Question about Rheem RTG-74PVN-2 Natural Gas Pronto Whole House, Natural Gas, Tankless Wat

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C2 11 code, same problem as others. Used to be hvac tech. Gas fine, vent fine,grounded properly, tore unit apart and inspected and cleaned entire thing. Looking for new ideas, what has worked for others.

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To JZKlipper, you probably were snowed on the needed part. This is a known issue with these units, and the dustier the area is that they reside the more often you will have the same issue. Most likey, the machine needs maintenance. I had the same issue and tried all the "fixes" I could find on-line and more. Called the company (Rheem) and they sent me out directions on how to perform a clean-out of the gas fire plate on the inside of the unit. This should be performed by a trained professional if you are not extremely handy. It took me about 2 hours to complete the procedure. This will correct the problem.

Posted on May 25, 2011

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I had the same problem with my Paloma a year and a half after installation...contacted Rheem customer service (800-432-8373) and they recommened a local installer in my area. The technican diagnosed the problem as the "flow control valve"; he managed to get Rheem/Paloma to cover the part under warranty...I only had to shell out the money for the install.

Posted on Nov 17, 2009


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RTG64DVN TANKLESS water heater brand new after install god a code 11 (gas valve not all the way open) and smelled gas when we would open faucet..replaced with new 3/4 line still have the 11 code and smell...

Your gas is not being burned completely. And you are getting code 11.
These may be 2 different problems, or more, related to gas supply, incoming air, venting, electric, dip switches, product defect ... which does not leave much off the table.

Code 11 is can also be wrong gas, wrong gas pressure, incorrect grounding, wrong size gas meter, and/or gas regulator.

Gas supply:
The tankless unit has BTU rating on label.
Get a hold of gas company to look at meter sizing, and pressure, to see if the meter is correct size for whole house line demand. And gas company may red tag your water heater. For good reason, until a professional validates installation.

If home has other gas appliances, and meter is undersized for additional demand from tankless, then that can damage some appliances.

Dip switch and gas type:
Ask Rheem if your model matches the type gas you have: Natural gas, NG, and propane, LP, are different, and some tankless models work with either type gas depending on dip switch setting.

Dip switches and altitude
Ask Rheem if the dip switch setting on your model matches altitude above sea level. Different altitudes can require different dip switch settings.
If untrained person messes with dip switches then that is a risk.

Check 120V outlet for correct polarity ... and full voltage with 80% rating on tankless nameplate ... and check grounding to unit, ... and electric line should be dedicated, and main box should have whole house surge protector to avoid power surge knocking out electronics.

Air and venting:
Inadequate venting can also cause incomplete combustion of gas ... since the unit takes bigger incoming gas line, it is logical that unit will also breathe in more air and blow out more combustion byproduct. Is the vent sized correctly? Are there obstructions in the vent, such as several bends or turns? Is there adequate incoming air supply?

Defective product:
Malfunctioning unit, bad sensors, defects, bad pc board, there are a lot of reasons unrelated to code 11 that can be causing problem.
But if you installed yourself, it can invalidate product warranty.
There was a guy who had similar problem, and sent unit back to Rheem, and they hooked it up and detected no problem and sent it back ... end of story ... guy never got it working and lost his money.

Warranty and explosions:
Rheem does not recommend installing tankless yourself because there are many potential problems, including voiding product warranty and/or blowing up house.

Gas appliances are dangerous. Inexperienced handyman should not do this installation without extensive reading about the myriad of mistakes other people made... that professionals tend to be aware of ... which is called experience.

Validate your installation:
to preserve warranty and avoid explosion:
Call Rheem to find qualified service tech located nearby who can look at installation while talking to Rheem on phone.
Your installation needs to be validated.

Since your unit requires yearly service, its good idea to find local service tech who will gladly take your money each year.
If area does not have qualified service tech, then do not install tankless, because the problems can be endless and without solution, and generally you can't fix the thing yourself. I answer questions on fixya. I see it.

