Cleaver-Brooks CBH 40 - Motorized Gas Valve; Solenoid Valve; Refractory

the valve and the escape pipe is recommended. See
Figure 1-7. The discharge piping must be properly
arranged and supported so that its weight does not
bear upon the valve.
Do not paint, oil, or otherwise cover any interior or
working parts of the safety valve. A valve does not
require any lubrication or protective coating to
work properly.
Follow the recommendations of your boiler in-
spector regarding valve inspection and testing. The
frequency of testing, either by the use of the lifting
lever or by raising the steam pressure, should be
based on the recommendation of your boiler in-
spector, and/or the valve manufacturer, and in ac-
cordance with sections VI and VII of the ASME
Boiler and Pressure Vessel Code.
Avoid excessive operation of the safety valve as
even one opening can provide a means of leakage.
Safety valves should be operated only often enough
to assure that they are in good working order.
When a pop test is required, raise the operating
pressure to the set pressure of the safety valve,
allowing it to open and reseat as it would in nor-
mal service.
Do
not hand operate the valve with less than 75%
of the stamped set pressure exerted on the under-
side of the disc. When hand operating, be sure and
hold the valve in an open position long enough to
purge accumulated foreign material from the seat
area and then allow the valve to snap shut.
Frequent usage of the safety valve will cause the
seat and disc to become wire drawn or steam cut.
This will cause the valve to leak and necessitate
down time of the boiler for valve repair or replace-
ment. Repair of a valve must be done only by the
manufacturer or his authorized representative.
Avoid having the operating pressure too near the
safety valve set pressure. A 10% differential is
recommended. An even greater differential is
desirable and will assure better seat tightness and
valve longevity.
Steam is expensive to generate and, for the sake of
economy, wastage should be avoided whenever
possible.
K. MOTORIZED GAS VALVE
Should the valve fail to operate, check its opera-
tion by applying test leads of the proper voltage to
terminals 1 and 2 of the actuator. Make certain
that the main shut off cock is closed prior to test-
ing. If the actuator fails to operate, it must be
replaced. The actuator is not field repairable nor
should it be disassembled.
To remove the actuator, loosen the two 5/32" allen
setscrews that hold the actuator collar to the valve
bonnet.
Chapter 5--Ad.iustment and Maintenance
After replacement, cycle the valve with the fuel
shut off to determine that it opens and closes. If
the valve has a visual indicator, observe the
colored indicator; yellow - shut; red - open.
The auxiliary switch normally used as a valve
closed indication switch is replaceable as a com-
ponent.
L. SOLENOID VALVES:
GAS PILOT~FUEL OIL-VENT VALVES
Foreign matter between the valve seat and seat
disc can cause leakage. Valves are readily dis-
assembled, however, care must be used during dis-
assembly to be sure that internal parts are not
damaged during the removal and that re-assembly
is in proper order.
A low hum or buzzing will normally be audible
when coil is energized. If valve develops loud buz-
zing or a chattering noise check for proper voltage
and clean plunger assembly and interior plunger
tube thoroughly. Do not use any oil. Make sure
that plunger tube and solenoid are tight when re-
assembled. Take care not to nick, dent or damage
the plunger tube.
Coils may be replaced without removing the valve
from the line. Be sure to turn off power to the
valve. Check coil position and make sure that any
insulating washers or retaining springs are rein-
stalled in proper order.
M. REFRACTORY
The Cleaver-Brooks boiler is shipped with com-
pletely installed refractory. This consists of the
rear head, the inner door and the furnace liner.
Normal maintenance requires little time and ex-
pense and prolongs the operating life of the refrac-
tory. Preventive maintenance through periodic in-
spection will keep the operator informed of the
condition of the refractory and will guard against
unexpected and unwanted down time and major
repairs.
Frequent wash-coating of refractory surfaces is
recommended. High temperature bonding air-dry
type mortar, diluted with water to the consistency
of light cream, is used for this purpose. Re-coating
intervals will vary with operating loads and are
best determined by the operator when the heads
are opened for inspection.
Rear Door
The rear door is a steel shell containing horizontal
baffle tiles and lined with insulation material and
castable refractory (See Figure 5-8).
Burned or discolored paint on the outer surface of
the door does not necessarily indicate refractory
trouble, but may be an indication of other con-
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