Bosch 125FX LP Installation And Operating Instructions Manual page 15

Mineral deposits can eventually (3-5 years in hard water
areas) corrode the water valve parts to a point where they
will need replacing. Any sign of moisture at the bleed
hole is a sign that the water valve needs to be
replaced immediately.
10. Loose connection at the ECO
Ignition sparker will not operate if the electrical circuit is
interrupted. Check that the connections to the ECO are
secure and tighten if necessary.
11. Reset electrical power to heater
If resetting the electrical power corrected the symptom then
likely the unit's Safety Spill switch (Flue gas safety device
- #9 on page 19) had tripped from a flue blockage during
the previous usage. Inadequate combustion air to the room
area can also cause the unit to improperly vent. Improper
venting or insufficient combustion air must be corrected.
Consult a licensed professional to inspect the installation.
SPARKS APPEAR AT PILOT WHEN HOT WATER TAP
IS TURNED ON, BUT PILOT AND BURNERS WILL NOT
IGNITE
1. Air in the Gas Line
Note: Normally this is a problem only at the time of initial
installation, after the pipes have been worked on, or after a
propane tank has been allowed to empty, or after the heater
has been shut down for a long time.
Bleed all the air trapped in the gas line by turning the hot
water faucet on and off until the air has been cleared from
the line.
2. No gas to the AquaStar
A. Gas cock on gas line may not be open
B. Gas regulator may be shut or damaged. Replace or
unlock the regulator. Note: The regulator furnished with the
heater is exclusively designed for low gas pressure (less
than ½ psig). Excessive pressure will lock it up. Locking
usually happens when the gas pressure between the gas
tank and the water heater's gas regulator has not been
properly regulated. See Page 2 for recommended correct
gas pressure. To unlock a regulator, consult your gas supplier
or call CEC.
3. Pilot orifice clogged or gas valve is dirty
Clogging of the pilot burner can be caused by dust in the
air or dirt in the gas. The pilot orifice or gas filter may need
to be cleaned or replaced. See Fig. 14.
4. Water valve assembly needs to be checked
If the pilot orifice is clean, the water valve assembly should
be checked. The adjustment screw on the water valve micro-
switch may not be tight enough (fig. 15). Remove central
cap beneath micro-switch assembly, carefully loosen the
adjustment screw until the pilot light ignites. At that point
retighten the screw one and a half turns. See Fig 15.
5. Pilot electrovalve switch may need to be replaced
(See Fig 10).
Call CEC.
6. Electronic Control Box may need to be replaced
(See Fig 10).
Call CEC.
PILOT SPARKS CONTINUOUSLY WITH NO WATER
RUNNING
1. Microswitch needs adjustment
If no water is running, but pilot electrode continuously
sparks, the microswitch screw to the water valve needs
adjustment. See Figure 15.
PILOT LIGHTS BUT BURNERS WILL NOT COME ON
1. Confirm the flame sensor is in its proper position.
(see Fig. 13).
2. Sensors for exhaust gases may be loose.
The burners will not come on if the powered fan exhaust is
not working. Check that the unit is plugged in and that the
sensors for the flue gases are secure.
3. Confirm the ECO connections are secure.
4. The Electronic Control Box (Fig 10) may need to be
replaced.
5. Burner electrovalve switch may need to be replaced
(see Fig. 10).
MAIN BURNERS GO OUT DURING HOT WATER USE
1. Deficient exhaustion of flue gases
Check that vent is correct and clear of any obstructions,
that sensors for flue gases are secure and that electrical
connection has been made. If the heater will not come back
on, it will be necessary to turn the electrical supply to
the heater off and then on again.
2. Flow rate diminished below activation rate
Be certain that water flow is not less than required amount
to activate heater.
3. Unbalanced pressure in waterlines
The added restriction caused by the Aquastar in the hot
water system can result in uneven pressures between the
cold and the hot. In such cases when mixing cold water at
the tap, the lower hot water pressure may be overpowered
by a much higher cold water pressure, which may cause
the Aquastar burners to shut down (deactivate). Make sure
faucet aerators or shower heads are free of minerals.
Do not add any flow restrictor to the shower head.
Typically this deactivation symptom is a result of the
hot water being too hot to use comfortably. Warm inlet
water generally causes this. Lowering the control
knob setting and/or reducing the inlet gas supply to
the heater should correct this deactivation symptom.
4. ECO (overheat sensor) tripped due to overheating
Do not feed preheated water to this water heater.
5. Minimum inlet pressure on well pressure tank is
inadequate
Check the inlet water pressure. On a private well, raise the
minimum pressure setting to 30 psi. Confirm that the
pressure tank is not water logged.
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