Bosch Appliances 125X NG Pilot Sparks Continuously with no Water Running, Water is TOO HOT

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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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Contents For Your Safety Table of ContentsWhat to do if YOU Smell GAS Features AquaStar 125X LP and 125X NG SpecificationsUnpacking the Aquastar Heater Principle of OperationAquastar Model Proper Location for Installing Your Heater Where IT could FreezeGeneral Rules to Follow For Safe Operation Mounting Installation Combustion AIR RequirementsClearances Venting To check the draftMaximum Inlet GAS Flow Pressure Setting GAS Line SizingAltitude Natural Gas Liquid Propane For Your Safety Read Before Operating Your HOT Water Heater Water ConnectionsOperating Instructions Setting the Water Temperature Lighting and Operating InstructionsTo Turn OFF GAS to Appliance Maintenance and Service Review Maintenance Table on the Back of this ManualDo not enlarge the orifice IntroductionNo Spark AT the Pilot HOT Water Temperature Fluctuates / Unit Deactivated Pilot Sparks Continuously with no Water RunningPilot Lights but Burners will not Come on Water is TOO HOTSee page 2 and 7 for correct specifications Gas pressure is too lowInterior Components Diagram and Parts List Interior Components Diagram Parts List Installation Checklist Model GAS Line Size Controlled Energy Corp