Suburban WHs do not have air shutters to adjust air/fuel mixture
They rely on meter fuel flow thru MAIN Orifice
Remove the burner tube.......then remove the MAIN Orifice from gas valve body (where burner tube attaches)
Soak it in alcohol then blow it our (just blow on it with mouth......if you use air compressor very low pressure. Do NOT stick anything thru hole, you will damage it)
Reassemble and then fire off WH
Let it RUN UNTIL IT SHUTS OFF---end of heating cycle
Water temp S/B 130*F
OR IF normal t-stat dose not shut down operation the HI temp t-stat will at 170*F
From cold water to normal shut down is roughly 10 gallons per hour rating...colder water longer time
