Bosch Appliances 125X NG, 125X LP specifications Pilot Sparks Continuously With No Water Running

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 12.

PILOT LIGHTS BUT BURNERS WILL NOT COME ON

1.Confirm water valve assembly is working properly.

2.Confirm the flame sensor is in its proper position.

3.Confirm the burner electrovalve switch is functioning properly.

Call CEC

4.The electronic Control Box (Fig. 13) may need to be replaced.

Call CEC.

E661_002

Fig. 13 - Electrical wiring diagram

4	electronic control box	114	gas control valve
43	pilot electrovalve	115	burner electrovalve
51	pilot electrode	116	battery compartment
52	flame sensor		1.5V D batteries (2)
96	microswitch assembly	119	overheat sensor
99	on/off switch

WATER IS TOO HOT

1. Temperature Selection too high

Turn the temperature adjustment knob counter-clockwise (to the left) to lower the maximum water temperature.

Note: This will increase the activation flow rate.

2.Inlet water temperature is very warm (60º-75ºF) Reduce inlet gas supply to lower the heaters degree rise. Note: Only the Model 125BS should be used if the inlet

water is preheated.

WATER IS NOT HOT ENOUGH

1. Temperature selection too low.

Change the setting. Turn the temperature adjustment knob clockwise (to the right).

Note: This will decrease the activation flow rate.

2.Water flow through the heater is higher than the capacity of the AquaStar to heat it

Reduce the flow demand at the faucet. See flow rates at specific temperature rises on page 2.

3.Btu input is too low due to insufficient gas pressure It is extremely important for a tankless instantaneous water heater to have the right size gas line to obtain the correct gas pressure

See specifications on page 2. Unlike storage tank water heaters, the burners of a tankless water heater must be very powerful to heat water instantaneously since they do this only at the time hot water is actually being used. It is therefore imperative that the gas pressure requirement be met exactly. Insufficient gas pressure will directly affect the water temperature at the time of usage. See page 2 for correct gas pressure settings and fig. 14 for locations where gas pressures are taken.

4.Btu input is too low due to insufficient gas supply Make sure your main gas line is fully opened. If using LP gas, be sure that the size of the propane tank is adequate to supply the required gas pressure.

5.Cold water is mixing with the hot water between the AquaStar and the outlet

Compare water temperature at outlet of the AquaStar (hold the AquaStar’s outlet pipe with your hand) and at the tap. If these two are very different, check for mixing valve or plumbing crossover (see “NO SPARK AT THE PILOT” paragraph #4). Where automatic “anti-scald” valves are required by code, lower the temperature setting on the AquaStar as much as possible and balance the pressure between cold and hot water after the AquaStar.

6.Parts in water flow valve are corroded so that the gas passage is not fully opening.

HOT WATER TEMPERATURE FLUCTUATES / UNIT DEACTIVATED

1. 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.

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