Rheem tankless water heater error code 12 burner cleaning

Was receiving intermittent error code 12. burner was very dirty... time will tell.
Please let me know if the full burner should be staying on.

[ScrapMetalWorks]

I can confirm that after a month and a half of use the problem has not repeated. I am astonished that cleaning the burner is not mentioned in the troubleshooting guide as a possible fix when error 12 occurs. It is also hardly mentioned in forums or YouTube. This one issue is probably what gives instant water heaters the bad name of being unreliable when they just need regular maintenance. Given the complexity of removing the burner, not difficult just lots of screws, I won’t be doing it every year as I do the vinegar back flashing but I’ll just wait for the first error code 12 to come up which I’m guesstimating to be 2-3 years depending on use. In fact it would be nice if these water heaters have a built in hours counter to keep track of use and a recommended preventive cleaning frequency. Happy cleaning!

[Raj-mzeh]

Thank you for taking the time to make this video. I followed all the steps in your video. Cleaned, vacuumed and used fine sandpaper on the three rods. I didn't really do anything significant but it has been a week now with no more error code 12.🤞

[charlesschmidling]

Having intermittent Code 12s for about a year. One or more off-on cycles would correct the problem. Was going to follow your video to disassemble and clean my LPG Rheem. Found a different video that just required cleaning of the flame rods. Gave it a try before taking my unit apart. It's been a day but so far so good. Keeping your video around just in case.
And yes, when the demand is past a certain threshhold, both sides of the burner fire up. Turned bathroom sink on, got half the burners. The bathtub got both sides.
Thanks for explaining this cleaning option.

[spottymaldoon]

Extremely useful. Not a job for the faint-hearted - it's surprising that such large pieces of debris can get inside the unit. I have had an older version of this and it has served for around ten years but lately showing the error code 13 when the water demand gets too high. Cleaning the flame-rods helped in the beginning but now I see I have to jump in and do what you did! Thanks for the very clear explanation - I shall be careful to identify which screw goes where and shall hope the gaskets aren't damaged when I disassemble. By the way, I will definitely buy Rheem again - we still love this unit!

[karlthieme]

Thank you for documenting this. My Rheem RTGH-95DVLN had been doing code 12 intermittently for over a year and we would just shut off the hot water to let it reset and then turn the hot on slow to get it to stay lit. Over the last year it changed from intermittent to consistent. If the tub or the washing machine was turned on full hot we would get code 12 anytime that there hadn't been a recent use (in the last 30 min) of hot water.

Yesterday after watching this video and one other, I went home on my lunch hour, took it apart and blew out the burner with an air compressor. There was an amazing amount of white oxidization in the burner fins. I might suggest a face mask if I had it to do again. Now no more code 12 despite deliberately doing the things that very predictably would cause it before.

Regarding the right hand side of the burner not staying lit: When I have the tub filling full blast hot-only, both sides light up but when the hot water flow is less (like the kitchen sink) only the left side is lit. This appears to be an efficiency feature operating as designed.

[danljohnston]

I am the proud? owner of 2 of these high maintenance water heaters. Replaced 1 after working on it for 10 years. Seems you have to be a to keep these thing working. If this is you first time cleaning it, I'm afraid it won't be your last. I don't think other brands are much better, but I hope they are. Got to say Rheem is good about handing out parts under warranty. Where I live (rural) there are no service people close, so DIY is my only option. I wish I had a video several years ago, so I'm sure your video will help many. Having said that, tearing into these complex machines is not for the average homeowner. Thanks for posting.

[nadreggid]

Great vid. Hey, why can't the safety plastic thermo sheets be replaced? I have a nice heater with one burnt spot that I have heard I must just throw away. That hurts my feelers.

[jimdesmond]

I had code 12 issue about a year back. Cleaned off flame rods and haven't had the issue again until this year, so adding to annual maintenance. Also, your blue flame issue is by design, 2nd side fires up on higher demand.

[onfus]

What a pain to do - but great video. Not loving how high maintenance these things are - and purposely designed to be difficult- but not running out of hot water keeps the family happy.

[joelridley]

Thanks for the video. I have the high performance model. The flame sensor had to be replaced after 2.5 yrs but was under warranty. Rheem tech was very good over the phone. Starting to get error 12 only when I require small quantities of hot water. i.e. rinsing dishes in the sink. When I need larger quantities, like in the shower, never experience an error 12. So I am thinking that it is a build up on the flame distributor as you showed in this video. I hope my unit is as easy to take apart and clean.

[andyfinck]

Only half of the burner stays lit unless the demand is high. ie shower and washing machine on at same time. Great video!

[hokudadog]

Great video, thank you! I wasn’t able to see the debris clogging the burner, but I appreciate the effort you made on this

[hanssenjones]

Im not a plumber but I do sell plumbing supplies for a living and I believe I know why it is doing this. These are designed to save energy. What the manufacturers do is only use part of the burner when you have low flow (one or 2 faucets running) and when you have higher flow like dishwasher, shower, and a sink then the complete burner should fire off. Hope this helps. thanks!

[albino]

I had the codes error 12, and sometimes 13. I cleaned the two left side flame sensors, and it has been working really good now, for about 3 months

[joshklingelhofer]

I think you did a great job. thanks for sharing!! And the gpm or gallons per minute is what brings on the other part of the burner.

[MacPC]

Code 11 or 12 - clean or replace both flame rods. You also have a problem with your igniter it it clearly visible that high voltage is escaping through the insulation.

[RandyHermann]

Thanks for all of the advice above. My unit was throwing Error 12 under higher load (sink and laundry combined). I cleaned the manifold but not the burners and reassembled. The unit then started throwing error 13 after about 30 seconds under any load. Cleaned the intake screen- it was filthy, and still had the code. Double checked the system and realized I had not reconnected the power to the small transformer attached to the gas system, located just to the right of the top right corner of the circuit board. Reconnected the power and everything works perfectly. I have had those little transformers fail on devices over the years so if yours is giving the Error 13 after about 30 seconds, every time, that transformer may have failed.

[lilichen]

I began getting error code 12 after a power surge but cleaning out the flame rods did not help. I'm thinking it might be the control board or fan got damaged but the unit will turn on periodically before going to code 12.

Was your unit working when you changed out the control board and fan?

[NewWorldDAO]

Hey how do you clear out a frozen hose? I think that is what I have. It is -5 degrees here in Park City. Thanks

[vette]

I had a code 11 and it turned out to be clogged gas manifold ports. Rheem techs never mentioned this to me or the installer. Works great now. Unit is 7 years old and heats the floor in my garage. Rheem techs should have known. Kept telling me to replace parts even though they diagnosed fine.