Bosch Appliances 125FX NG, 125FX LP specifications Temperature Adjustment Knob

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.

TEMPERATURE

ADJUSTMENT KNOB

Fig. 12 - Temperature Adjustment Knob

MAINTENANCE AND SERVICE

REVIEW MAINTENANCE TABLE ON THE BACK OF THIS MANUAL

Approximately once a year, theAquaStar 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.

3mm

Correct gap between pilot burner tip and electrode tip

Piezo Electrode

Flame sensor

Piezo

Electrode

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.

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