Suburban SW6 lights but drops out after 30+ seconds
I'm a pretty good troubleshooter but this one has me going. My 10 year old water heater has been working fine but now will only light and run for approx 30 seconds + or - a few seconds.
a) Normal sequence to start up, 5 second wait, valve actuates, igniter lights gas, runs for 30 sec
b) I replaced the propane regulator incase the gas was dropping out or weak
c) Replace the igniter thinking it may not be sensing the flame is there (2 pin)
d) Checked the gas valve solenoids using 12vdc, they both work strong and click hard
e) While the flame is working, there is 12vdc present at the gas valve. When it drops out there is still 12 vdc present at the gas valve. Sounds like gas is shutting off inside valve but its not because of electrical shutting off ?
f) Took main circuit board to RV shop and it tested OK
g) Cleaned and checked all electrical connections on gas valve and main circuit board.
h) DC power is always 12.5vdc
i) Disconnected gas line from gas valve and at regulator and blew out with 30 psi air compressor, thinking oil might be blocking lines ?
j) There is no lp switch over, single tank with new regulator. I have tried another lp gas tank, same thing
I give up. I still think its a gas issue, either weak or blocked or the gas valve has some kind of mechanical shut off perhaps when gas is low pressure or it is just bad ? I don't think its going to be electrical since the gas valve still had 12vdc when iit shuts down. sometimes it will go right into the start up sequence after the flame goes out and relight immediately for a short time ?
Any ideas ?
a) Normal sequence to start up, 5 second wait, valve actuates, igniter lights gas, runs for 30 sec
b) I replaced the propane regulator incase the gas was dropping out or weak
c) Replace the igniter thinking it may not be sensing the flame is there (2 pin)
d) Checked the gas valve solenoids using 12vdc, they both work strong and click hard
e) While the flame is working, there is 12vdc present at the gas valve. When it drops out there is still 12 vdc present at the gas valve. Sounds like gas is shutting off inside valve but its not because of electrical shutting off ?
f) Took main circuit board to RV shop and it tested OK
g) Cleaned and checked all electrical connections on gas valve and main circuit board.
h) DC power is always 12.5vdc
i) Disconnected gas line from gas valve and at regulator and blew out with 30 psi air compressor, thinking oil might be blocking lines ?
j) There is no lp switch over, single tank with new regulator. I have tried another lp gas tank, same thing
I give up. I still think its a gas issue, either weak or blocked or the gas valve has some kind of mechanical shut off perhaps when gas is low pressure or it is just bad ? I don't think its going to be electrical since the gas valve still had 12vdc when iit shuts down. sometimes it will go right into the start up sequence after the flame goes out and relight immediately for a short time ?
Any ideas ?
