Maintenance & Service - Bosch 125FX LP Installation And Operating Instructions Manual

between will give various temperatures between 140° and
95°F at various flow rates between 2.0 and 4.0 gallons per
minute. The position you select on the temperature selector
dial will depend on the temperature of the incoming water
(50°F is average in the U.S.). In warm weather regions where
the incoming cold water is generally warmer, or during the
hot weather months in some other areas a midway setting
on the temperature selector knob will produce a
temperature rise of about 70°F, giving an output of
approximately 120°F. At this setting, if it is still necessary,
one could mix a small amount of cold water in a shower
and have a comfortable shower at about 3 gallons/minute.
During the colder months, or in cold climate areas, it might
be necessary to set the control all the way clockwise to
the right for maximum temperature rise.
Do not supply the AquaStar 125FX with preheated water.
For this type of application, purchase a solar model 125 B
LPS or 125 B NGS.
Fig. 12 - Temperature Adjustment Knob
MAINTENANCE AND SERVICE
REVIEW MAINTENANCE TABLE ON
THE BACK OF THIS MANUAL
Approximately once a year, the AquaStar should be checked
and cleaned. To remove the front cover, first remove the
incandescent particle tray, then pull off the temperature
adjustment knob and unscrew and remove the plastic collar.
Unscrew the central screw located at the bottom of the
front cover. Pull main cover out toward you and lift up and
out. THE FOLLOWING OPERATIONS SHOULD BE
PERFORMED BY A QUALIFIED SERVICE PERSON:
Vent System: Should be checked annually. Clean and repair
as needed.
Water Valve (Part # 87070024534): The water valve on
this heater should be serviced periodically. Lubricate
component #33 on page 19 with a small amount of silicon,
faucet or lithium grease every two years to keep its o rings
fresh and pushrod sliding smoothly. Every 3-5 years replace
components #33 and #34 on page 19. The frequency will
depend on the mineral content of the water and conditions
of use or whenever signs of corrosion appear at the gas
and water valve joint. Periodically check that the water inlet
filter (#36 on page 19) is clean as well.
Pilot Flame: The pilot flame should burn with a clean,
sharp, blue flame and should resemble the diagram in Fig.
13. If the flame is soft and yellow, the pilot burner orifice
may need to be cleaned or replaced. The pilot flame should
be approximately 2 inches long, extending past the flame
sensor. If the flame is too small, it will not reach the flame
sensor and the burners will not come on.
TEMPERATURE
ADJUSTMENT KNOB
Fig. 13 - Characteristic Pilot Flame
To clean the pilot burner and/or the pilot orifice: Turn
off the gas at the unit (Position 'O'). Remove the cover of
the heater. To do so, pull off the temperature knob and
unscrew and remove the temperature knob collar. Pull main
cover out toward you and lift up and out. The pilot orifices
should also be cleaned or replaced. Do not enlarge the
orifice (see fig. 14). Do not use any wire or sharp object
to clean orifices. Natural gas orifices are large enough that
you can usually clean them by blowing through them. LP
orifices, on the other hand, are too small to clean and should
be replaced. See #3 in Trouble Shooting Section. To access
the pilot orifice, remove 2 screws holding pilot assembly in
place. Then loosen the compression fitting and lift up pilot
burner to expose pilot orifice.
3mm
Correct gap between pilot
burner tip and electrode tip
Piezo Electrode
Flame sensor
Piezo
Electrode
13