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 | |
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
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
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
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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