My furnace is not working properly. I shut down the whole electricity and also the switch on my furnice and waiting a few minutes to turn all back on. It will heat up the house and turns off automatically when it reaches my desired temperature setting. But when it needs to start back again it will lite up the fire and turn off about 3 times but never turn on. I have to keep resetting to get the heater to turn in. Changed the filter already and I did see a small light turn off and blink 7 times consecutively.
A red light flashing 7 times typically means the furnace is in lockout mode, which based on your description seems to be your situation.
There are many things that could cause the furnace to fail to light, each of which requires its own diagnostics to determine if it is the problem.
Since it sounds like you don't know much about furnaces, your best bet would be to contact a local licensed HVAC company.
Things that could cause a furnace to fail to ignite include, but are not limited to...
- Gas off.
- Electricity off.
- Clogged burner orifice.
- Bad flame sensor.
- Bad pilot assembly.
- Bad igniter.
- Bad control board.
- Bad gas valve.
- Restricted combustion air supply.
My modulating condensing boiler did that for a while. It turned out to be the flame sensor which is nothing more that a bent rod that comes close to but not touching the burner tube. It was only 3/16 inch from the tube but I adjusted it to be 1/8 inch away and has been functioning perfectly for three years. Check your service manual or google your manufacturer/model and download or purchase one.