion or any configuration change.
Section 5: Electrodes Servicing describes the electrode servicing procedure that must be
followed to ensure continued and trouble-free operation of the Hydratect 2462 system.
Section 6: Electronics Servicing contains fault-finding and fault-correction procedures for the
electronics control unit.
Section A: Specifications and Data contains specifications and other reference data, including
dimensional drawings.
1.2 Product recycling/disposal
Recycling of equipment and packaging should be taken into consideration and disposed of
in accordance with local and national legislation/regulations.
1.3 What the Hydratect 2462 does
The Hydratect 2462 system is the electronic alternative to conventional water level
switches on steam-raising plant. The system contains a compact, two-channel electronic
control unit connected to a pair of electrodes that are mounted in the plant pipe-work
(See Figure 1-1 on page 2).
Each of the two channels gives independent indications of the presence of water or steam
that are much more reliable than those obtained with conventional electro-mechanical
devices. The electronics control unit provides a local indication of steam, water, and fault
states, and has configurable fault- and trip-outputs.
Typical applications of the Hydratect 2462 system are:
Drain pots.
Water detection in steam lines.
Low- or high-level water detection.
Wherever it is necessary to detect water or steam.

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Figure 1-1. The Hydratect 2462 Electronics Control Unit
A. Wall mounting brackets (lugs). C. Alarm and trip signal output.
B. M6 earthing/grounding stud.
Front view of electronics control unit
B
A
Example of Hydratect 2462 system with the
electronics control unit, and horizontal pipe run
with mounted electrodes and covers.
C

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1.3.1 Steam and water detection
On each of the two electrically-isolated channels, the Hydratect 2462 system detects steam
and water by using the differences in their resistance and conductivity (Figure 1-5 on
page 7).
Detection of steam and water is indicated by the illumination of a red or green LED on the
front panel of the Hydratect 2462 Electronics Control Unit (Figure 1-1 on page 2).
The Hydratect 2462 system also provides status outputs from relays (one per channel) to
indicate the detected states. Each status relay has normally-open and normally-closed
electrical contacts to control external equipment.
Each Hydratect channel is individually set to a water-normal or steam-normal state by using
configuration ‘jumpers’(1) on a printed circuit board (PCB). The ‘jumpers’ must be set to
correspond with the normal state of the system. This allows the status relays to default to
the not-normal state if the Hydratect 2462 system developed a fault. For example, a status
relay is de-energized when a steam-normal channel monitoring a steam line detects water
(i.e. a not-normal state). In that situation, the normally-open relay contacts close and the
normally-closed contacts open. A latch option is available for each status relay, which, once
activated, holds the relay in the not-normal state until reset.
See “Setting the printed circuit board (PCB) jumpers” on page 23 for further information.
1.3.2 Contamination detection
To prevent a build-up of contamination causing a false indication, a contamination
detection circuit operates in parallel with the steam/water detection.
An error threshold for the contamination detection circuit can be set for high sensitivity or
low sensitivity by using ‘jumpers’ on a PCB. The circuit can be switched off if not required.
See “Setting the printed circuit board (PCB) jumpers” on page 23 for further information.
Detected contamination on a Hydratect channel is indicated by the front panel fault LED,
and a fault relay (one per channel) is de-energized for use by external equipment.
1.3.3 Fail-safe operation
For reliability, each Hydratect channel has a separate power supply.
The Hydratect 2462 system continuously monitors itself for component failure, cable faults,
ground (earth) faults, and electrode problems. Components outside the self-monitoring
loop are in triplicate such that if two were to fail, the system would still function normally.
Component failures are indicated by the front panel fault LED and cause the fault and/or
status relays to be de-energized.
Hydratect 2462 system self-checking includes the signal and ground (earth) cable
terminations at the electrodes. The fault LED is illuminated and the fault relay is
de-energized if one or more conductors become detached.
The ways in which the LEDs and relays indicate the system state are summarized in
Table 1-2 and Table 1-3 on page 9.
1. A PCB ‘jumper’ is a metal bridge that closes an electrical circuit. Typically, a ‘jumper’ consists of a plastic plug that fits over a pair of
protruding pins. By placing a jumper plug over a different set of pins, you can change a board's parameters.

