16
Chapter 2. Installation, Wiring
z
Sample countermeasure for power surges caused by lightning
When using a surge absorber as a countermeasure for power surges caused by
lightning, connect it between terminal 3 and ground, as shown below.
The mounting brackets of the surge absorber are electrically connected internally
by crimping to the ground side of the absorber. Therefore, the absorber can be
grounded simply by attaching the brackets to a grounded metal part such as the
combustion equipment housing. For wiring to the power supply, use 0.75 mm
2
or larger wires (diameter: 0.18, strand count: 30), in compliance with JIS C 3306.
Attach a #187 Faston receptacle at one end and keep the wire length as short as
possible.
2
3
Power supply
Surge absorber
83968019-001
Surge absorber
83968019-001
2
3
Power supply
High-voltage side
(L1)
Low-voltage side
(L2(N))
Line surge
absorber
Line surge
absorber
Faston terminal side
(187 series)
Faston terminal side
(187 series)
Mounting bracket side
(ground side)
Mounting bracket side
(ground side)
Bur
ner c
on
tr
oller
Bur
ner c
on
tr
oller
Connections to solenoid valve
CAUTION
Connect the load (ignition transformer, solenoid valve, etc.) directly to the output terminals of
this device. If it is not directly connected, combustion safety cannot be ensured.
z
Operation in case of a ground fault
High-voltage side
(L1)
K1
K2
K3/K4
FB
(Ground fault)
Valve (closed)
Low-voltage side
(L2 (N))
AUR455
Burner Combustion
equipment
If a ground fault occurs in the solenoid valve wiring, since both lines to the solenoid
valve are cut off by the burner controller contacts, the solenoid valve will not
operate. Therefore, since the solenoid valve will not open, there is no risk of fuel
outflow. If the burner controller is started in this state, signal FB in the figure is
detected and lockout occurs due to E904 (voltage generated on terminals 4 and 5).