My Rheem Criterion II Furnace Is Not Lighting

Power Supply

• The Rheem Criterion II will not light and will not function if the furnace has lost power. Check the power cord and plug the cord into a live electrical outlet, then turn the furnace's main power switch to “On.” If the furnace still does not start to power up, check the household fuse or circuit breaker and reset or replace the fuse or circuit breaker as needed.

Gas Supply

• Another potential reason why the Criterion furnace will not light is if the furnace is not getting enough gas. The gas supply valve is usually found behind or next to the furnace and should be turned fully counterclockwise to the “Open” or “On” position. Note that if you smell gas when you are checking the furnace, turn the furnace off immediately and leave the house quickly. Call your gas company or fire station for help.

Relighting the Furnace

• Sometimes the furnace needs to be relit, though the system uses an automatic electric ignition system. This is usually due to power failure or a lapse in the gas supply. Again, smell carefully for gas before proceeding and leave the house if you detect any gas. If there is no smell of gas, turn off the furnace and set the thermostat to the coldest setting. Find the gas control valve behind the control door and move the valve to “Off” before waiting five minutes to let any gas clear out of the system. Smell one more time for gas before moving forward by turning the valve to “On” and shutting the control door. Turn the Criterion power switch to “On” and turn the thermostat back up to a warm temperature.

System Lockout

• If the Criterion furnace tries to light two times unsuccessfully, the furnace will automatically lock out for one hour. During this time, check the vents in the house and clear away items that may block or obstruct the vent and clear the entire area around the furnace. Clean the filter or replace the filter if necessary and look for other potential sources of blocked air flow to the unit. After one hour, disconnect power by turning off the furnace power switch and waiting 10 seconds. Then turn the furnace back on and allow the system to ignite. If the furnace still cannot light, turn the power back off and call Rheem for assistance.