Sentinel SCU User manual

INSTRUCTION MANUAL
Sentinel Corrosion Monitor SCU
04/2019
SCM SCU Instructions V1 0419

2
■ TABLE OF CONTENTS
1 LIST WITH ABBREVIATIONS 3
2 SYMBOLS 3
3 GENERAL DESCRIPTION 4
4 CONTENTS IN THE PACKAGE 5
5 APPLICATIONS 6
6 INSTALLATION 7
7 ACTIVATION 11
8 OPERATION / USE 13
9 READING 14
10 REPLACEMENT 15
11 DISMANTLING 15
12 REMARK 16
13 TECHNICAL DATA 16
13.1 FUNCTIONAL 16
13.2 MAINS ADAPTER 16
13.3 SENSOR 17
13.4 DIMENSIONS / WEIGHT 17
14 ACCESSORIES 18
14.1 USB CABLE 18
14.2 RETRACTOR 18
15 DECLARATION OF CONFORMITY 19

3
■ 1 LIST WITH ABBREVIATIONS
HVAC Heating, Ventilation, Air-conditioning and Cooling
USB Universal Serial Bus
LED Light Emitting Diode
PC Personal Computer
VAC Volts Alternating Current
VDC Volts Direct Current
(m)A (Milli)amperes
mm Millimetre
CE European Conformity
(in accordance with the European legislation)
EMC Electromagnetic Compatibility
RoHS Restriction of Hazardous Substances
Rc Radius of Curvature
Hz Hertz
W Watt
RH Relative Humidity
■ 2 SYMBOLS
Warning about bodily harm/injury
CAUTION! Warning about poor operation and/or damage to
equipment
NOTE Tips for easier use

4
■ 3 GENERAL DESCRIPTION
Sentinel Corrosion Monitor SCU is a patented measuring instrument that
monitors the durability of your heating system in a reliable manner by
providing timely warning of internal corrosion (or the formation of rust),
and also of the particularly harmful eects that may be caused by such
corrosion.
The corrosion monitor therefore can help to prevent unwanted problems,
such as the break-down of boilers and pumps, seized valves, leaks and
blockages caused by poor water quality. Use of the monitor may lead to
prolonged service life for your heating system, higher living comfort, less
unwanted costs and signicant savings of energy and materials.
The sensor consists of two components: a probe and a data logger. By
means of the threaded connection, the probe is mounted perpendicular to
the pipe, with the tip in the water ow. The oxidation of a small piece of metal
in the probe is representative of the general corrosion within the system.
The sensor records the rate of corrosion and warns if the rate becomes
unacceptable or the sensor requires attention.

5
■ 4 CONTENTS IN THE PACKAGE
• Probe with protective cap
• Threaded connection
• Data logger + Quick Guide
• Mains adapter
• 2x Tie wraps (colson strips)
• Instruction Manual
• Assembly guide

6
■ 5 APPLICATIONS
Sentinel Corrosion Monitor SCU is a corrosion sensor for water-based
thermal systems. Studies on corrosion processes in heating systems reveal
that corrosion is a complex phenomenon that is aected by many factors.
The presence of oxygen in the system water is the main cause of general
corrosion in a system. The corrosion monitor is based on an innovative and
patented technology that measures this general corrosion directly.
The major sources of oxygen in the system water are the following:
(see also the European standard EN14868)
• oxygen in the lling water (~10 mg/l) during the initial lling;
• oxygen ingress due to negative pressure zones in the system, caused by
inadequate pressure maintenance (expansion system);
• oxygen ingress due to diusion through materials that are not oxygen-
tight (synthetic pipes, rubber hoses, membranes of expansion tanks,
etc.);
• oxygen in the extra lling water through topping up
(~10 mg/l);
• oxygen in the trapped air due to insucient venting of the system during
initial lling;
• constant equilibration with atmospheric oxygen in open systems.
It is important that chemical treatment in systems is regularly checked
and properly maintained to ensure adequate system protection from scale
and corrosion. In larger systems or those treated with chemical inhibitors,
additional monitors at dierent locations on the system can improve
measurement accuracy.

7
■ 6 INSTALLATION
PREPARATION
1. The sensor is should be installed in the return section of the system, at a
location with adequate ow. The tip of the probe must be placed entirely
in the ow. The installation location must be free of pressure during the
initial installation.
2. Select a location with sucient space around it in order to be able to use
the Retractor to replace the probe under pressure when necessary.
(Fig. 1)
3. Avoid placing the sensor in direct sunlight. (Fig. 2)
(Fig. 2)
(Fig. 1)

8
4. The sensor can be installed by one of three procedures:
In all cases a female G1/2 or Rc1/2 thread is required
a. in an existing socket with a length of max. 25 mm
b. in a T-piece (Fig. 3)
c. in a welding sleeve with a length of max. 25 mm
(probe tip must be well within the ow).
CAUTION! Fittings with a reduced bore or collar could narrow the
threaded connection due to radial compression, and this in turn could
block the probe tip in the t, which has now become too narrow, and
cause irreparable damage.
INSTALLATION
To provide protection against corrosion and limescale, cleaning and
ushing of the system followed by chemical addition of inhibitor should be
considered. Major boiler manufacturers recommend that once cleaned,
commercial heating and closed cooling systems should be dosed with
Sentinel X100 Inhibitor. Prior to adding X100, the system should be cleaned
with either X400 High Performance Cleaner or X800 Fast Acting Cleaner.
More information on these products can be found at:
https://www.sentinelprotects.com/uk/products/commercial/central-
heating-systems
1. Screw the threaded connection tight. Use a suitable sealant. (Fig. 3)
CAUTION! Hand-tighten this threaded connection loosely and
then tighten another quarter turn using a wrench. The connection
should not be forced. If tightened with too much force, the threaded
connection could be narrowed due to radial compression, and this,
in turn, could block the probe tip in the t that has now become too
narrow, and cause irreparable damage.
(Fig. 3)

9
2. Remove the protective cap from the probe. (Fig. 4)
CAUTION! The probe tip should not be damaged.
3. Measure the mounting depth as shown in Fig. 5. Mark this distance on
the probe.
CAUTION! The probe tip must be well within the ow.
4. Screw the probe into the threaded connection to the correct depth, as
marked.
(Fig. 4)
+/- 5mm
(Fig. 5)

10
CAUTION! Do not use sealant (ax, Loctite, etc.). The double
O-rings of the probe are an eective seal. (Fig. 6) The screw thread
serves to ensure that the correct mounting depth for the sensor is
reached. The screw thread must never be damaged. Do not scratch!
5. Click the data logger rmly onto the probe (only one position is possible).
(Fig. 7) Position the data logger as shown in Fig. 8 to protect the connectors
and control button from spray water.
CAUTION! Verify that the data logger has been pushed far enough over
the probe (O-ring of the probe should be fully inside the collar of the
logger). However, never use the logger to screw the probe in or out.
CAUTION! The USB connector between data logger and probe cannot
be used to read data.
(Fig. 8)
(Fig. 6)
(Fig. 7)