Manual
14
NX Burner With Blocked Vent Safety (BVS) Operation
External Action Appliance Response
Power applied to burner control
Internal safety check conducted. If no light or fl ame is detected and all internal conditions are correct,
control enters idle mode.
Thermostat Calls For Heat
1. Contacts between T and T on Aquastat L7248A are closed.
2. Burner Control period (4 seconds) internal and external check for fl ame or light. If fl ame is detected, control remains in
idle mode.
3. When fl ame is not present, Burner Control will apply power to the burner motor and igniter, complete a 15 second
valve on delay period and then apply power to the oil valve circuit.
4. Burner Control enters the trial for ignition period.
A. Monitors burner for fl ame.
B. When fl ame is not detected:
I. Enters lockout mode after 15 seconds.
II. Shuts off valve, igniter and burner motor.
III. Flashes indicator light at 1 Hz (½ second on, ½ second off ).
IV. Depress reset button to return to power up sequence.
C. When fl ame is detected, Carry-Over period begins:
5. Burner Control enters 10-second Ignition Carry-Over period.
A. Turns on indicator light
B. If fl ame is lost and lockout time has not expired, Burner Control returns to trial for Ignition period.
C. If fl ame is lost and lockout time has expired, Burner Control enters Recycle Mode.
6. Carry-over time expires and igniter turns off .
7. Enters a run mode:
A. Flame is monitored until call for heat ends or fl ame is lost. If fl ame is lost:
B. Control enters Recycle Mode.
I. Recycle time starts (60 seconds).
II. Burner and valve are turned off .
III. Indicator light fl ashes at ¼ Hz (2 seconds on, 2 seconds off ).
IV. Returns to Idle mode at end of Recycle mode.
Call for heat is satisfi ed.
1. Oil valve circuit is de-energized and valve shuts off .
2. Burner motor runs for selected post purge time.
3. Burner motor turns off .
4. Burner Control returns to Idle mode
Reset button pushed two times
without device completing a call for
heat.
1. Burner Control enters restricted mode.
2. Indicator light fl ashes 1 Hz (½ second on, ½ second off ).
3. Reset device by pressing and holding reset button for a minimum of 45 seconds.
GeniSys 7505 Reset Button Operations
Pushing the reset button in the current state will cause the following conditions:
If the burner state is: Pushing the reset button < 1 second Pushing the reset button > 1 second
Push, hold reset button >15
seconds
Lockout Reset from Soft Lockout
Reset from Restricted (Hard)
Lockout
Valve On Delay, Trial For
Ignition, Ignition Carryover
Pump Prime Disable the Burner. Any time the
burner is running, press and hold the
reset button to disable the burner. The
burner will remain off as long as the
button is held.
Enables pump priming: After the
reset button has been held for 15
seconds the button can then be
clicked during the next ignition
sequence to enter pump prime
mode.
Run (igniter is shut off)
Yellow light fl ashes to indicate cad cell
resistance.
Motor-Off Delay, Standby No action
Pump Prime No action Exit pump prime mode and return to standby.
Status Lights
Light Color On Continuously Flashing
Red Restricted (Hard) Lockout Soft Lockout
Green
Flame Sense during normal operation.
May be stray light during standby.
Recycle
Yellow
Control is in Pump Prime mode OR
reset button is currently held for >15
seconds.
Cad cell resistance.
OPERATION AND TROUBLESHOOTING