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 Rinnai Tankless Error 12
Author: manumurf (CA)

A 4 year old Rinnai tankless started coming up with error 12. I can hear the gas light but it won't stay on and lit. We have another unit on the same gas service and it still works fine so it's not the supply of gas. My guess would be the a valve or thermocouple that holds the valve open. Anyone have any experience with this type of thing?

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 Re: Rinnai Tankless Error 12
Author: Scott D. Plumber (VA)

12 means the flame rod is losing it's signal. It has flame, and then does not. You sould go to the website and do a dealer search. Get an Authorized Service Provider to come figure it out. It could be a lot of things. And it still could be gas related or it could be a bad gas valve. You need to have a trained person trouble shoot it. They will be bale to figure out what is causing the 12, why, and fix it.

Usually if you do have a bad gas valve, there is a cause (like improper venting) that damaged the valve. Have it checked out.

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Give your kids a great start on the future! Encourage them learn a trade. Even if they go on to do other things, it's always nice to know that they have something to fall back on. Call your local technical training center or trade school to learn more.

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 Re: Rinnai Tankless Error 12
Author: manumurf (CA)

It happened occasionally in the past, I usually just pop the relief valve to get the flow going and it starts up again and runs. Not this time though.

This is an outdoor model and has no venting other than the exhaust output port on the front.

I flush it about every 6 months or so. Maybe I should spring for a professional service call.

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 Re: Rinnai Tankless Error 12
Author: Scott D. Plumber (VA)

I highly advise it. It is my guess that you have a gas issue that has been there from the start but only recently began showing up. I've seen many run for a couple years when gas was not done correctly only to start having trouble later. Just because it's running, does not mean it's running correctly and sometimes it can take a while for a problem to show up.

I'll give you an example: I found a entire neighborhood of about 200 homes gas piped with 3/4" CCST...the whole gas pipe system was 3/4" CSST! The run was about 60' long at the longest and was serving a 199,000BTU tankless, Gas furnace at 90,000BTU, Fireplace at 36,000BTU and a gas stove at about 60,000BTU! THe heater had worked for two years before the problem started. My peers here will tell you at a glance what the problem was and this was done by a so called master plumber!

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Give your kids a great start on the future! Encourage them learn a trade. Even if they go on to do other things, it's always nice to know that they have something to fall back on. Call your local technical training center or trade school to learn more.

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 Re: Rinnai Tankless Error 12
Author: manumurf (CA)

I took off the cover and cleaned out some cobwebs and dust, opened the relief valve again and it worked. Put the cover back on and it's still working fine after several days.

When you say gas valve, are you referring to the one in the unit or the on off valve the plumber installed to shut off the supply below the unit?

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 Re: Rinnai Tankless Error 12
Author: Paul48 (CT)

Scott....Isn't it recommended that they be serviced annually? Dust and cobwebs?

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 Re: Rinnai Tankless Error 12
Author: Scott D. Plumber (VA)

Paul, It depends on who you ask really. It's like anything else; there is no "Required" maintenance however if you do have it serviced it will make nuisance problems less likely and should make it last longer. I’m all for maintenance plans on things like these but I have to admit, I’ve not touched mine since installing them 6 years ago other than to clean the incoming filter. If properly installed the units are usually VERY trouble free. The problem is many are installed incorrectly by people who don’t want to pay for a professional, of by a professional who is too smart to read the instructions or take a training class. I can’t tell you how many I have seen installed by our brethren who did not do it right.

Manumurf, I doubt that dust or cobwebs caused your 12. It will be back. Did you have it installed by a trained, preferably licensed and certified Installer? If not I’ll bet you the gas supply is not right and you have not told us anything about the venting. Both of these done incorrectly can lead to problems like a code 12 down the road. Just because it “Ran fine” does not mean it was running right. Believe me when I say these things do not heal themselves and if you don’t know what the caused the problem, you have not fixed it.

I highly recommend you find yourself a local Rinnai ASP as stated above and have it serviced and checked out. I understand not wanting to spend money right here at Christmas but it beats having no hot water right here at Christmas. I have said over and over Tankless water heaters are not DIY projects. Trouble and fixing them certainly is not either other than cleaning the water filter. If you need another reason I’ll add this; if the cause of your 12 is the gas valve (The one inside the heater) is damaged by improper venting, that will also cause heat exchanger failure usually a few years after installation. The cost to repair may be as much as replacing it with another heater. Some things are not worth cutting corners on.

Best of luck and Merry Christmas!

- - - - - - - - - - - - -

Give your kids a great start on the future! Encourage them learn a trade. Even if they go on to do other things, it's always nice to know that they have something to fall back on. Call your local technical training center or trade school to learn more.