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Electrode signals, status outputs (relays), and fault outputs (relays) can be validated by
connecting both Hydratect channels in a 'one-out-of-two' or 'two-out-of-two' tripping
scheme. Typical applications are shown in Figure 1-3 on page 6 and Figure 1-2 on page 5.
Further information is in Section 3: Installing the Electronics Control Unit.
1.4 The Hydratect 2462 variants
The Hydratect 2462 Electronics Control Unit is available in three standard configurations,
as listed in Table 1-1.
Table 1-1. Hydratect 2462 Variants
1.5 Typical applications
1.5.1 High water level detection in a drain pot
Figure 1-2 on page 5 shows a system for detecting a high water level in a drain pot attached
to a superheat steam line. In this system example, a Mobrey In-line Manifold with two
electrodes are used to detect the same level.
The electrode outputs of both Hydratect channels (1 and 2) are connected in a
'one-out-of-two' configuration inside the electronics control unit. Both channels can then
indicate a high water level, providing an element of safety if one of the two electrodes fail.
Model
Supply Relay output
Mains a.c. d.c. SPST relays(1)
1. Single Pole Single Throw (SPST) relays have Normally Open (NO) and Normally Closed (NC) contacts.
DPCO relays(2)
2. Double Pole Change Over (DPCO) relays have two sets of Normally Open (NO), Common (C), and Normally Closed (NC)
contacts.
2462A  
2462C  
2462E   

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Figure 1-2. High Water Level Detection in Drain Pot
A. Superheat steam line. D. Drain line.
B. Drain pot. E. High alarm signal.
C. Isolation valve. F. In-line manifold with two electrodes (channels 1 and 2).
1.5.2 Water level detection in a boiler drum
A Hydratect 2462 system for detecting high and low water levels in a boiler drum is shown
in Figure 1-3 on page 6.
Trip signals are validated by connecting both Hydratect channels using a “two-out-of-two”
configuration in a Hydratect 2462 Electronics Control Unit. For example, the high-level trip
signal occurs only when water is detected at both the high and the high-high water level
electrodes. Further information is in Section 3: Installing the Electronics Control Unit.
The illustrated Hydratect 2462 system uses a sidearm manifold for detecting intermediate
water levels between high and low. Connection information for the manifold pipework is in
Figure 1-4 on page 6.
Note the following points:
The connecting pipework must be sloped as indicated in Figure 1-4 on page 6.
This is done to ensure a flow of condensate through the manifold.
The isolating valves, when opened, should allow unrestricted flow through the
manifold. Globe valves are highly recommended. These valves should be installed
with the handle spindle horizontal.
The connecting pipework must be insulated, as shown by the dashed lines marked
in Figure 1-4 on page 6.
A
B
C
D
C
F
E

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Figure 1-3. Water Level Detection in Boiler Drum
A. High-high level electrode. E. High alarm and trip signal output from Control Unit.
B. High level electrode. F. Low alarm and trip signal output from Control Unit.
C. Low level electrode.
D. Low-low level electrode.
Figure 1-4. Manifold Connection Details
A. Steam connection. D. Drain connection.
B. Water connection. E. Cover mounting blocks (four positions).
C. Hanger for suspending the manifold in position. F. Pipe insulation (shown by dashed outline).
Pipe-run slope gradient (1 in 50 minimum). Installation should follow national and station practice.
A
B
D
E
F
C
6.6 ft. (2 m) maximum
F
A
B
C
D
E

