6.0 System Details
14
© Baxi Heating UK Ltd 2009
6.5
System Controls
This boiler does not require a bypass.
This boiler does not require a permanent live.
The pump only needs wiring directly to the boiler for
fully TRV’d systems.
1. To comply with Part L1 of the Building Regulations the
heating system into which the boiler is installed should
include the following:
a) zone controls
b) timing controls
c) boiler control interlocks
2. Such a system needs to be fully pumped and must
provide independent temperature and time control to
both the heating and hot water circuits and have a boiler
interlock.
3. The boiler should be controlled so that it operates on
demand only. Where it is proposed to effect control by
thermostatic radiator valves, a room thermostat (or
other device such as a flow switch - a flow switch is
integral to this boiler) should also be provided to switch
off the boiler when there is no demand for heating or
hot water.
4. The interlock for the CH circuit can be provided by
either a Room Thermostat or a fully TRV’d system with
the pump wired back to the boiler without a bypass.
Connection diagrams for both options for Y and S plan
systems are shown.
Y Plan
Diverter
Valve
Cylinder
Stat
Room
Stat
Boiler
Pump
Timer
230V
50Hz
L N E
L
N
CH on
HW on
HW off
L
N E
L
N P/F
E
b
g/y
w
o
gr
1
C 2
g/y
S Plan
Valve
Cylinder
Stat
Room
Stat
Boiler
Pump
Timer
230V
50Hz
L N E
L
N
CH on
HW on
L
N E
L
N P/F
E
Motor
S Plan
Valve
Motor
o
o
gr
b
g/y
b
gr
br
br
Y Plan
Diverter
Valve
Cylinder
Stat
Boiler
Pump
Timer
230V
50Hz
L N E
L
N
CH on
HW on
HW off
L
N E
L
N P/F
E
b
g/y
o
gr
1
C 2
w
g/y
S Plan
Valve
Cylinder
Stat
Boiler
Pump
Timer
230V
50Hz
L N E
L
N
CH on
HW on
L
N E
L
N P/F
E
Motor
S Plan
Valve
Motor
o
o
gr
b
g/y
b
gr
br
br
Y Plan, Room Thermostat System, CH Interlocked By Room Thermostat
At least the Radiator(s) near the Room Thermostat not TRV’d
Pump run from Switched Live
By-pass permitted but not required for Part L1 compliance
S Plan, Room Thermostat System, CH Interlocked By Room Thermostat
At least the Radiator(s) near the Room Thermostat not TRV’d
Pump run from Switched Live
By-pass permitted but not required for Part L1 compliance
Y Plan, Fully TRV’d System, CH Interlocked By Boiler Flow Switch
Room Thermostat should not be fitted
Pump must be run from Boiler P/F connection for Part L1 compliance
By-pass not permitted (must be valved off) for Part L1 compliance
S Plan, Fully TRV’d System, CH Interlocked By Boiler Flow Switch
Room Thermostat should not be fitted
Pump must be run from Boiler P/F connection for Part L1 compliance
By-pass not permitted (must be valved off) for Part L1 compliance
Key to colours
b
-
Blue
br
-
Brown
w
-
White
o
-
Orange
gr
-
Grey
g/y -
Green/Yellow