38
Blow pilot flame out. The reading when the protection
valve closes (drop-out point) should be at least 5 MV
below first reading. If first reading is correct, but drop-
out point is not, problem is in the combination control
valve. An open circuit check of the thermocouple
should give a meter reading of 30 to 40 MV.
Gas Combination Control Valve Replacement
Disassembling this control is not recommended. If
the control is not working, replace the entire control.
To remove the control, remove the two screws on the
control box cover on which the generator push button
switches are mounted. Disconnect wires and conduit
running to the combination control valve. Disconnect
thermocouple lead and pilot gas supply tube from
control and uncouple pipe unions on each side of the
control.
ELECTRIC GENERATORS
Magnetic Contactor
The contactor can be serviced by removing the cover
of the contactor box.
A noisy contactor (hum or chatter) is generally due to
enough dust or dirt on the armature pole faces or
around the armature core that the magnet coil cannot
pull the armature into a completely sealed position.
This can usually be corrected by blowing or wiping the
pole faces clean. To inspect contactor contact points,
remove cover at top of contactor by removing two
screws which hold it in place. Replace contactors if
points are pitted or burned.
Electric Element
To determine whether all elements are heating
properly, use an ampmeter with power ON to the
elements. See wiring diagram for amperage ratings.
Always check that the supply voltage and the voltage
rating of the element agree.
To replace an element, drain water from generator
shell. Remove cover of contactor box, remove electric
wires to that element’s terminals, remove bolts through
flange of element and pull element forward. When
replacing an element, always use a new gasket. The
flange and tube surfaces which contact the gasket
must be clean.
If removed element shows a pronounced scale build-
up on its heating tubes, the other elements should be
removed and mechanically cleaned to remove the
scale. This will prolong their life. DO NOT immerse
elements in a chemical solution to descale.
Inoperative Control Circuit (Generator Control and
Compartment Controls)
If the steamer is equipped with a step down
transformer, check transformer for proper operation.
If there is a separate 120 volt line for control circuit,
check this line for power.
REGENERATING (STEAM COIL) GENERATORS
The steam coils are intended for use at a steam supply
pressure of 15 psi maximum. A pressure regulating
valve is available as optional equipment for steamers
where the steam supply pressure exceeds 15 psi.
Regulators of a different make and type may be
supplied at different times and to meet special
conditions; therefore, no specific service information for
the regulator is included here. The regulator used will
be of the adjustable type and should be set for a
discharge pressure of 15 psi. A pressure gauge is
provided to indicate the regulator discharge pressure.
The regulator should be set when steam is flowing
(steam solenoid valve is open). If steam is heavy with
condensate, install a ball float trap in the steam line
before the pressure regulating valve.
To remove a steam coil, disconnect union in steam
supply line to the coils and in the condensate discharge
line from the coils. Remove header that supplies
steam to coils by disconnecting union at each coil. In
same way, remove coil condensate collection header.
Remove four bolts clamping each coil flange in place
and pull coil forward. Use a new flange gasket when
replacing coil. The faces that mate with gasket must
be clean.
Turn steamer power switch ON, allowing steam
generation and, consequently, pressure to rise to
normal operating level and then turn power switch
OFF for a final purging of boiler and steam supply
lines.
Steamer is now ready for use.
