Richmond Tankless Error Codes: 11, 12, 29 and More

The Short Answer: On a Richmond tankless, the manual’s listed cause for code 11 is a gas shut-off valve that isn’t fully open; for 12, an interrupted gas supply or a low propane tank; and for 29 (condensing Encore models only), a clogged condensate neutralizer. Richmond’s manual allows owners to fix 11, 12, P1 and some 90/99 causes; every other code goes to a technician.

Which Richmond tankless do you have?

Richmond tankless heaters are built by Rheem, and the manuals linked from Richmond’s product pages are the Rheem editions. The code list depends on the product line, so check the model number on the rating label first.

The Encore L-Series (RMTGH-L199i) uses a different display and code list; use its own manual. Older Richmond tankless models no longer listed on Richmond’s site may also use a different chart. If your code isn’t listed below, Richmond’s instruction is to turn the heater off and call for service, not to guess from another model.

Codes in the Essential Plus and Encore manuals

These causes come from the error charts in Use & Care manuals AP22009 (opens in a new tab) (RMTG) and AP21820 (opens in a new tab) (RMTGH).

Code 11: check the gas valve first

The manual’s only listed cause for 11 is a gas shut-off valve that isn’t fully open. That’s typical after a new installation, after gas work, or after someone bumped the valve handle. On the gas pipe feeding the heater, the handle should line up with the pipe.

If the valve is already fully open and other gas appliances work, the manual’s remaining instruction for any code that won’t clear is to call for service. Code 11 is an ignition code on Rheem-built tankless heaters: Rheem’s IKONIC service guide (opens in a new tab) describes the matching A011 as no flame detected after repeated ignition attempts, so the technician will look at gas pressure, the igniter and flame sensing. The same code on Rheem-built models is covered in more depth in Rheem code 11.

Code 12: gas supply interrupted

The manual lists two owner causes for code 12: the gas service was interrupted (call your gas utility) or, on propane models, the LP tank is running low. As general background, a tankless burner draws far more gas at full fire than a stove burner, so a nearly empty propane tank can show up here first.

If gas supply is ruled out, a technician looks at flame sensing, venting and gas pressure. See Rheem tankless error code 12 for what that visit involves.

Code 29 or A029: condensate problem

Only condensing models show this code. A condensing tankless makes acidic condensate, which drains through a neutralizer or a condensate line. On Encore RMTGH models, 29 means “neutralizer is clogged.” On Encore S and SR models, manual AP22745 (opens in a new tab) defines A029 as “blocked condensate line.”

Both manuals send this code to a dealer or technician. You can help by checking that the condensate tubing running from the heater to the drain isn’t kinked, crushed or frozen, and noting whether water is backing up at the heater. Don’t open the heater or the neutralizer housing. If condensate is dripping where it shouldn’t, see water dripping from water heater exhaust.

The reset sequence Richmond gives

The RMTG and RMTGH manuals describe the same steps:

1. Turn off all hot water faucets.
2. Turn the heater off with the POWER ON/OFF button on the display or remote, wait about five minutes, turn it back on, and open a hot faucet.
3. If the code is still there, turn off the faucet and the heater, unplug the heater for about 30 seconds, and plug it back in.
4. Carry out the remedy in the chart if it’s one you can do (open the gas valve, refill propane, open the fixture further, clear the vent).
5. Restart and test again. If the code is still shown, write it down and call for service.

Encore S and SR models clear stored alarms from the display menu (SERVICE, then “Clear Alarms?”), but clearing an alarm doesn’t fix its cause.

Encore S and SR codes

Models with the text display add an A0 prefix and list more faults. Beyond A011, A012 and A029, the AP22745 manual includes A014 (overheating), A017 (leak sensor detected water, on Rev 06), A032 (heat exchanger thermistor), A055 (gas valve), A065 (water flow solenoid), A071 (gas solenoid valve), A072 (flame detected before ignition) and A090 (blocked intake or vent). For every hardware code the manual’s remedy is to contact a dealer or qualified technician. T113 means flow is too low and T111 is a flush reminder.

Frequently Asked Questions

Q: My Richmond shows 88. Is it broken? A: Not by itself. Code 88 is a maintenance reminder to flush the heat exchanger or replace the water treatment filter. The manual describes clearing it from the control panel after that maintenance is done, so clearing it without flushing only hides the reminder.

Q: Is a code 29 on my non-condensing RMTG the same thing? A: The Essential Plus RMTG chart doesn’t list 29. If one appears, follow the manual’s instruction for unlisted codes: turn the heater off and call for service with the code and model number.

Q: Where do I get help with a Richmond tankless? A: Richmond’s contact page (opens in a new tab) lists a tankless support line. Have the model and serial number from the rating label and the exact code ready.