Weil-McLain NX - Manual (Page 11)

WM 550-141-996/1105 Page 11
RWB 6104WMNX R1005
G
R
R
BK
W
O
V
BL/W
BURNER
JUNCTION BOX
BURNER PRIMARY
CONTROL
3/T
T
CAD
CELL
IGNITOR
SOLENOID
VALVE
Y
Y
W
W
W
LIMIT
L1
L2
L2
L2
L2
VALVE
IGNITOR
MOTOR
W
BK
R7184P Primary ontrol C
T
1
2
B ER
MOTOR
URN
R
BK
W
PRESSURE SWITCH
(DIRECT VENT ONLY)
Burners with Beckett Clean Cut Pump must be used with a primary
control that has a valve-on delay (pre-purge). Controls shown have
valve on delay (see control manufacturer’s instructions for timings.)
Electrical shock hazard — can cause severe injury or death. Disconnect
power before installing or servicing.
120 VAC FIELD WIRING
LOW VOLTAGE FACTORY WIRING
120 VAC FACTORY WIRING
LOW VOLTAGE FIELD WIRING
SEE
BOILER
INSTRUCTION
MANUAL
FOR
CORRECT
WIRING
BURNER DISCONNECTS
120 VAC FIELD WIRING
LOW VOLTAGE FACTORY WIRING
120 VAC FACTORY WIRING
LOW VOLTAGE FIELD WIRING
Figure 4. – Typical Burner Wiring & Burner Sequence of Operation
1. STANDBY. The burner is idle, waiting for a call for
heat. When a call for heat is initiated, there is a 2-6
second delay while the control performs a safe start
check.
2. VALVE-ON DELAY. The ignition and motor are
turned on for a 15 second valve-on delay.
3. TRIAL FOR IGNITION (TFI). The fuel valve is
opened. A fl ame should be established within the
15 second lockout time.
4. LOCKOUT. If fl ame is not sensed by the end of
the TFI, the control shuts down on safety lockout
and must be manually reset. If the control locks out
three times in a row, the control enters restricted
lockout.
5. IGNITION CARRYOVER. Once fl ame is estab-
lished, the ignition remains on for 10 seconds to
ensure fl ame stability before turning off. If the con-
trol is wired for intermittent duty ignition, the ignition
unit stays on the entire time the motor is running.
6. RUN. The burner runs until the call for heat is sati-
fi ed. The burner is then sent to burner motor off
delay, if applicable, or it is shut down and sent to
standby.
7. RECYCLE. If the fl ame is lost while the burner is
fi ring, the control shuts down the burner, enters a 60
second recycle delay, and then repeats the above
ignition sequence. If fl ame is lost three times in a
row, the control locks out to prevent cycling with
repetitious fl ame loss due to poor combustion.
8. BURNER MOTOR-OFF DELAY. The fuel valve
is closed and the burner motor is kept on for the
selected motor-off delay time before the control re-
turns the burner to standby.
SK9805
Burner Preparation
61351