I have a Rheem EcoSense (gas) tankless hot water heater. It is shutting off a good bit, why is that and what can I do to stop it?

Feb 2013
1) Rheem/EcoSense tankless product manual does not have specifications for length. Error 11 will let you know if venting is improper.
Often, tankless are installed outside because unobstructed venting is key for combustion of the amount of gas coming out of 3/4" gas line.
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

2) Copy following link for Bradford White venting: Exactly same as Rheem, but more installation detail. No maximum lengths given.
For lengths greater than 5 feet, a condensate trap must be installed. Acidic water from hydrocarbon combustion will damage metal, and destroy heat exchanger inside tankless if water drips back into unit.
http://hometips.me/Tls/Venting-Bradford-White-tankless-gas.pdf

3) Copy following link for tank-type power vent tables:
Generally, the longer distance requires larger vent diameter, and there is max number of elbows and/or air-flow restrictions.
http://hometips.me/Mar/Bradford-White-Power-Vent%20-tables.pdf

4) Otherwise call Rheem/EcoSense, and add comment saying what resources they offer.

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

Before calling service technician, copy following link for ecosense tankless troubleshooting resources.
C7 is communication failure with remote, and C12 is flame failure.
Multiple error codes could mean bad circuit board, loose wire, low gas pressure, or simple communication problem with remote control.
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

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

Before calling service technician, open following links for troubleshooting resources and typical manuals.
http://waterheatertimer.org/pdf/Rheem-error-code-C7-76.pdf
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

Tankless water heaters require yearly maintenance.
Many causes for common error codes are covered in the yearly maintenance.

Before calling service technician, open following links for troubleshooting resources:
http://waterheatertimer.org/pdf/Rheem-error-code-C7-76.pdf
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

Water in hose coming from gas valve caused unit to shut down how do I get water out

1/2 inch if you are using steel pipe (which is the most hearty for outdoor installations).

Happy installation:)

if your on a private well, it sounds as though your loosing enough water pressure to shut the heater off,.(which is right before the water pump comes on),....tankless heaters turn on by sensing water flow, and of course off when flo stops,......water pressure tanks often need to be re-charged with air for pressure to stay even,....does your water pressure fluctuate?

It has electric ignition. No pilot to light.

Have you try to reset the power to the heater?Then turn the hot water facuet on to see if it will start up.