This is a result of dust and other debris that has accumulated on the coils or in the heater. When you turn it on, it begins to burn off and that is what you smell.
Yes or they will overheat.
There should be a dial on the front of the heater that you set the temp. with.
It depends on your car, but should be very obvious.
Yes, it is recommended to turn off the water heater when the water is turned off to prevent damage to the heater and save energy.
coolant level could be low not letting it circulate through the heater core, causing it to blow cold. Also, if the coolant level is low it will in turn overheat.
Yes, it is recommended to turn off the gas water heater when the water is turned off to prevent damage to the heater and ensure safety.
To properly turn off a gas water heater, locate the gas control valve on the unit and turn it to the "off" position. Additionally, you should also turn off the water supply to the heater. It is important to follow the manufacturer's instructions and safety guidelines when doing this.
Turn on your vehicle's heater
Personally I do not know about a G20 1990 Chevy Van but the basics of heating are, the thermostat, heater control valve, heater fan and heater matrix. Does the van overheat at all, engine wise? Could be possible the system just needs a flush out. When you turn the heating dial (presuming it is a dial) you should hear a clunk which normally indicates the heater control valve switching over. Other than that, I've said all I can. Hope to be of some help, hope you get it sorted out.
yes because 360s do not have an internal fan and your 360 can overheat. they do make 360 fans so then it will prevent your 360 from overheating
You should check and adjust the heating temperature, then turn on the cold water to fill the tank.