Heatrae Sadia FBM 25 ECO 3KW, Installation, Operation And Maintenance Manual, Page: 10 / 40

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the heater returns to the correct level in a controlled
manner.
4.2.3 Electronic Control
All heater functionality is controlled electronically which
allows the following additional features to be supported:
`
Automatic Water Level Control
`
Digital temperature readout display using a Liquid
Crystal Display, LCD
`
Real-time user access to the heater for setup and
adjustment
`
Automatic Pasteurization Control
`
Error Indication using the LCD
`
Building Management System (BMS), interface
allowing remote connectivity to the heater through
volts free connections.
4.2.3.1 Water Level
In normal operation the water heater manages the
level of the stored water inside the unit automatically,
maintaining the correct level and ensuring optimum
performance from the heater. In the unlikely event of a
system failure, the heater has safety features to ensure
that it s huts down in a safe manner, see troubleshooting
section on page 26.
4.2.3.2 User Interface
An LCD display is fitted to the water heater to provide
real time indication of the stored water temperature
inside the unit. In addition, the user interface provides
a visual indication of ‘power on’ and ‘heater on’ via two
red indicators.
The Power On light indicates that mains, 230V ac
power is applied to the unit and that care should be
taken. However this is not proof of isolation, see page
5 for more safety information.
Heater On indicates that the immersion heater is
turned on and will heat the stored water to the required
set point. In addition the user interface has two control
buttons, these allow the heater to be put into manual
mode and the stored water set point to be adjusted to
the required level, see temperature adjustment section
on page 20. This user interface provides the end user,
support en gineer or commissioning engineer with a
clear visual indication of the heater status and allows
adjustment of the water temperature set point. The LCD
provides additional information, see section 4.2.3.4.
4.2.3.3 Auto Pasteurization
WARNING
`
The stored water temperature during
this function exceeds that which is
safe for hand wash requirements, if
the stored hot water is used for hand
washing then an appropriate water
tempering device must be fitted at the
point of use.
WARNING
`
With the addition of this feature,
the obligation to control Legionella
under the provisions laid down by L8,
Legionnaires’ disease: The control
of legionella bacteria water systems.
Approved Code of Practice and
guidance, within the hot water supply
network pipe work are not negated. It is
still the responsibility of the end user or
contracted support agency to manage
this requirement.
The water heater will automatically heat the stored water
temperature to 60°C for one hour should the stored
water set point temperature be inadvertently set to 55°C
or less for a period of 23 hours. This pasteurization
function ensures that the risk of developing Legionella
within the water heater is minimized.
4.2.3.4 Fault Condition Indication
In the unlikely event that a fault with the water heater
develops an error code is displayed in the LCD display.
This is intended to aid fault analysis and helps to reduce
the heater downtime whilst the fault is analysed. See
the troubleshooting section of this document for further
information. One of six error codes will be displayed in
the LCD should a fault develop, see page 27.
4.2.3.5 Building Management
The water heater has electronic hardware that will
allow the unit to interface with Building Management
Systems that are hard wired.

Interconnection with wireless systems is not
possible.
Supplied with the heater is a six way terminal block that
will allow the heater to be hard wired to the Building
Management System through a ‘Volts Free’ connection.
See the heater wiring diagram for wiring connections
on page 8. The interface will allow two input signals to
control the immersion heater to turn it remotely either
on or off and an output signal line providing status of
the heater, fully operational or in fault condition.
4.3 Standard delivery
The units are supplied to site in one package. Within
the box there will be a set of fitting instructions wall
mounting and fixing brackets, heater assembly and
breather pipe assembly.