DSI suburban hot water tank - shut off

And that spark electrode is also used to 'prove' main flame
When the main flame ignites it generators a milivolt signal back thru spark electrode to circuit board telling circuit board I'M LIT. Circuit board then keeps power on gas valve keeping it open until t-stat opens killing circuit.

The spark electrode has to be engulfed in main flame
The spark electrode needs to be clean of carbon/soot
The spark electrode needs good/clean tight ground (the screw that holds bracket in place is the ground source)
The spark electrode ceramic can not be cracked
The spark electrode high tension wire needs good/clean tight connection to circuit board (wipe it down with a rag sprayed with silicone also).

AND the combustion chamber/exhaust tube needs to be clear of ANY obstructions

IF you still have problem with main flame staying lit.....then circuit board is bad

ScottG wrote:
Use a BRASS brush to gently clean thermocouple/flame sensor.

Scott - don’t have thermocouple/Flame sensor. I have DSI. It runs with electronic that will ignite flame when it needs.

Roman Duck wrote:
First, clean your burn tube. the smallest cobweb can deflect the flame, causing the flame out. If that doesn't work have the circuit board tested. Had same problems that we had, 1st time was dirty burn tube. Cleaned the tube and was good for the season. Following spring had same problem, wasn't the burn tube. Brought it in had it checked, board went bad. Replaced the board and works great.

Yes I did clean the burn tube with flexible brush. I even let orifice soaked with 90% rubbing alcohol. I pressed reset button. But it came out the same problem. The last thing I will bring circuit card to have RV tech to test it.

Use a BRASS brush to gently clean thermocouple/flame sensor.

First, clean your burn tube. the smallest cobweb can deflect the flame, causing the flame out. If that doesn't work have the circuit board tested. Had same problems that we had, 1st time was dirty burn tube. Cleaned the tube and was good for the season. Following spring had same problem, wasn't the burn tube. Brought it in had it checked, board went bad. Replaced the board and works great.