Sequence Of Operation - Beckett CG10 Manual

Figure 9. Typical wiring using Model RM7897A (for reference only)
L1
AIR
PROVING
SWITCH
FLAME ROD
SEE NOTE 1

Sequence of Operation -

(typical for RM7895A fl ame safeguard primary control)
1. Initiate – The primary control enters the INITI-
ATE sequence when the control is fi rst powered
on or power returns after an interruption. The
initiate sequence is a ten second delay during
which the control verifi es line voltage stability.
2. Standby – The control enters STANDBY until
the limits, operating limit control, burner switch,
and all microcomputer-monitored circuits are in
the correct state.
3. Load demand – Operating limit control contacts
close on drop in temperature (or pressure) and
initiates the start sequence.
4. Prepurge – The control will signal the PRE-
PURGE sequence when the airfl ow interlock
and all switches are in the correct state. The Pre-
purge sequence is the amount of time the blower
motor runs prior to the ignition start sequence.
Timing for the Prepurge sequence is determined
by a card mounted inside the control module
(typically 30 seconds).
12
LINE VOLTAGE SERVICE 120V 60Hz
L1
FROM FUSED DISCONNECT
SUPPLIED BY INSTALLER
HIGH GAS
LOW GAS
**
PRESSURE L.W.C.O.
PRESSURE
L
C
TRANS
GV1
BK
K
BK
GV2
D
BL
E
MOTOR
L2
**
**
OPERATING
HIGH
CONTROL
LIMIT
A
OR
A
OR
A
A
5. Trial for ignition (TFI) – After the Prepurge se-
quence has timed out, the ignition and main gas
valves will be energized. Because the burner
has direct spark ignition for the main fl ame, the
fl ame must be established and detected by the
control within 4 seconds or lockout will occur.
6. Run – With a fl ame established and the control
continuing to detect a fl ame, the burner will op-
erate in the RUN mode until the load demand is
satisfi ed or a limit opens.
7. Load Satisfi ed – The burner switches to idle un-
til the next call for operation.
This operation sequence is typical and for reference
only. The primary control could vary, depending on the
customer specifi cation and code requirements. For the
specifi c operating sequence that applies to your instal-
lation, consult the appliance manufacturer's directions,
wiring instructions, and control manufacturer's literature
supplied with your burner.
NOTICE
6104 BCG10 R0
8