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Chapter 7
servicing the strainer, fuel supply and return line valves
should be shut off. The strainer should be drained of oil and
any sediment collected at the bottom of the canister. Remove
the cover and withdraw the strainer element. Replaceable
elements should be disposed of properly. Reusable elements
may be cleaned by immersing them in solvent until attached
deposits have been loosened, and then shaking them dry.
WARNING
! DANGER
Use only safety type solvents for cleaning
strainers or other components. Work only in
a well ventilated area. Do not use gasoline
or other flammable liquids as a solvent. Do
n o t d r y t h e s t r a i n e r e l e m e n ts w i t h
compre sse d air. Failure to heed this
warning could result in serious personal
Injury or death.
Reassemble the strainer, taking care to seal the canister
properly to avoid air infiltration and resulting loss of suction.
Open the fuel supply and the return line valves.
G. GAS BURNER MAINTENANCE
Refer to the burner sections for specific information
regarding operation and maintenance of the burner. The
motorized gas valve requires little maintenance, as the
operating mechanism is immersed in oil and completely
sealed. However, proper operation should be checked on a
routine basis.
Keep the outer parts of the valve(s) clean, especially the stem
between the operator and the valve. A nicked, scored, or
otherwise damaged valve stem can cause leakage. Do not
remove dust covers if installed.
The stem packing gland is the O-ring type. If oil is noticed
around the operator base, or if leakage occurs, the valve must
be repaired. If the actuator is sluggish or fails to operate, and
the oil level is known to be correct, the operator portion
should be replaced.
Solenoid Valves
Foreign matter between the valve seat and the seat disc will
cause leakage. Valves are readily disassembled; however,
care must be taken to see that internal parts are not damaged
during removal and that reassembly is in the proper order.
A low hum or buzzing will normally be audible when the
solenoid coil is energized. If the valve emits a loud buzzing
or a chattering noise, check for proper voltage. If voltage is
correct, clean the plunger assembly and interior plunger tube
thoroughly. Do not use any oil. Make sure that the plunger
tube and solenoid are tight when assembled. Take care not to
nick, dent, or damage the plunger tube.
7-6
Inspection and Maintenance
Solenoid coils can be replaced without removing the valve
from the line.
WARNING
! DANGER
Be sure to disconnect the main power
supply to the boiler in order to prevent the
possibility of electrical shock, which could
result in serious personal injury or death.
Check the coil position and make sure that any insulating
washers or retaining springs are reinstalled in the proper
order.
H. REFRACTORY
The boiler is shipped with completely installed refractory.
High temperature refractory lines the burner door and floor of
the boiler. Front and rear walls, side casing panels, the roof
section, the bottom drum and the drum vent are protected
with high temperature insulation. Preventive maintenance
through periodic inspection will keep the operator aware of
the condition of the refractory and insulation and will guard
against unexpected downtime for repairs.
I. CASING SEALS
The most obvious indication of a problem is the appearance
of discolored paint on the casing or soot and hot gases
escaping at seal joints. It is important that at start-up any
problems are noted and corrected before the boiler is put back
into operation. The following are areas requiring inspection.
Burner Dry Oven
Inspect the area around the dry oven and look for discolored
paint or evidence of combustion gas leakage. If a problem is
noted look for warped sealing surfaces and make sure that the
insulation on the front wall around the dry oven has not
pushed away from the wall. Cracks may appear in the burner
dry oven refractory as a result of expansion and contraction
from operation. If cracks are larger than 1/8" when the
refractory is cooled, the cracks should be filled with a high
temperature bonding air-dry mortar such as Cleaver- Brooks
"Corline."
Access to the boiler furnace area is gained through an access
port at the rear of the boiler
Drum Seals
Inspect the areas around the drum seals and look for soot or
hot gas leaks. If a problem is noted look for the source of the
leak. Remove the old insulation and sealant from around the
drum. Using a pumpable insulation material (p.n. 872-680),
fill the void flush with the outside of the wall. Allow the area
to set up and apply a thick bead of high temperature silicone
around the drum and install the cover plates.
750-364
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