I was called to a home to inspect a heating issue. Upon arrival, I found that the heating system was not working. I checked the thermostat and found that it was not working. I checked the power supply and found that it was working. I checked the gas valve and found that it was not working. I checked the gas orifice and found that it was clogged with spyder web. I cleared the spyder web from the gas orifice and tested the heating system. The heating system worked, but there were other issues found.