Pilot Lights but Burners will not Come on

PILOT LIGHTS BUT BURNERS WILL NOT COME ON

1.Confirm water valve assembly is working properly. See Water Valve under MAINTENANCE AND SERVICE.

2.Confirm the flame sensor is in its proper position and clean, lightly wipe clean if dirty. See Fig. 10

3.Confirm the burner electrovalve switch is functioning properly.

Measure milivoltage at burner electrovalve (see Fig. 13).

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

Check wire connections and test operation of electronic control box (see Fig. 13).

Fig. 13 - Electrical wiring diagram

1	burner electrovalve	8	electronic control box
2	gas control valve	9	LED failure indicator
3	pilot electrovalve	10	LED indicator main
4	flame sensor		burner operation
5	pilot electrode	11	on/off switch
6	overheat sensor	12	hydro-generator
7	temperature limiter	13	flue gas safety device

MAIN BURNERS GO OUT DURING HOT WATER USE

1.Flow rate diminished below activation rate Increase hot water flow rate.

2.Unbalanced pressure in the water lines

The added restriction caused by the 125 HX 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 125 HX burners to shut down. Make sure faucet aerators and showerheads are free of minerals and dirt. Do not add any flow restrictor to the shower head.

3.Minimum inlet pressure on well 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.

4.ECO (overheat sensor) tripped due to overheating re-ignite the appliance 10 minutes later. If it happens again, contact your service person.

5. Flue gas safety device tripped

Ventilate the room and operate the appliance 10 minutes later. Provide more combustion air to the room and/or inspect and correct venting system. Afterwards, if it happens again, contact your service person.

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 too hot (as with solar preheated water or high ground water temperatures)

Decrease gas pressure. Note: Only the model 125B LPS or 125B NGS should be used if the inlet water is preheated.

3. Ground water temperature is very warm

Reduce inlet gas supply to heater when inlet water temperature is very warm (60-70 F). See also HOT WATER TEMPERATURE FLUCTUATES / UNIT DEACTIVATED.

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.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

thecorrectgaspressure

See specifications on page 3. 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 3 for correct gas pressure settings and fig. 5 for locations where gas pressures are taken.

3.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.

4.Cold water is mixing with the hot water between the

125HX and the outlet

Compare water temperature at outlet of the 125 HX (hold the 125 HX 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 #2).

5.Parts in water valve are dirty or damaged, which will prevent the gas valve from being fully opened.

Water valve maintenance needs to be performed, see #6 under NO SPARK AT THE PILOT

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125HX LP, 125HX NG specifications

The AquaStar 125HX NG and 125HX LP are highly efficient gas tankless water heaters designed to meet the demands of modern households. With their compact size and advanced technology, these units provide an endless supply of hot water while maintaining energy efficiency. Both models cater to natural gas and propane applications, making them versatile options for various installations.

One of the standout features of the AquaStar 125HX series is its ability to deliver a powerful output of up to 199,000 BTUs, ensuring that multiple hot water outlets can operate simultaneously without a drop in temperature. Users can enjoy the convenience of hot showers, laundry, and dishwashing all at once, making it an ideal choice for busy families or households with high hot water needs.

These models incorporate a sophisticated modulating gas valve that adjusts the gas flow based on the demand for hot water. This technology not only optimizes energy consumption but also contributes to extended unit life by minimizing wear and tear on the components. The AquaStar 125HX units also come equipped with a patented electronic ignition system, which eliminates the need for a standing pilot light and reduces gas consumption.

Furthermore, the AquaStar 125HX NG and 125HX LP feature a durable heat exchanger constructed from high-grade copper, which enhances thermal efficiency and prevents corrosion. This ensures a longer lifespan and increased reliability for homeowners. Additionally, the units are compact and wall-mounted, allowing for flexible installation in various spaces, including tight utility closets or outside walls.

Safety is also a top priority, with built-in overheat protection and a freeze protection feature that ensures the unit remains operational even in colder climates. The AquaStar 125HX series operates quietly, allowing users to enjoy the benefits of hot water without the disruptive noise commonly associated with traditional water heaters.

In summary, the AquaStar 125HX NG and 125HX LP are leading choices in the tankless water heater market, combining efficiency, reliability, and innovation. Their impressive output, advanced technologies, and compact design make them suitable for modern living, ensuring homeowners have access to hot water whenever they need it. With these features, AquaStar continues to set a high standard in water heating solutions.