10
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Explanation of operation
• Normal operation and shutdown
Chapter 2. MOUNTING AND WIRING
No
Input status
FRS100 activity
Output activity
1
Power ON
Receives power across terminals 1 and 2.
(POWER LED lights up)
2
Blower operation
If the limit switch and interlock status is normal,
the blower starts. After completion of the prepurge,
the prepurge completion signal is transmitted to
allow execution of the next operation.
3
Burner start
If the limit switch and interlock status is normal
(Start check operation LED
contacts ON
(limit switch contacts closed), when the burner
lights up)
start contacts are closed, power is applied across
terminals 7 and 2. Relay 1K turns on after
completion of the start check.
4
Ignition switch ON
When the ignition switch is pushed (contacts closed), • Ignition transformer ON
power is applied from terminal 8 to the pilot valve
• Pilot valve opens
and ignition transformer. The ignition transformer
• Combustion lamp lights
turns on, the pilot valve opens, and the combustion up
lamp lights up.
The flame detector detects the pilot burner flame,
• (FLAME LED lights up)
and relay 2K turns on, allowing power to be
supplied through terminal 4.
5
Ignition switch OFF Since the ignition switch contacts are open, power • Ignition transformer OFF
to the ignition transformer is cut, and ignition
• Pilot valve continues
transformer operation stops.
open
Because power is supplied through relays 1K and • Main valve opens
2K, power through terminal 4 continues to maintain
the operation of the pilot valve. When the ignition
switch is turned off, its N.C. contacts close, supply-
ing power to the main valve, which opens.
6
Blower stop
Since the prepurge completion signal has been
• Pilot valve closes
discontinued, the power across terminals 7 and 2
• Main valve closes
is cut, relay 1K turns off, and the power to terminal
(FLAME LED turns off)
4 is also cut. The pilot and main valves close, and • Combustion lamp turns
the combustion lamp turns off.
off
All loads are de-energized, and when the flame
• (Start check operation
detector detects the flame failure, relay 2K turns off.
LED turns off)
The FRS100 returns to standby status and waits
for the next start signal.
Limit/Interlock contacts
(1)Power ON
(3)Burner start contacts ON
(4)Ignition switch ON
Flame detection
Start check (2s)
Blower operation
Prepurge
Prepurge completion signal
(5)Ignition switch
OFF (5-10s)
(6)Blower stop
(2)Blower operation
Elapsed time
Ignition transformer
Pilot valve
Combustion lamp
POWER LED
FLAME LED
Start check LED
Main valve
Burner start contacts (term.7-2)
Note: It is possible that relay 2K may turn ON when the power is turned on.
