Rheem #3204-1000d gas furnace

[rafael]

Well....whining about my furnace in the war-stories section got me to thinking [and that is a dangerous thing] about fixin' my old furnace.

The symptom: Fires right up, then the little Honeywell overtemp thingie cuts of the burners within about one minute, leaving the fan to destribute luke-warm air. It does this over and over, and that's OK during the Autumn and Spring, but a couple of colder days each winter means the furnace can't keep up.

Absolutely a cracked exchanger or is there anything else I can do before replacing unit?

Thanks!

[Guest ahammer48]

Hello

Yes. Replace the little Honeywell limit thermostat and C if problem goes away.

Simple checks to C if the exchanger is cracked: if you have a standing pilot flame(always on) start the blower and watch the flame 2 C if its getting blow around or blown out.

If U have cycling pilot (only lights on a call 4 heat) start the furance and watch the main flame 4 the above signs. Does it look like the flame is being pushed out of the furnace when the blower starts??

Naturally the best way to check for a cracked exchanger is with a CO2 tester.

Hope this helps.