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 Re: Rinnai Tankless Error 12
Author: manumurf (CA)

I don't see how the venting could be improper. It is an outdoor unit, meant to be mounted on the outside, there is no "venting" involved. The exhaust from the burner comes out a slot on the front of the unit. There is nothing to attach venting to.

My other unit is a Noritz and it does have venting up through the roof. I don't have any trouble with it and it is basically installed the same way, except it is vented. Same LP Gas supply through the same regulator at the tank, 3/4 pipe all the way to the unit(s). The Rinnai is probably 20' from the lp tank, the noritz is 120'.

The gas man said the volume should be enough to run both units and my barbeque at the same time if I wanted.

While the installer was not "Rinnai Certified" the instructions were read and followed with regard to pipe sizing and unit placement to make sure it was far enough away from air vents and windows and things. Electric work was done by a licensed electrician.

If it happens again I will probably call someone and pay the $80 but not while it is working.

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 Re: Rinnai Tankless Error 12
Author: Scott D. Plumber (VA)

Ok Forget the venting thing. That was more for others who will read this. As far as gas guy, no offense to him, but I can tell you several stories of gas guys who said everything was fine, like when 2# gas was going to one or when the meter was the right size but really was only half of what was needed, or a regulator failed (Had several of those) etc etc. And it's very possible that the Rinnai gas valve is malfunctioning. Would not be first time as these things are still made by humans like everthing else. Let us know how you make out. I am very curious now.

Merry Christmas!

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Give your kids a great start on the future! Encourage them learn a trade. Even if they go on to do other things, it's always nice to know that they have something to fall back on. Call your local technical training center or trade school to learn more.

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 Re: Rinnai Tankless Error 12
Author: LemonPlumber (FL)

See the dust dirt over the sensor?what is the last high limit on the electrical?

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 Re: Rinnai Tankless Error 12
Author: manumurf (CA)

I did have a certified Rinnai technician out yesterday because it happened a few more times. Unfortunately it was working again when the guy showed up.

He checked the "Flame rectifier rod" and cleaned that even though he said it wasn't in need of it. Checked the gas pressure and tested for pressure drop above and below the valve in the unit and that was all fine. Tested the electical system and it was normal he said.

He spent about 45 minutes on the phone with a tech at Rinnai and then took off the covers of the burners and checked for debris and condensation where there should not be any. There wasn't.

Basically, he said everything checks out properly and looks very clean and it should work without trouble. The only thing he said that might be causing the 12 error(he told me the person at Rinnai suggested this) is some small amount of feedback through the neutral or ground from a running electric motor(like in a refrigerator or heat pump)that interferes with the signal to and from the flame sensor. He suggested unplugging the refrigerator or turning off the heater if it's running the next time the problem happens.

So, after an $80 contribution to the local economy, I am no closer to knowing what the problem really is.

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 Re: Rinnai Tankless Error 12
Author: manumurf (CA)

I tested it several times over the weekend and it worked every time. My daughter that lives in that unit was away for the weekend. Even when it's been extremely cold (for California) like 28 degrees, it's worked fine. Maybe it was just the cleaning of the "flame rectifier" as he described it, but he did say it did not look bad at all.

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 Re: Rinnai Tankless Error 12
Author: manumurf (CA)

This problem had been limited to the Rinnai in my daughter's little flat, now the Noritz tankless on my house(which is a few years newer than the Rinnai) is having the same problem. Intermittent flame failure. Won't stay lit. Error 12. The 200 gal LP tank is down to 40%. I am wondering if that is a problem since now BOTH units are having the same intermittent problem. The only thing they have in common is the gas supply. The rinnai is a bout 25 feet away from the tank and the Noritz is about 100. They are on 2 different electric meters and systems too.

As I said a few weeks ago the Rinnai Certified Tech could not find anything wrong with that unit in 1 1/2 hours of testing and stuff.

I am going to try to get the gas supplier out to test the regulator and put some more fuel in the tank and see if that works better.

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 Re: Rinnai Tankless Error 12
Author: ISOBARZO (AZ)

hi, I have rinnai R85-e outdoor propane, everybody said that error 12 means flame fail and try to resolve the problem checking gas, power or flame issue. I discover another area totally different. THE WATER FLOW (GPM). my heater is in error 12 when the shower is in use. when I check on the sink or lavator, works fine because their fauceTs are for less g.p.m. than the shower one. when I open the shower ONLY 50% to have less gpm. the error disapear.

check your heater's gpm range. and install all your faucet and shower tube heads with the same gpm not less not more. you must to be in the range.

don't forget if the faucets filters are plugged with water calcius salt or rust residues, the heater will fail also/ I'M SORRY FOR MY ENGLISH GRAMMAR. I'M NOT AMERICAN SPEAKER. thanks,

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