I have propane fed tankless water heater with an electrical (battery powered) igniter. It died suddenly - checked batteries, voltage is fine there - and no change when new batteries are installed; gas supply is fine; lines are clean. There is no spark to start the pilot when the hot water line is on; and the red LED indicator light is not lit. (I believe LED is supposed to be lit when the unit is “on” and goes to flashing when the batteries are low. )
My best guess is that the igniter module - that apparently generates a HV AC for the ignition spark - is bad and needs to be replaced? Alternatives diagnoses??? Anything else I can check with a VOM to confirm diagnosis?
Many thanks.
I also have a bosch aquastar tankless heater that uses propane except mine has the pilotless feature where the water moving through the unit generates the spark to light the propane (hydrogenerator…water spins a magnet inside a coil and makes the electricity). I had the same problem and found that the line that goes outside from the powervent module was clogged by some type of insect that made a nest in it. The safety feature shut the unit down…that took me several hours to figure out. If you have the powervent (takes the exhaust gases out of the house) and it has the stainless steel tubing going through the wall to vent outside…check that thin tube outside and see if it is clogged.
Right now mine won’'t make a spark either…I am getting no voltage from the hydrogenerator and a replacement generator is around $125 and is nonreturnable. I wish I could find a place to buy parts for the hydrogenerator…all I need is the flow wheel/magnet…probably a two dollar piece. My magnet has a crack in it and I think it is the problem.
I wonder if it is possible to change the aquastar 125HX over to a battery powered spark or even one that uses 110 volts home power ?? Anybody know about that.
permalink,
I have a bosch 125x plus extra parts for sale if you or anyone else you’ve talked with regarding your tankless water heater is interested. For a good price.
Please reply,
Thanks, Mark…
Try moving the BLACK chassis ground wire from the controller directly to the metal chassis, instead of it sitting on the top of the plastic control unit retention screw. Since I attached the BLACK chassis ground wire directly onto the metal chassis, the pilot ignition and timing has been greatly improved with direct contact to the chassis. I have spent endless hours trying to figure out how to make our Aquastar 125 HX tankless heater more reliable. Providing you don’t have any other component issues, this mod. may do the trick for you as well. : )
