I installed a Bosch 125FX natural gas water heater in my home in 2005.
It has been working well up until a month ago. On one day, I noticed
there was no hot water at the kitchen sink. I turned the faucet off
and then back on again and everything was fine. A few weeks later, it
happened to my wife when she turned the shower on. A few days later
it happened again while I happened to be standing near by the heater.
The heater goes through its normal "tick, tick, tick" but the burners
never ignite. Water flow through the heater is normal and, clearly,
it tried to start. I figure it is one of two things:
1. The igniter stopped working inspite of the ticking sounds
2. The gas valve isn't opening so there is no gas to ignite
This only happens one out of ten or twenty uses so the temporary fix
is a quick off-then-on with the faucet. Being busy (and lazy) has
kept me from investigating further. Do any of you have any experience
with this model? Is there a common failure that causes this