Inspection and Maintenance
8-6
750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
8.6 — Flame Safety Control
The microprocessor based control requires minimal maintenance because the safety and logic timings are inaccessi-
ble. There also are not any accessible contacts. Check to see that the retaining screw is securely holding the chassis
to the mounting base. Also check to see that the amplifier and the program module are tightly inserted.
The relay’s self-diagnostic ability includes advising when it or its plug-in modules are at fault and require replace-
ment.
Your spare control should be stored in a dry atmosphere and wrapped in plastic. During an extended shutdown
(e.g., seasonal) the active control should be removed and stored. Moisture can cause problems with control opera-
tion.
It is recommended that service be rotated between the active and a spare control to assure a working replacement
is available.
Be sure the connecting contacts on the control and its base are not bent out of position.
The flame detector lens should be cleaned as often as operating conditions demand. Use a soft cloth moistened
with detergent to clean the lens.
A safety check procedure should be established to test the complete safeguard system at least once a month, or
more often. Tests should verify safety shutdown and a safety lockout upon failure to ignite the pilot, upon failure to
ignite the main flame, and upon loss of flame. Each of the conditions should be checked on a scheduled basis.
The following tests should be used to test the complete safeguard system. If the sequence of events is not as
described, then a problem may exist. Contact your local Cleaver-Brooks authorized representative for assistance.
8.6.1 — Checking Pilot Flame Failure
1. Close the gas pilot shutoff cock and shut off the main fuel supply.
2. Turn the burner switch “on.”
The pilot ignition circuit will be energized at the end of the pre-purge period. There should be an ignition spark,
but no flame. Since there is no flame to be detected, the program relay will signal the condition. The ignition cir-
cuit will de-energize and the control will lock out on a safety shutdown. The flame failure light (and optional
alarm) will be activated. The blower motor will run through the post-purge and stop.
3. Turn the burner switch “off.”
4. Reset the safety switch.
5. Re-open the gas pilot shutoff cock and re-establish main fuel supply.
When replacing a control, be sure to lock out the main power supply switch since the control is “hot” even though the
burner switch is off. Failure to follow these instructions could result in serious injury or death.
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