750-392
CBEX-DE
5-5
Electrical Controls
5.5 — Electrical Controls
The operating controls should be inspected monthly. Examine tightness of electrical connections and keep the
controls clean. Remove any dust that accumulates in the interior of the control using low pressure air. Take care
not to damage the mechanism.
Be certain that controls are correctly leveled. The internal piping leading to the pressure control actuators
should be cleaned, if necessary. Covers should be left on controls at all times.
Dust and dirt can cause excessive wear and overheating of motor starter and relay contacts. Use a burnishing
tool or a hard surface paper to clean and polish contacts. Starter contacts are plated with silver and are not
harmed by discoloration and slight pitting. Replacement of the contacts is necessary only if the silver has worn
thin.
Thermal relay units (overloads) are of the melting-alloy type and, when tripped, the alloy must be given time to
re-solidify before relay can be reset. If the overloads trip out repeatedly when the motor current is normal, replace
them with new overloads. If the condition continues after replacement, it will be necessary to determine the
cause of excessive current draw at the overloads.
Power supply to the boiler must be protected with dual element fuses (Fusetrons®) or circuit breakers. Similar
fuses should be used in branch circuits. Standard one-shot fuses are not recommended.
5.6 — Flame Safety Control
The flame safeguard itself requires little maintenance. Check to see that the retaining screw is securely holding
the chassis to the mounting base. Also check to see that the flame amplifier is tightly inserted.
The relay's self-diagnostic ability includes advising when it is at fault and requires replacement.
A spare unit should be on hand, 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 operation.
It is recommended that service be rotated between the active and a spare control to assure a working replace-
ment 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.
Do not use files or abrasive materials such as sandpaper on the contact points. Failure to follow these instructions
could result in equipment damage.
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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: ......