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DEAD, just died 1993 Tempstar nat gas furnace HELP

PostPosted: Thu Dec 29, 2011 3:43 pm
by eclipse
Hello, I have a Tempstar, direct vent * & * 90% from - mod NUGS100BH04. On Nov 27th, I replaced the fan control box. It worked perfectly until yesterday morning * 27th, *. It kicked on for an hour, for the morning warm up, then it shut down before achieving the morning temp.

Since then I - replaced the thermostat, switched it to a different breaker, have over-road the safety switch on the side * bi-passed *, have tested the two leads on the fan door switch-power is there. I am mechanically inclined, could wire your house from the ground up, but not good w fine electronics. I have also tested the new thermostat w the fan in "auto" or "on" modes, NOTHING, the fan will not kick on? The furnace; is completely quiet, the fan for the combustion system does not come on either, again NOTHING.

Yes, the new thermostat is set for heat at 70 degrees & my house temp is now 50 degrees. Usually, when standing by the furnace, when I flip the side safety switch to on, the furnace clicks internally. But now, NOTHING, it is entirely DEAD - NOTHING. Please I need some help !

- DEAD, just died 1993 Tempstar nat gas furnace HELP

PostPosted: Thu Dec 29, 2011 11:16 pm
by Freon
Since it appears you have 120 volts at the furnace, remove the R and C wires from the furnace control board and label them. Now test for 25 volts, AC between the R and C terminal at the furnace. If no voltage, look for a blown fuse on the circuit board.

- DEAD, just died 1993 Tempstar nat gas furnace HELP

PostPosted: Fri Dec 30, 2011 9:31 am
by heatseeker
Sounds as if you have just enough knowledge to be dangerous. Residential Electricians don't make good ac techs but that is just my not so
humble opinion.

- DEAD, just died 1993 Tempstar nat gas furnace HELP

PostPosted: Fri Dec 30, 2011 1:53 pm
by how
I am not reading anything that says your thermostat is actually working at all. The first and easiest check to eliminate the thermostat (OR THERMOSTAT WIRES) as the culprit is to jumper (R & W) on the board to see if the furnace fires up.