Bosch PRO Tankless 425 HN , main burner not firing

[Correy]

Aloha everyone, my water heater has been having trouble off and on firing the main burner. Wife is going to get rid of me if I do not fix it. I called the tech at Bosch, they no longer make it or service it, was connected to someone else.... long story short, they had me test the generator and I was not getting voltage from it, or my primitive meter was not picking it up. Probably that.
The iniginition spark sometimes happens and sometimes not, but when I assist with a BBQ lighter, the main burner still won't engage. The tech said it was the generator, a local service guy who did not want to come to the site said " it could be anything" but feels it probably is the control. Where can I source Orkli controls? PArt number 8 707 207 144.
Any leads from the Pro's?
Mahalo nui,
Correy on da BIG.

[Correy]

Update, and more info. I have the heater vented with double wall pipe, which leaks into the heater when it rains from the NW even after siliconing the seams and all. It has been raining hard. The control does not get soaking wet but I did see a couple drops of water on the control's chassis. I took the control off and removed the back cover. Let it air out, but there was no visible moisture inside. I did however get it to fire with the lighter along with the pilot both directed on the flame sensor and it did light. Shut off and tried a couple more times and it got better...... flame sensor maybe? 3 year parts warrantee just ran out last week...... go figure. Any thoughts?