Because tankless are generally not DIY, many problems are avoided by having professional installation since Rheem tells customers to contact the installer... a lot of help Rheem is ... but you are connecting a complex computer chip with sensors to 120 volt household wiring that has not been checked for polarity or correct voltage or line interference, and connecting to a gas line and burner with vent to outdoors. All these systems pose problems for tankless installations.
On top of inherent risk of gas appliance, which should only be installed and maintained by trained professionals.

Jan 31, 2013 | Water Heaters

1 Answer

Gas thermostat fails

1) If your water heater plugs into outlet, then electronic gas controls are susceptible to power surge. and reversed outlet polarity, and undervoltage at outlet, lack of ground wire continuity between ground plug and manifold tube connected to bottom of gas control valve.

2) If sediment builds up inside tank, it will cover thermostat probe and cause probe to malfunction.
Tank can have sediment flakes build-up and still drain perfectly clean water.

3) There are 2 general types of Honeywell electronic gas controls valves installed on Whirlpool heaters.
The gas control for atmospheric water heater (passive vent at top of heater) is modular, and is not always removed from tank when replaced.
The other gas control for power vent models is removed completely.

4) Remove thermostat from tank to reveal 3/4" opening.
Look inside tank.
To remove sediment flakes: Tape assorted plastic pipes and tubes to shop vac hose and see if flakes can be removed. And remove drain valve.

5) Check that air intake is clean using feather duster or compressed air, clean combustion parts as shown in product manual. If air intake is clogged with dust, then draft vent is slowed. This causes slowed venting of hot combustion by-product that will overheat combustion chamber.
Typically this condition will trip the FV system. BUT it might also trip the gas control thermostat.
Stand 3-legged water heaters on bricks so inspection and cleaning flame arrestor screen is ez.

Oct 30, 2012 | Water Heaters

1 Answer

Rheem-Tankless-water-heater I am showing a C2 then 11 flashing on my thermostate. what is wrong.

Before calling service technician, open following links for common error codes, Rheem chat, and possible manual.

Error codes are start point for troubleshoot.
C2 11 is 'no ignition' or 'gas shut off vale is not open'
Gas shut off valve handle must sit parallel with gas line.
This kind of error code can be air in gas line, improper grounding at electrical outlet, bad igniter, shorted solenoid, loose connections, etc.
Most tankless manuals recommend yearly service, and that type of work usually covers cause for most common error codes: for example checking gas pressure, gas line, air in gas line, clean and check burner and combustion parts and igniter, inspect that vent condensate is properly draining and vent has good draft, clean water filter, clean air intake, check for loose wires, delime heat exchanger, test outlet with circuit analyzer etc.

Aug 11, 2011 | Water Heaters

1 Answer

My paloma tankless gas has a error code c2 11 c4 12 why

Open following link for useful troubleshooting information:

Error code 11 is 'No ignition'

Ensure you have gas to the appliance.
Ensure gas type and pressure are correct.
Bleed all air from gas lines.
Ensure gas line, meter, and regulator are sized properly.
Ensure appliance is properly grounded.
Check gas solenoid valves for open or short circuits.
Ensure igniter is operational.
Check igniter wiring harness for damage.

Error code 12 is 'Flame Failure'
Ensure you have gas to the appliance.
Ensure gas type and pressure are correct.
Bleed all air from gas lines.
Ensure flame rod wire is connected.
Check flame rod for carbon build-up.
Ensure gas line, meter, and regulator are sized properly.
Ensure appliance is properly grounded.
Check gas solenoid valves for open or short circuits.
Check power supply for loose connections.
Check power supply for proper voltage and voltage drops.
Disconnect remote control.
Disconnect and re-connect all wiring harnesses on unit and PC board.
Ensure proper venting material was installed.
Ensure condensation collar was installed properly.
Ensure maximum vertical vent length does not exceed allowable limits.
Ensure maximimum horizontal vent length does not exceed allowable limits.

Range of causes are part failure, gas pressure loss, air in gas line, improper installation of gas line or vent, 120V power to unit is disrupted or unit not grounded, circuit problems, venting problems, remote control, wiring to PC board, board failure, carbon build-up on flame rod, short circuits on gas valve solenoids.
The fact that you have error code tends to eliminate your plumbing as culprit, the error code does not mention air supply, otherwise it looks like every possible cause is on the table.

