The R40 has an on board computer with a photocell that views the flame color. If the photocell does not like the color of the flame, then the heater shuts down....within 5 secs. Your problem could be:
the air pump pressure incorrect..
defective electronics.
restricted fuel supply.
air leak in air line or fuel line
You must troubleshoot each of the above- starting with setting the pump pressure.
My 4 year old Rheem 10 gallon electric water heater (model 61-SVP-10-S) does not produce hot water....
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My 4 year old Rheem 10 gallon electric water heater (model 61-SVP-10-S) does not produce hot water. I tried changing the heating element but to no use. There is power from the thermostat to the heating element. What option do I have to get hot water.