Rheem error Code 13 Solution

Kudos to the Rheem technician (800-­432-­8373) for pointing me in the right direction. After 1 year of flawless operation we began experiencing sporadic "13" error codes causing us to reset 1-2 times per day. Once I got past the original tech suggesting a multitude of lame reasons, I was transferred to a real tech who suggested examining the FLAME RODS (thermocouples) for deposits and use either steel wool or fine grit sandpaper to remove them if present.

Sure enough, one of them showed deposits and now we're back to operating reliably. These tankless units appear to be over-engineered and prone to sensor issues after prolonged use which leaves consumers with a bad feeling about their unreliability. I greatly suspect examining and cleaning the FLAME RODS would solve the majority of code "13" issues.

I've had to clean them with my furnace every few years and found them more accessible and a simple fix. Accessing them inside of the tankless unit is not as simple, but proved just as effective. :)

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Mar 02, 2022
Richmond on demand code 13
by: Levi Trautman

I’m a service tech of 17 years but this kicked my a$$. I worked on Navien and Rinnai plenty of times before with no problems fixing. I installed Richmond in my own house since the price is very reasonable. I had code 12 show up, so I cleaned sensors every other week, then replaced them, and that was better for a few weeks than code 13 appears.

I pulled burners, cleaned them, they were not bad, everything looked good and was only installed for 7-8 months. Put back together... code 13 again grrrrrr. I called Rheem, and we went through everything from pressure to sensors and proper installation - all was good. I even flushed the unit with vinegar but was not necessary though, it was clean.

They gave up on the phone and were going to send a tech out from the HVAC company that installs Rheem, Ruud, and Richmond. Of course none in my area, so they said hire someone and they would reimburse me. I called 3 other companies after explaining what I’d done already and no one would come. Finally, I pulled the gas valve and orifice plate out of the first port closest to the gas valve. I had not got the port cleaned enough last time so I took apart a used piece of welding wire to clear the port and that took care of the problem.

Hopefully, this helps someone else!

I still had my old water heater in my house and this took weeks of messing with it to figure out. And the funny-looking thing on the bottom of the gas valve with an adjustable dial goes to a diaphragm like an accelerator pump on a carburetor - just FYI.

Dec 30, 2020
Code 13 solution
by: Anonymous

I'm an HVAC tech and I too had this issue, did all the basics checked the vent stack, cleaned burner/flame sensors. Still, code 13, Rheem was no help all gas pressure was normal, what I noticed after a small power surge the code 13 issue came about but nothing changed, well something did the setting in the plc/ board. I noticed the fan speed not kicking up as high as it would normally, so on the board under the dip switches there are 3 buttons low fan speed, high fan speed limit and adjust button, I held the low fan, and the adjust button raised the low fan speed up 4 points and the same to the high speed and guess what... Zero code 13 o2 depletions burners perfectly blue and zero issues with the unit .. Hope this helps you solve this Rheem phantom issue.

Jan 22, 2020
Code 13
by: Joe

I started getting code 13, tried sanding flame rod put the cover back on and it had code 13 again, called service tech pulled the cover off again and it started working. Service tech said it looks good may want to replace flame rods and he left (without putting the cover back on) sure enough I put a cover on and it has code 13 again.

I ordered flame rods, put them on working like a champ, put the cover back on and code 13 again!

The fresh air intake is clear, can’t figure out what is causing this?

Nov 30, 2019
Rheem ECO-180 LP
by: Efren

This water heater started to be a problem, 6 months after I bought it. I have installed many tank & tankless water heaters as I am a plumber. I called the helpline and that's where the B.S. started. I was told to check the flue, gas, is it plugged in, who installed it. When I told them, I installed it and I was told that's where the problem could be. I told the little turd that I was 55 and I have been plumbing since I was 16. Not once did he tell me that codes 12 & 13 are a constant problem with these W/H. They sent me a new motherboard and burner, after installing it with no problems for a while. Then it started again, so I know that most problems are gas input thermocouples, diaphragm and so every 3 months I clean the burner, igniter and thermocouple.

May 12, 2019
Code 13
by: LD

My Rheem has thrown a code 13 several times now. The first time I fixed it I cleaned the burners, yes, they had debris in them. A year later it started throwing the code 13 again. This time I built an airbox/filter for the incoming air. I cleaned the burner again; a lot of debris in it. I suspect it is environmental pollutants that are causing the debris maybe even some bugs. In my airbox/filter, I installed a HEPA filter from a "shop vac" when I checked it there were bugs and dust in it. I took some pics but no way to upload them here. Why doesn't Rheem offer an incoming air filter?

May 10, 2019
Error Code 13 Transformer!
by: Anonymous

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.

Feb 19, 2019
Err Cde 13. Northern Serv Home Group
by: Barry

I have a Rheem RTGH 95-DVLN unit, that worked great for about 4 years. Then the infamous Code 13 came up about 3-4 months ago. It gradually became more frequent. I did the flush routine of unit....... No Help........... I searched the internet and didn’t find much information on......except this site.........I did the flame rod cleaning........... No Help........... I cleaned the water strainer and was certain I found the issue, but........No HELP...............

