Richmond Tankless Water Heater Ignition Problem?

by Bob C
(New Lenox, IL)

The Richmond RMTG-74PV unit has been working fine since installation(July 2009) until a few months ago. It still functions, however if its been running for any period of time and the hot water is turned off, it fails to re-ignite unless we leave it alone for several minutes.

The error codes are flashing C2 and/or C11. I don't believe the problem is poor plumbing/water intake or gas pressure (its been fine for almost 2 years and nothing has changed). I've cleaned the air intake and cold water filters every couple months. I took the cover off to look around and the only visible fuse appears to be fine.

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Apr 05, 2021
flame sensor issues
by: DaveC

It is most likely the flame sensors. I have to clean mine once a year without fail. Minor carbon built-up causes them to not sense the flame. Use a little emery cloth to polish them up and they are good to go again. I have another brand water heater at the cabin and it has the same issue....must inherent with the tankless heaters.

Mar 14, 2017
Richmond Tankless Water Heater Ignitor Problem
by: Tim S

Is there a recall or a service bulletin being issued for these? It sounds like the dirty ignitor is the main problem. The system is not set up to run with any type of common flexuations in Gas Pressure and or minor carbon buildups. Units should be designed better to run longer without issues.

Jun 29, 2016
cleaning flame sensor no
by: Randy

Steve what had to be removed I can feel the sensor but can't see it

Apr 10, 2016
Clean flame sensor for proper operation
by: Steve

I have the same problem it worked out that it does not have enough space to operate in so I have to clean the flame sensor about every three months it's a pain but I can do it my self

Apr 03, 2011
C11 and C2 error codes for Richmond tankless water heater
by: Jeff

Your Richmond tankless water heater is pretty the same as Rheem tankless water heater which is owned by Japanese Paloma Industries. Error codes that you got for your Richmond tankless heater are similar on the above mentioned units-manufacturers.

Error code 11 basically shows the problem with the ignition - no ignition. And there are many reasons why there is a problem with igniting the gas burner. You said you have checked the gas pressure, but I would ask the gas company to see is there any difference in the pressure when they deliver the gas.

If for any reason your gas piping is undersized that will mean that whenever other gas appliance is working (you didn't mentioned is there any) there will be a pressure drop and the flame will wave, cause the irregular operation and the error code will kick in.

Someone should check is there too much air in the gas line and bleed all the air. Lack of quality gas will I think affect the proper gas ignition.

Did anybody checked the solenoid gas valve? Gas valve on your Richmond tankless water heater might have the open or short circuits.

Another thing that come to my mind is related to the ignitor. Ignitor should be operational, it has to initiate the ignition; wiring harness should not be damaged. The proper Amps should be found... and I am suggest that all the service should be done by the qualified technician.

Hope this helps.

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