Installation
37
MAXXflo EVO
4.10 ELECTRICAL & COMMuNICATION CONNECTIONS
DANGER
This heater must be earthed
DANGER
Isolate the mains electrical supply to the heater before starting any work and observe all relevant
safety precautions
External wiring to the heater must be installed in accordance with current Regulations for the wiring
of buildings and to any Local Regulations that may apply.
This heater is designed to operate from a 230V, single phase supply fused at 5 amps. Mains input cable should
be at least 0.75mm
2
, 3 core cable.
The method of connection to the mains electricity supply should facilitate complete electrical isolation of the
heater. A fused double pole switch or fused spur box serving only the heater should be used. The point of con
-
nection and isolation to the mains electricity supply should be readily accessible and adjacent to the heater, and
should be connected to the mains supply as detailed above.
4.10.1 ACCESS TO THE TERMINAL CONNECTIONS
Open the heater front door panel by removing the two screws on the left hand side, to reveal the electrical con
-
nections inside (see illustration below).
4.10.2 VOLT FREE CONNECTIONS
This heater has volt free connections, which can be used for a Building Management System or a remote indica
-
tor panel. These volt free connections are pre-configured to perform the following functions:
Volt free - Remote enable -
Closing this connection will activate the DHW system
Volt Free - Fault Indicator
-
Immediately after a fault or maintenance warning has been detected by the control
system, an internal relay will activate and close the circuit to indicate that a fault has occurred. In order to avoid
temporary or short acting faults, a 1 minute delay before the fault is reported by the heater is factory set. This can
be changed via parameter 6612, accessible using the GUI screen.
Volt Free - Flame Indicator
- When any of the heat engines are in operation, an internal relay will activate and
close the circuit to indicate that at least one heat engine is in operation.
Wiring diagram - MAXXflo EVO
Master (Models 90 & 120 kW)
H2 M
BX
21
BX
22 U+
M
M
od
ule
N
o1
L
N QX
23
QX
22
QX
21
N
N
Re
m
ot
e
en
ab
le
(v
olt
fr
ee
)
Fl
am
e
ind
ica
to
r 1
Q4
DHW
pump
Fa
ult
in
dic
at
or
Liv
e
Ne
ut
ra
l
Liv
e
Earth
Ne
ut
ra
l
B39
DHW
Return
sensor
kit
Fl
ame
ind
ica
to
r 2
Bl
ac
k
Re
lay
White Re
lay
Modbus
L N PE L N
230V
50Hz
5A
BSB
A+ B-
RE
F
DB
/C
L+
MB
/C
L-
1 2 3 4
9
5 6 7 8
Bl
ac
k
Re
lay
CO
NO
NC
CO
NO
NC
CO
NO
NC
Low / No voltage
High voltage
