Water Heater not heating- system lockout message constant

Make sure all gas is turned on to the heater, ignition lockout can be one of several things, the majority of the time its a control board but, it could also be water in the heat exchanger pot, which would keep the ignitor from working, or a bad igniter.

There is either a problem with the ignitor or the flame sensor.

sounds like a bad thermacouple. thats the "sensor* that the pilot flame hits

I know that depending on what part of the country you live in, some areas can have there utility equipment out side the home not sure of your at but the exhaust must have a certain distance from the unit. If you exhaust threw a wall you should be fine. That being said I would check the inlet to make sure that you have good water flow there should be a small filter at the inlet for the cold water. You check and clean this anyway because you water was off. Then bleed the air out of the system. There are other things to check, but start there.

Open following link for troubleshoot error codes showing 7 flashes on Honeywell gas control valve is system lockout due to flammable vapor:
http://waterheatertimer.org/pdf/Honeywell-gas-control_error-Damper-series.pdf
The FV system in Rheem can be tripped by presence of flammable vapors such as gasoline or paint fumes etc, or it can be tripped if water heater was dropped, or mis-manufactured, or if gas control valve is defective, or if water heater is not getting adequate fresh air, or there is inadequate venting of combustion by-product.
When combustion chamber overheats, then glass vial breaks and damper shuts off air supply to water heater and it will not light.
Open following link for possible help fixing the problem:
http://waterheatertimer.org/How-to-repair-Rheem-FVIR.html

usal problem escpecialy on the farthes spout because it has to heat up the water from the heater to that tap with a tankles u can put a seprate circulating system which requeris another smaller tankles unit or elctric unit to heat and ciculating pump and run a line all the way to ur farthes tap which keeps constant hot water to everything but all of this is farily expensive alot of times most people usaly deal with it if u look more into it email me and i can give u a detaled instructions.

If any of the water, to the heater, from the heater or in the heater gets below 32 degrees F. for any length of time, there is the potential of freezing and breaking piping.
Now if the water is constantly being heated and used, as long as the cold inlet supply does not have the opportunity to freeze, the system is less apt to freeze, but in my opinion, this system should never see 32 degrees with water in it.
Gary

Flame sensor would be my first diagnosis. Take it out and clean it with some emery cloth or some light grit sand paper and put it back in should be fine just needs to be cleaned.

You are actually getting a 90 error code. This error code occurs if the unit is dirty and overheating. I'd recommend contacting a servicer to clean your heater with compressed air. They'll need to remove the fan motor and manifold plate to fully clean the burner chamber and heat exchanger.

Got the same problem here! Did you find a solution?