I just had my furnace cleaned it is a gas rheem. The service guy said it was overheated because of a#3 tube he said the furnace heat exchange is black. What can be do regarding this
Water Heaters - Rheem - 50 Gallon FVR NATGAS Water Heater 6YR 22V50F1
I presume you're talking about a gas furnace, even tho the title says Rheem gas water heater. Either way, it works the same for both.
Any black coloring on the heat exchanger is *not* from overheating. Black is from a sooty flame caused by a mis-adjusted burner. (In fact, a sooty flame is less hot). There is an adjustable "air intake plate" for air to enter the burner where the gas enters the burner. A proper flame is made by adjusting this air opening so the proper gas/air mixture feeds into the burner. If the air vent is closed too much it produces a sooty flame. The age of the furnace is the most important aspect, and that helpful to determine a likely condition of the heat exchanger and burners. Other than a badly adjusted flame, the main thing to watch for is a badly rusted out heat exchanger. But black does not mean rust.
Answers & Comments
I presume you're talking about a gas furnace, even tho the title says Rheem gas water heater. Either way, it works the same for both.
Any black coloring on the heat exchanger is *not* from overheating. Black is from a sooty flame caused by a mis-adjusted burner. (In fact, a sooty flame is less hot). There is an adjustable "air intake plate" for air to enter the burner where the gas enters the burner. A proper flame is made by adjusting this air opening so the proper gas/air mixture feeds into the burner. If the air vent is closed too much it produces a sooty flame.
The age of the furnace is the most important aspect, and that helpful to determine a likely condition of the heat exchanger and burners. Other than a badly adjusted flame, the main thing to watch for is a badly rusted out heat exchanger. But black does not mean rust.