Error code tankless gas

Copy following link for Rheem tankless troubleshoot resources, including error codes, manuals, and general information for maintaining your tankless computer that heats water.
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
Multiple error codes can indicate failed PC board. Rheem will send PC board... so your computer-that-heats-water might have failed motherboard.
Continual maintenance can help avoid common error codes, but some problems are insoluble and chronic.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

1) Copy following links for Rheem tankless error codes
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
http://waterheatertimer.org/pdf/Tankless-Error-code-13.pdf

2) Maintain water heater as shown in product manual to avoid common error codes.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Code 14.
What water heater do you have?
Question posted under tankless Bosch, but these error codes start with a letter.
Rheem/Richmond etc Tankless has error code 14
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
http://waterheatertimer.org/pdf/Paloma-Tankless-Error-Codes.pdf
Call tankless service technician.
Ask technician how much it costs to have recommended yearly service.

Or install whole new tank-type gas water heater yourself for $350 from local box store, and avoid the entire headache, then sell tankless online for parts.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Try a new sensor . I cannot see who told you to wipe the pipe it will do nothing .

Before calling service technician, open following link for troubleshoot resources include Rheem chat, error codes, and regular maintenance manual, and possible product manual:
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
http://waterheatertimer.org/pdf/Tankless-maintenance.pdf

Clean the water filter as shown in product manual.
Error E1 is not specifically shown for Rheem/Pronto tankless.
1 is usually related to water flow.
E errors are related to temperature, so E1 can be temperature sensor failure on hot water pipe.
E errors can be loose/bad wiring or part failure.

Error codes are considered start-point for troubleshoot.
Each tankless manual recommends cleaning the water filter monthly, deliming heat exchanger yearly, and cleaning combustion chamber and burner parts yearly.
Regular maintenance can prevent most common error codes, but the cost and nuisance will outweigh expected $1-8 monthly savings on gas bill.
The requirement for continual maintenance should signal folks that tankless are not effortless hot water as described in tankless promotion.

Solve most tankless problems same day, yourself, any brand, using minimal tools for about $350.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

It is safe.
Before calling service technician, open following links for troubleshoot resources, including possible manual, error codes, Rheem chat, and routine maintenance.
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
http://waterheatertimer.org/pdf/Rheem-error-code-C7-76.pdf
http://waterheatertimer.org/pdf/Tankless-maintenance.pdf

e2 is not shown among common error codes:
Error e2 might be: Brownout condition or too low of voltage to thermostat. Double check wiring and check for 24 vac between R and C. E2 will clear 15 sec after proper voltage is restored.

Before calling service technician, open following link for Rheem troubleshoot resources including Rheem chat and typical generic manuals and common error codes:
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

Model number and serial number are required for Rheem contact, and then they tell you what error code means without saying how to fix it, and then tell you to call service technician.

Tankless water heater manuals each say to have qualified technician perform yearly service. Most causes for common error codes are covered by yearly service.

Yearly service is fairly standard in the HVAC and water heater industry with advancement of high-tech 'energy' saving appliances. Of course all costs are energy, and the service call probably costs more that the 'energy' saved by energy-saving appliance. But with high tech stuff like tankless, it is good to have a reliable service guy who knows your machine.
http://waterheatertimer.org/images/Tankless-wiring-1200.jpg

Before calling service technician, open following link for Bosch troubleshooting resources, including error codes, manual, Bosch contact info, and service bulletins.
http://waterheatertimer.org/Troubleshoot-Bosch-Tankless-water-heater.html

Error codes are starting point for troubleshoot.
e2 is cold water temperature sensor fault.
Bosch error code says: 1) Check connector on wires coming from top of water valve for a secure connection.
2) Sensor may trip if water temperature drops below freezing to protect heater from freezing conditions Any damage due to freezing conditions is not covered under warranty.

Another contributing cause can be temperature thermostat set very high and tankless sensor is going bad, and very cold incoming water, or combination of factors above.

Also read manual for advisories and required maintenance. Some units require water filter be cleaned monthly.

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on water heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

You posted under Rheem water heater
E2 sounds like a Bosch error code: E2: Cold water temperature sensor fault.
http://www.boschhotwater.com/HelpfulResources/TechnicalSupport/BoschAquaStarModels/2400ESTechSupport/Troubleshooting/tabid/1295/Default.aspx

it sounds like your flu pipe may be clogged,, they just snap together or have little screws holding them together,, take the sections apart and make sure nothing is is the line reinstall and try it out