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1.6 How electrodes operate
1.6.1 Conductivity and resistance values of steam and water
Figure 1-5 shows conductivity and resistance values of steam, pure water, and typical boiler
water. The significant difference between the resistance of steam and boiler water allows
the Hydratect 2462 system to differentiate between the two.
An electrode acts as a resistor when inserted into the pipe containing the steam or water.
Resistance values are greater than 10 Mfor steam and between 2 kand 100 kfor boiler
water. In a Hydratect 2462 Electronics Control Unit, the resistance forms the lower half of a
potential divider, across which an alternating driving signal is applied. The signal amplitude
of the potential divider output is high for steam (~±6 V) and low for water (~±3 V).
Two conductivity values, 0.6 S/cm for high sensitivity and 1.6 S/cm for low sensitivity, are
selectable to suit the operating conditions and the purity of the boiler water.
See “Setting the printed circuit board (PCB) jumpers” on page 23 for further information.
Figure 1-5. Conductivity and Resistance of Steam and Water
A. Typical steam values. D. Typical boiler water
B. Hydratect switching band (0.6 S/cm setting). E. Pure water.
C. Hydratect switching band (1.6 S/cm setting).
A
B
C
D
E
Temperature (°C)
200 300 400
0.01
0.1
1
10
100 1
10
100
1000
10000
Conductivity (S/cm)
Resistance (K)

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1.6.2 The signal returned by the electrode
In Figure 1-6, the signal returned by the electrode is proportional to the resistance between
the electrode tip and ground (earth). This signal is used to detect the presence of steam or
water. A signal with a very small amplitude represents a fault e.g. a broken wire or a
short-circuit.
To obtain consistent resistance values, each electrode, and the insert/manifold in which it is
mounted, is designed for a common cell constant of 0.1. This gives a resistance of between
2 kand 100 kfor typical boiler water, and a resistance greater than 10 Mfor steam.
Each electrode connection is terminated individually through a crimped nickel terminal ring
to enable the Hydratect 2462 Electronics Control Unit to detect an open circuit. Details for
the correct connections are given in Section 3: Installing the Electronics Control Unit.
To avoid electrolytic action, the electrode is driven by an alternating signal. The low
frequency of this signal ensures that the signal returned by the electrode is unaffected by
the cable capacitance.
Figure 1-6. Electrode Returned Signal
Hydratect 2462 Electronics Control UnitHydratect 2462 Electronics Control Unit
Drive
resistor Drive (~±6V)
Steam
Water
Signal amplitude proportional
to electrode resistance:
0 V Detection
0 V

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1.6.3 LED and relay states for electrodes
Table 1-2 and Table 1-3 on page 9 summarizes the ways in which the LEDs and relays of
Hydratect reflect the system state for electrodes.
Note
See “Setting the printed circuit board (PCB) jumpers” on page 23 for information on
water-normal and steam-normal settings.
Table 1-2. LED and Relay States for Electrode (Water-Normal Setting)
Table 1-3. LED and Relay States for Electrode (Steam-Normal Setting)
System state Front panel LEDs Relays
!Steam Water Fault Status normal
Electrode in water, no fault Off Off On Energized Energized
Electrode in steam, no fault Off On Off Energized De-energized
Power supply loss Off Off Off De-energized De-energized
Electrode contaminated or short-circuited On Off On De-energized Energized
Connection in electrode sense element is broken On Off On De-energized Energized
Connection in electrode ground is broken On Off On De-energized Energized
Connection to ground sense is broken - electrode in water On Off On De-energized Energized
Connection to ground sense is broken - electrode in steam On On Off De-energized De-energized
System state Front panel LEDs Relays
!Steam Water Fault Status normal
Electrode in steam, no fault Off On Off Energized Energized
Electrode in water, no fault Off Off On Energized De-energized
Power supply loss Off Off Off De-energized De-energized
Electrode contaminated or short-circuited On Off On De-energized De-energized
Connection in electrode sense element is broken On Off On De-energized De-energized
Connection in electrode ground is broken On Off On De-energized De-energized
Connection to ground sense is broken - electrode in water On Off On De-energized De-energized
Connection to ground sense is broken - electrode in steam On On Off De-energized Energized

