Tankless Hot Water Heater Rtg-74pvp-2 7.4 Gpm: Unit isn't turning on when I turn on the hot water...

http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

Contact service technician
Call Rheem

Gene

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

Bad circuit board?
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

If it's older than 5 years, then replace with tank-type heater
http://waterheatertimer.org/How-to-install-gas-water-heater.html

Gene
h

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

http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
Bad circuit board
If unit is older than 5 years, replace tankless with tank-type
http://waterheatertimer.org/How-to-install-gas-water-heater.html

Gene
h

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 link for Rheem tankless troubleshooting resources including error codes and typical maintenance:
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 link for Rheem troubleshooting resources.
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

No error code can mean variety of problems:
http://waterheatertimer.org/pdf/No-Error-Code.pdf
http://waterheatertimer.org/Low-hot-water-pressure.html
http://waterheatertimer.org/Crossover.html

If thermostat is set high that can also cause unit not to turn on.

Rheem tankless do-it-yourself troubleshoot resources
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html

This is something you will have to contact rheem about due to the fact you don't have a fault code

Sounds like you may have the wrong type gas going to this? Is this an LP gas or natural gas unit? will say on label. Natural gas units run only on natural gas ditto for LP. Could be issue with manifold pressure settings. Could be obstruction in exchanger or vent. Have a authorized technician check over

my rheem pronto tankless water heater will not turn on?

in order to reset the unit you will have to turn the temp all the way down then unplug the unit for 5 min,, remember it is a computer and it knows, after plugging in back in after the five min, reset the temp open up a fauset while doing this, that way it will be regestering the flow of water to set the temp by