Add a comment with your experience so other with same-similar problem can benefit.

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Fixya is always less expensive than a service call.

Mar 25, 2011 | Rheem Tankless Hot Water Heater...

8 Answers

Error code 13 (air flow) tankless H20 Rheem

Have 2 of these Rheem units in my house. Both had this same error code within 30 days of each other. And my neighbor has 2 units as well - and guess what - 2 months after mine stopped working because of the code - so did theirs. It is not something that can be fixed. It is a manufacturer's defect - and it looks like Rheem has yet another class action on their hands (like the one for the RTG - 74 PVN). They need to do a recall to repace these units.

Jan 17, 2010 | Rheem RTG-74PVN-2 Natural Gas Pronto Whole...

5 Answers

Tankless water heater error code 11

I was having the same problem untill I reallized it was my venting system. Test the water heater with no vent on top. Disconnect the vent pipe from the water heater and try turning on the hot water. the water heater needs a special adapter to vent the direct vent water heater. One other thing you can check is the gas pressure in your home. You have to have between 7 and 8 WC (water Column) for the tankless water heaters. You can call your gas supplier to find out what you have.

Apr 12, 2009 | Rheem RTG-66DVN Direct Vent Natural Gas

1 Answer

What does a "12" on my 96-140 F Degree Control mean?

I'm mr.grzz, thanks for your question,
A code 12 on your control pad has allot of different remedy's, here is a list,
First it means you have flame failure,
Check to make sure the gas is turned on at the unit, the meter, or tank,
Check for obstructions at the flue outlet,
did they check the gas pressure ?
was the gas line properly sized ?
did they use Rinnai venting materials and was it properly installed ?
was the condensate collar installed properly ?
did they double check to make sure vent lengths were well within limits?
did they verify the dip switch settings ?
is the unit properly grounded ?
check power supply for loose connections
check power supply for proper voltage and voltage drop
check to see if flame rod is connected, this would be my guess as to what your trouble is, flame rod could be out of alignment as well, not sensing the flame, the other thing would be the gas, air in the line will cause this too,
the flame rod needs checked for carbon build up,
I know thats alot of tech data, but for all intents and purposes it would be best if you called a service tech that is certified with Rinnai to come take care of you, if you call them tell them you have a code 12, and you have the possible causes, I hope this was of help to you, please write us back and let us know, again thanks for your question, mr.grzz

Jan 21, 2009 | Rinnai Digital Remote Water Heater Control...

4 Answers

Rinnai tankless water heater code 12

12 - Flame Failure or Poor Ground

1. Immediate code 12 is usually a defective gas valve, power supply problem, or defective fan motor wiring harness.

2. If code 12 occurs after a few seconds it indicates that proper operation was established, but then stopped unexpectedly.

3. Verify that fuel is being supplied to the unit.

4. Check for proper electrical ground. Unit must use a grounded power supply.

5. Check for flue blockage on inlet or exhaust.

Dec 31, 2008 | Rinnai Webstone The isolator EXP tankless...

7 Answers


the A3 & E3 codes are for the back flow sensor on the heater. Could be disconnected or a bad sensor. Call bosch tech support and they will help you with this.

Dec 30, 2008 | Bosch AquaStar 2400ES-NG

7 Answers

Rheem RTG 53 PVN with fault codes C4 or C7

I had the same problem with my tankless waterheater (flashing c4 76 alternately). I called Rheem
tech support and they had me 1 power down the remotepanel 2 unplug the unit from the wall 3 remove the cover 4 remove the wires for the remote panel from the circuit board and pull the twisted pair that goes to the remote out from the bottom of the unit. 5 reinstall the cover 6 plug the unit back
into the wall and turn on the hot water see if it works. It did in my case and they are sending me a new remote panel. I hope it helps.........

Nov 21, 2008 | Rheem RTG-53PVN Indoor Natural Gas...

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