Then I took the time to read further comments about the Northern Home Service Group regarding the problem with the Gas Valve assembly and need for cleaning. I went to the unit with tools, and I-Pad in hand, and followed the Northern’s instructions.................... After getting the unit apart, and taking numerous pictures, organizing screws............... I finally got the gas valve assembly out and on my workbench............. the little ports, and some larger ports, particularity the ones around the flame rod, where blocked. Or partially blocked. I took my hand drill set, and clean all of the ports...... reinstalled.........and what do you know............ NO problems...........

I really appreciate the Northern Home Service Group taking the time to complete this.........advice was right on.......

Thanks again.........Barry.......

I never called Rheem...............so.......no negative comments to their service. I just generally find these things to be of no help.

Jan 31, 2019
Fixing Rheem error code 13
by: Jim

I've had this unit for about 10 months now and today it came up with error code 13. I put a filter screen on the intake and it worked fine until now. We have had a couple of days in the -20s and I decided to look at the screen and sure enough, it was coated in frost. I cleaned it off with a broom and so far it seems to have corrected the problem. I can see that if you don't have a screen, debris could get sucked in there and cause a similar problem.

Jun 29, 2018
fixing rheem error code 13
by: Anonymous

Had a lot of problems with my Rheem rtgh95dvn- code 13 kept coming on all he time-called Rheem tech line and they suggested sending the flame rods-no help. Called back and they gave me the number of a Rheem tech in my area. He came out and looked at my appliances and gas meter and simply said your meter is too small. I went out and saw my meter was a 250000btu meter. Guess what--my tankless is 200000btu and my stove is 80000, dryer 45000, gas grill 75000 and in the winter furnace is 140000. Add them up and you can see there is a problem if the dryer and stove are on when someone is showering do yourself a favor and see if this could also be your problem. Gas company came out and installed a 630000 meter no charge.

Jan 25, 2018
Not quite, hold the phone
by: Northern Home Service Group

The flame probes are NOT thermocouples. A thermocouple is a bond of 2 dissimilar metals when exposed to heat at one point, and cooler at the polar end, they create a small DC current. Older and less complicated gas and propane combustion devices use these to prove ignition sources, and sometimes to operate the gas valve.

A flame probe is an insulated steel rod which sits in the path of the flame which receives the milliamp current (dc)created when AC current passes through a flame. AC current rectifies as it passes through a flame as the electrons of an oxidizing fuel only polarizes current.

Ok, now that this is done- I’m glad that cleaning the flame probes helped you out. But your problem isn’t gone, and I’m sorry to say, it WILL return and cleaning the probes won’t help. Rheem/Ruud has not been forthcoming with the problem as found elsewhere on the inter webs. The repair is a bit more difficult but follow these basic steps;

Error 13- ignition issue sensed through improper combustion-
Shut off gas and water.
Unplug unit.
Open a faucet to relieve the pressure
Disconnect the gas from the bottom of the unit by removing the 3 screws holding the lower external brass gas connector.
Slowly rotate back and forth while delicately pulling down to remove gas fitting
Take photos of all wire connections to ease the re-installation.
Remove all small wire connections of the gas valve and pressure switch.
Remove pneumatic tubing from pressure switch at the base of the gas valve.
Remove the screws that hold the gas assembly to the heat exchanger. These screws are the ones around the perimeter of the gray sheet metal cover below the heat exchanger. Do not remove the screws from the shiny metal piece above the dull gray piece. The shiny metal piece is the one which the spark wire and your two flame probes connect to.

Once all of the surrounding screws are removed you should be able to delicately remove the entire gray assembly and gas valve in one piece. The backside of that gray sheet metal contains the gas orifices. The side left on the heat exchanger has a series of the large hole and small holes. If you look into the small holes you will see small dividers in each hole. Chances are the small holes are blocked up with a lot of debris. Usually, pollen lint and dust collect here. It is a design flaw.

By taking a stiff hi gauge wire like 18 gauge straightening the wire and putting a very very small hook on the end of one, insert the wire straight into the small hole rotate 90° and pull back. You will find debris comes out of the small holes. This process can be assisted with the use of a small vacuum in addition to the use of the wire.

Clear all of the small holes of debris and with a small high-intensity inspection light look into each hole to verify that all of the debris has been removed. The lower tray where the air comes into the burner cavity most likely has dead moths and other debris in it. Vacuum that debris out. Now reassemble the unit in the reverse order of disassembly starting with placing the burner plate back in place and re-connecting all of the screws. When you go to connect the pneumatic line back onto the pressure switch you may find that there is moisture in the pneumatic line. Drain that moisture.

Continue reassembling the unit. Prior to running the unit turn your water on the first. Allow water to run through the unit pushing out all of the air. Now turn the unit back on and restore to operation. When the unit first runs the burners will make a growling noise. This is normal as the stoichiometric ratio has been disrupted. It will return to normal operation. You will find that now your water temperature is easier to maintain and the unit runs much more smoothly.

On an additional note, the screws are very important. The proper screws must go back into the proper holes. You cannot lose the screws. A pro trick that I teach my apprentices is to use A number two Phillips head screwdriver with a drinking straw over the shaft. Cut the drinking straw to the exact length of the shaft. When you place the screwdriver on the screw make sure that the straw touches the wall of what you are pulling the screw out of. When you turn the screw out the screwdriver will back away from the wall in which the screw was mounted. Continue holding the straw up to the wall that the screw is being pulled from. This will assist in keeping the screw attached to the screwdriver and not falling. In addition magnetic screwdrivers are an absolute must.

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