C. Gas regulator may be shut or damaged.
2.In-line AquaStar gas regulator jammed (usually on LP gas)
Replace or unlock the regulator. Note: The regulator furnished with the heater is designed for low gas pressure. Excessive pressure will lock it up (propane only).
Locking usually happens if the gas pressure between the gas tank (propane) and the water heater’s gas regulator has not been reduced. See page 2 for recommended correct gas pressure. To unlock a regulator, consult your gas supplier.
3.Pilot orifice clogged and/or air screen dirty, or pilot gas filter is dirty.
Clogging of the pilot burner can be caused by dust and any suspended matter contained in the ambient air. Although the filters can lengthen the cleaning intervals, they can never completely prevent such clogging. In consequence the gas jet issuing from the pilot orifice is reduced and or the air mixture is reduced. The pilot flame is weak and thus can no longer heat the thermocouple sufficiently. For cleaning purposes, the air filter screen is pulled off, washed and blown out. The pilot orifice has likewise to be cleaned or exchanged. To clean the pilot consult a gas service person.
4. 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. Because of the very small pilot orifice (especially on LP gas models), bleeding out all the air could take several minutes. Depress the pilot button ( 
) until all the air has escaped, and the gas has arrived. During this process, press repeatedely on the piezo ignition button until the pilot flame has ignited.
PILOT LIGHTS BUT FLAME GOES OUT WHEN BUTTON IS RELEASED
1.Pilot push button was not pushed in far enough or was not held in long enough
Once pilot flame has been lighted. Hold button pushed in for at least 15 seconds to give time for the pilot flame to properly heat the tip of the thermocouple.
2.Pilot flame improperly aimed or is too weak so it is not properly heating the tip of the thermocouple.
The Pilot flame should be a sharp blue flame and aimed at the tip of the thermocouple so that it envelops 10 mm (3/8 “) of the thermocouple tip. Pilot flame has to be properly aimed at the thermocouple. See Fig 8.
3.Poor thermocouple connection at the electromagnet
Note: Electromagnet is part #8707201094 located on the right side of the gas valve behind the piezo pushbutton assembly. Check the tightness of the thermocouple connection nut at the electromagnet: The
Tighten the thermocouple nut snugly but not too tight.
4.Poor circuit connections at the ECO. (Energy Cut- Off overheat protection)
Oxidation or looseness of the ECO terminal connections can result in millivolt current loss through the thermocouple safety circuit. Clean terminals with very fine sand paper or an eraser and reconnect ECO leads.
5. Faulty ECO (part #8707206017)
If cleaning the terminals attached to the ECO did not fix the problem, connect a jumper wire between the two wires and try to relight the pilot. If the pilot flame now remains on, replace the ECO. If the flame still goes out when the button is released, the ECO is not defective. Go to next step.
6.Faulty thermocouple (part #8747202083) or electromagnet) Unless these 2 parts are at least 8 to 10 years old, it is very unlikely that they are faulty. Before testing, reconfirm that #2 is absolutely correct, and that all connections are clean and tight.
To test the thermocouple, disconnect the thermocouple lead to the ECO. Insert a
Consult a gas service person to test and change the thermocouple.
BURNERS DO NOT IGNITE WHEN HOT WATER IS TURNED ON OR WHEN A CIRCULATOR PUMP IS OPERATING
1. Pilot is not on.
Light the pilot. See lighting instructions.
2.Gas valve button not positioned on Burner Position Be sure once the pilot flame is on, that after a 15 to 20
second wait, the main burner button ( 
) is pushed all the way in.
3.Water flow rate at hot water tap is too low. Note: The AquaStar models 125BL require 1.8 gallon per minute flow to activate the burners. This is a flow which would fill a quart jar in 8 seconds.
4 . Cold water inlet filter on heater is dirty.
Remove filter and clean. This screen filter is located at the inlet side of the brass water valve (fig 11, #32). Check and clean faucet aerators too.
5. Inadequate pump used on a recirculating loop
If unit is plumbed in a recirculating loop system verify that the primary circulator pump is sized properly. GF
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