Repair manual

PROBE SYSTEM: ELECTRIC WATER FILL AND
ELECTRIC LOW WATER FUEL CUT OFF FOR STEAM
GENERATOR — 3 PROBE TYPE
WARNING: Service of the steam generator must be performed only
by trained and experienced service technicians.
During operation of the steam generator, the water level is maintained automatically by unequal length probe
extensions inside The probes and extensions must be Kept clean ana free of scale deposits in order to function
properly
The probe extensions are sensors in a control system
which monitors and maintains the water level between
the end of the short probe extension and the end of the
intermediate extension.
The long probe, called "Low Water." is a safety sensor which shuts off the fuel supply if there is insufficient water in the steam
generator.
Since the control system is all electric and these parts don't move or wear. they can be expected to have a long life. If they do
malfunction, it is generally because untreated hard feedwater is being used in the steam generator. This forms scale on the
submerged ends of the probe extensions and on the top horizontal surfaces of the probes. After this scale is removed, the parts
will function properly.
To eliminate the cause of scaling, refer to separate data sheets for feedwater treatment information and corrosion protector
servicing instructions. Probes and probe extensions should be wiped clean each time the corrosion protector is replaced.
Erratic operation may result from loose connections on either end of the probe. The external end of the probe has a nut to hold
the wiring terminal snugly to the probe. This nut, if loose, may be tightened, firmly but gently. Too much torque will turn the
center piece of the probe and misalign the attached probe extension inside, causing the probe to become inoperative.
Inside the steam generator, the screw which holds the probe extension to the probe may be loose, allowing the probe extension
to swing or rest against some part of the steam generator. This can be corrected by removing the hand hole plate and reaching
inside to align and hold the probe extensions vertically while tightening the screws.
To Service the Probes or the Probe Extensions
1) Turn off all utilities and fuel to steam generator. Drain Steam generator.
CAUTION: Never work on the steam generator when it is hot or pressurized.
2) Remove probe cover on outside of steam generator to expose probe terminals. Examine for loose wiring terminals.
3) Remove hand hole cover plate from steam generator. See separate data sheet for instructions.
4) Remove probe extensions from probes on inside of steam generator, clean off scale, and re-install. Or, install new probe
extensions if preferred.
5) Remove scale from the probe (see sketch above). Do not use an abrasive on the teflon insulator. If the old probe needs
replacement, install a new one.
(CONTINUED ON THE REVERSE SIDE)
SERVICING
INSTRUCTIONS