Rheem Powervent water heater only runs for 12 minutes

[rc772]

Rheem Powervent water heater with hot surface igniter.

The water heater still works, but after running for approx 12 minutes, the burner turns off and the blower keeps running. Then it starts the hot surface ignitor for approx 30 seconds but the burner won't start again. It will keep trying this cycle of starting the ignitor, but no flame.

I unplugged it, and tried again in an hour, and it will work again for 12 minutes, then turn off the burner, and start the whole cycle again.

I did notice the hose on the blower was cracked, and I cut off the bad section and reattached it, however this did not help the issue.

What are the possible issues causing this to occur? What could I try to troubleshoot next?

Thanks for any suggestions!

 

[rc772]

So it's been a few days since I've only been able to run the water heater 12 minutes every hour. But today it ran for 30 mins until I stopped it because that was strange behavior. I'll see if I can get it to run 40 minutes next time... that should be more than enough hot water needed.

 

[Mitchell-DIY-Guy]

Did you check your exhaust line for possible obstructions?

 

[rc772]

I'm not sure the correct way to check. I did go outside where the vent exits the house and there is a very good flow of air coming out from the start of the 12 minute cycle til past the point where the water heater turns off. So there is no change in air flow at all from when the flame is on and even after the flame is off the powervent will continue to blow air just without a flame, until I unplug it.

 

[Mitchell-DIY-Guy]

If you’re getting a good flow of air during a cycle, then you probably don’t have a blockage, but the way to check is simply disconnect the piping and snake it out. I found a tennis ball in mine once.

 

[rc772]

Thanks for the suggestion! I'm assuming that since the air flow stays constant through the whole cycle that it's not the issue, and that some sensor is getting triggered at the 10-12 min mark. I'm just not sure what sensor or part to check first.

 

[rc772]

Ok, I tried cleaning the flame sensor with sandpaper today... but no luck there, problem still persists

 

[Mitchell-DIY-Guy]

Just out of curiosity, have you tried calling Rheem Technical support, if such a thing exists? There may be a defective part, but that part might not be available anyway. With the cost of many plumbers today (around here you can't get one out of bed for less than $125, and the hourly rate is generally higher) the cost of further diagnosis might be more costly than replacement. That's so true with many things today.