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Reference Manual
24625020, Rev AA
Installing the electrodes
March 2017
Installing the electrodes
Section 2 Installing the electrodes
2.1 Electrode installation methods
The electrodes available for use with a Hydratect 2462 system are listed in Table 2-1.
For an electrode to function correctly, it must be contained in a 'cell' of known volume.
This allows the Hydratect 2462 Electronics Control Unit to differentiate between the
resistance of a known volume of steam and the same volume of water. For this reason,
electrodes are mounted in an insert or a manifold.
An insert is for the mounting a single electrode in a vertical or horizontal pipe run, but the
manifold is for the mounting of up to four electrodes vertically.
A single Hydratect 2462 system can use one or two electrodes. Where two are used, they
should be spaced apart by a minimum of 3 in. (76 mm) if on the same side of the pipe or
manifold, or 1.5 in. (38 mm) if on opposite sides.
Table 2-1. Available Electrodes
2.2 Mounting an electrode to an insert
Mounting an electrode on an insert involves four steps:
1. Welding the insert to the pipe.
(see “Welding the electrode insert to a pipe” on page 12).
2. Fitting the base plate of an electrode-insert cover
(see “Fitting the electrode-insert cover (part one)” on page 13).
3. Fitting the electrode to the insert (see “Fitting the electrode” on page 15).
4. Fitting an electrode cover
(see “Fitting the electrode-insert cover (part two)” on page 16).
Electrode covers are available which offer a basic level of mechanical and
environmental protection, but have not been assessed to any particular protection
standards.
Emerson recommend that the installer gives particular attention to the location and
environment where the equipment is being installed and, if necessary, fit additional
protective measures.
Part number
Maximum
pressure
Maximum
temperature PH range
Insulation
type
246785Z 210 bar (3045 psi) 370 °C (698 °F) 7 to 11 Zirconia
246785A 300 bar (4350 psi) 560 °C (1040 °F) 7 to 11 ZTA

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Reference Manual
24625020, Rev AA
Installing the electrodes
March 2017
Installing the electrodes
Note
See “Mounting electrodes on a manifold” on page 18 for the alternative mounting method.
2.2.1 Welding the electrode insert to a pipe
Procedure
1. Cut an aperture in the pipe for the electrode insert part number 24673540B.
(Any debris must be removed from the pipe-work before testing the system).
2. Fit the electrode insert into the prepared aperture, ensuring that the orientation
slot is pointing downwards.
Take care not to damage the thread or conical seat on the Series III electrode insert.
The cast/lot number on the insert must not be obscured by welding.
90±5°
1.06 in.
(27 mm)
0.04 in. (1 mm)
nominal
Ø1.5 in. (Ø38.1 mm)
minimum
0.13 to 0.63 in.
(3.4 to 16 mm)
Horizontal pipe run Vertical pipe run

13
Reference Manual
24625020, Rev AA
Installing the electrodes
March 2017
Installing the electrodes
3. Check that the inner edge of the circular groove around the electrode insert body is
level with the bottom of the weld preparation.
4. Weld the electrode insert in place.
The welding procedure must comply with the National or Regional Codes of
Practice for Joining Dissimilar Metals.
5. Repeat steps 1 to 4 for the second insert, if required. Electrodes should be spaced
apart by a minimum of 3 in. (76 mm).
2.2.2 Fitting the electrode-insert cover (part one)
Part one of the cover fitting procedure
1. Dismantle the electrode-insert cover assembly (part number 24670118A) into its
component parts (see Figure 2-1 on page 14).
2. Screw the base plate to the electrode insert, and tighten it with a strap wrench
(see Figure 2-2 on page 14).
After part one is completed, install the electrode (see “Fitting the electrode” on page 15)
and complete cover fitting (see “Fitting the electrode-insert cover (part two)” on page 16).
Horizontal pipe run
Weld preparation
0.28 in. (7 mm)

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Reference Manual
24625020, Rev AA
Installing the electrodes
March 2017
Installing the electrodes
Figure 2-1. Individual Electrode-insert Cover Assembly of Component Parts
A. Top plate (complete with securing studs, washers, and nuts).
B. Cylindrical housing (complete with cable gland).
C. Base plate (complete with two pairs of earthing/grounding screws and washers).
Figure 2-2. Base Plate Fitting
A. Base plate (complete with two pairs of earthing/grounding screws and washers).
B. Electrode insert, with orientation slot pointing downwards, welded to a pipe run.
C. Horizontal pipe run.
D. Vertical pipe run.
The base plate is screwed into the insert on the same thread used for the electrode fixing nut.
A
B
C
A
B
C
D
B