No Heat

[ThreePutt]

I need some help with the furnace. When I turn on the furnace there is nothing, no noise, no hum no sound at all. The AC works great, I have the Duo-therm thermostat by Dometic. I called Suburban and they blamed Dometic and I called Dometic and they blamed Suburban. They were no help at all they just kept saying to call a tech. I hate to call a tech if it is something simple to do. The fuse is ok at the converted. Thank you

[Hunter11]

Larry you are killing me. Here you are talking about your heater and today was our 62nd day over 100* this Summer.

[Chrisnan23]

OK, so even with the heat< the way it works is this,
1) Thermostat closes calling for heat.
1) the fan on the furnace starts to purge the fire box of gas.
3) the valve is opened by the board.
4) the ignitor sparks to light the gas.

All this is done on 12volts dc, even the fan., so the first thing to do is get to the wiring for the furnace and find the following, the large wires are +12v (usually red from the furnace) and common (usually Yellow) These are for the fan after going throught the control board. The two blue wires are the thermostat input the one marked with a + is the 12 volts in when the thermostat call for heat. Check for the voltage at the furnace first if it is there then it is a furnace problem.

[ClassicHammond]

Do you hear the furnace trying to light.....should click 3 times. Also I usually turn on the stove till I smell gas making sure the air is out of the line.

[ThreePutt]

Hunter, I feel your pain,but it was music to my ears, when the furnace turned on. I think the brushes were stuck, when I gave the fan a spin, the furnace turned on. This past spring the shaft on the AC was stuck and when I gave that a spin, the AC kicked on, I oiled the shaft and have had no problems since. I just thought I would pass this along in case anybody might run into the same problem. Chris thank you for your help. If I hadn't tried what you suggested, I would not have tried spinning the fan. Sorry for the long post.