750-392
CBEX-DE
4-5
Flame Loss Sequence
The lockout switch must be manually reset following a safety shutdown. The cause for loss of flame or any
unusual condition should be investigated and corrected before attempting to restart. Failure to follow these
instructions could cause damage to the equipment.
No pilot flame:
The pilot flame must be ignited and proven within a 10-second period after the ignition cycle
begins. If not proven within this period, the main fuel valve circuit will not be powered and the fuel valve(s) will
not be energized. The ignition circuit is immediately de-energized and the pilot valve closes, the reset switch
lights and lockout occurs immediately. The blower motor will continue to operate.
The flame failure light and the alarm bell (optional) are energized 10 seconds later.
The blower motor will be de-energized. The lockout switch must be manually reset before operation can be
resumed.
Pilot but no main flame:
When the pilot flame is proven, the main fuel valve circuit is energized. Depending
upon the length of the trial-for-ignition period, the pilot flame will be extinguished 10 or 15 seconds later. The
flame detecting circuit will respond to de-energize the main fuel valve circuit within 2 to 4 seconds to stop the
flow of fuel. The reset switch lights and lockout occurs immediately. The blower motor will continue to operate.
The flame failure light and alarm bell (optional) are energized 10 seconds later.
The blower motor will be de-energized. The lockout switch must be manually reset before operation can be
resumed.
Loss of flame:
If a flame outage occurs during normal operation and/or the flame is no longer sensed by the
detector, the flame relay will trip within 2 to 4 seconds to de-energize the fuel valve circuit and shut off the fuel
flow. The reset switch lights and lockout occurs immediately. The blower motor continues operation. The flame
failure light and alarm bell (optional) are energized 10 seconds later.
The blower motor will be de-energized. The lockout switch must be manually reset before operation can be
resumed.
The program relay has the capability to self-diagnose and to display a code or message that indicates the failure
condition. Refer to the control manual for specifics and suggested remedies. Familiarity with the program relay
and other controls in the system can be obtained by studying the contents of the appropriate manuals.
Knowledge of the system and its controls will make troubleshooting much easier. Costly downtime or delays can
be prevented by systematic checks of the actual operation against the normal sequence to determine the stage at
which performance deviates from normal. Following a routine may possibly eliminate overlooking an obvious
condition, often one that is relatively simple to correct.
Preventive maintenance and scheduled inspection of all components should be followed. Periodic checking of the
relay is recommended to see that a safety lockout will occur under conditions of failure to ignite either pilot or
main flame, or from loss of flame.
Do not attempt to circumvent any of the boiler safety features.
Doing so could result in unsafe operating conditions
or damage to the equipment.
!
Caution
Summary of Contents for CBEX-DE
Page 1: ...CBEX DE Dryback Elite Boiler 250 800 HP Operation and Maintenance 750 392 10 2019 ...
Page 54: ...Preparations for Startup 3 22 750 392 CBEX DE ...
Page 74: ...Startup and Operation 4 20 750 392 CBEX DE ...
Page 104: ...Inspection and Maintenance 5 30 750 392 CBEX DE ...
Page 122: ...Parts 6 18 750 392 CBEX DE 6 11 Temperature Controls Hot Water ...
Page 124: ......
