20
■
Wiring the solenoid valve
●
Correct connection
Ground current will not flow to the solenoid valve if the valve is wired as shown in
the figure above, even if faulty insulation on the high potential (H) causes a ground
fault. Accordingly, the valve will not open, eliminating the risk of fuel discharge.
●
Wrong connection
Ground current will flow to the solenoid valve if the valve is wired as shown in the
figure above and if a ground fault occurs. Accordingly, the solenoid valve will open
regardless of the flame relay, causing fuel discharge.
Chapter 2. MOUNTING AND WIRING
CAUTION
Do not connect a solenoid valve to the high potential of the circuit. If a ground
fault occurs, the ground fault current may energize and open the solenoid
valve. This device will not be able to prevent the valve from opening and fuel
from flowing out.
High potential (H)
Low potential (G)
(Ground fault)
Burner
Combustion unit
Power
100 V
FRS100
Valve (closed)
Fuel
N
L
(Ground fault)
100 V
Valve (open)
Fuel
N
L
Power
FRS100
High potential (H)
Low potential (G)
Burner
Combustion unit
