Can you use a multitester?

Your syatem is working correctly. Because it is a 2 wire system you have to leave the thermostat in the HEAT setting. The relay box on the furnace is where you switch it to COOL. It operates by using a relay, when on HEAT at the furnace the relay looks for closed contacts at the thermostat to operat...

Get rid of the ridge vent. Pull it and cap the ridge with shingles. Then cut in some standard aluminum roof vents, approx. 4 on each side of the ridge about 18" down from the ridge peak. These type are less prone to leaking in high winds.

Ostracon I see problems with your set up, 1) Most park "plugs" are set up to handle 50-60 amps, not designed for 100 amp service. 2) You have a fuse box with 2 150amp fuses in it feeding a plug and service cable only designed to handle 50-60 amps......DANGEROUS!! To the OP: you may just ha...

You should be able to re-connect those wires from the AC contactor to Y and C (grey) in the furnace compartment. Someone may have taken those out of the system because of a problem they could not troubleshoot out. Maybe the fuse on the board was frying when the wires were connected. If that's the ca...

Use a gallon jug of window washer fluid and 50'-60' of 1/4" clear vinyl tubing. Drill 2 holes in the top cap of the washer fluid jug, 1 so the tubing will fit tight through it and the second one about an 3/16" - 1/8" in diameter as a vent hole. Cut a small angle cut on the tubing and ...

You need to test if the heating coils are getting power when the sequencer is kicking them on. If power is there then the elements are bad.

A 7680 furnace would indicate 80,000 BTUs of heating, however the coil's model number, 7842, looks like it would require a condenser rated at 3.5 tons, 42,000 BTUs of cooling. I think that would be overkill as far as air conditioning requirements. Home would be cold but get cooled to quickly and not...

That's alot of work to have something not much better than what you started with. Tear it all out and make new rafters out of solid lumber. You said it was a 12' wide home. Measure the height at the center of your current rafter. That measurement will decide if you need a 2x6, 2x8 or 2x10 lumber to ...

Transformers hum, nothing to worry about. No need to change the thermostat as long as you understand the operation of it.

What type of thermostat is on the system? Is it a heat/cool thermostat or a heat only thermostat? The 2 wire sytem requires you to use a HEAY ONLY thermostat. The relays in the box are set up to recognize closed contacts on the ts-tat when in heat mode and open contacts on the t-stat when in cool mo...

Sounds like it's working right. The relay only powers the fan if there is power there to send to the fan. When the Tstat is on cool and calling for the air to be on the blower will run regardless if the switch is in the AUTO or ON mode. When switched to OFF the blower should stop. If something short...

Freon (R-22) is still available although it has doubled in price since last cooling season. If you need freon there is a leak someplace, probably not worth tracking down though as it can run into some $$$. You can try another company, many are high pressure sales operations and will do all they can ...

That's a fresh air inlet. Sometimes they have an additional fan motor up top but most are just a vent. In really dusty/dirty environments too much dirt is pulled in unfiltered into the furnace and subsequently into the living environment. I disconnect them and use foil tape to close off the hole on ...

Is the booster motor running when you set the thermostat high enough for the heat to come on?