In Reply to: Re: MIght be time for a new furnace posted by Farmer Dan on October 16, 2017 at 13:56:39:
I understand how you need a new furnace. But do not expect miracles from it.
I would advise you to look over the controls and understand what they do.
They follow Murphys rule and STB on a Saturday evening at 10pm.
Our newer furnaces here can be a real PIA.
First after the thermostat calls for heat.
It starts the exhaust fan. You can not buy just the motor. It comes as a package only with the fan attached. (about $200 on amazon .com) On one of our furnaces the wire
the motor to he electric circuit broke. A wire as fine as a piece of hair. I was able to resolder it to the plug and got it working.
When a sensor picks up a negative pressure in the fire chamber, It starts a heater
element glowing. When another sensor sees the heater is hot enough, it turns on the
gas. There is also a sensor outside of the fire chamber that watches to see if a
flame escapes from the fire chamber. If it detects anything it shuts down the whole
system. A sensor above the heat chamber controls the fan blowing the warm air to the house. There is also a over temp sensor to shut the system down up there.
When I was laid up medically, the heater element burned out and the furnace would not come on.
Head Honcho had a repair man come in ( I worked for the man that started that
business in 1955. He would not have ripped people off like the young guy that has the business now) He charged $80 for the house call. I was ok with that. But he charged $135 for the part I cold get local or off amazon for $30
I hope this will help you understand how these new furnaces work.