Propane Furnace Question
 

I noticed a propane odor in the garage, where the furnace is, and checked the thermostat. It was off, for some reason. The propane tank is nearly full. I turned the thermostat on, and the furnace fired up. (It's cool and foggy here on the Norcal Coast.) After a while, the propane odor was gone.

Why was there a propane odor? Is this normal?

I'm not familiar with propane furnaces but assume they are like natural gas, except for the fuel. That being the case, there should be no odor of gas at all.

If your furnace has a pilot light, that could account for the smell if the pilot had blown out but you said the furnace fired up as soon as you turned on the thermostat so that is out as a cause. If the furnace has an electronic ignition, then there is no gas flow until the thermostat signals a need to light the burner.

Regardless, if you smell gas you have a problem--maybe a loose connection, pin-hole in a connecting line, or a partially opened valve. Get it remedied immediately by calling out the gas company. They will come out and use their "sniffer" to find any leaking gas.

BTW, is your water heater also located in the garage? If so, the same cautions apply and that may be the source of the smell.

you might want to get a carbon monoxide (CO) detector.

last week, a plumber was in my basement, soldering some water pipe. about a half hour after he left, the CO detector started buzzing and kept buzzing until i opened all the windows to air out the basement. it must have been the leftover vapours from his propane torch. i was pretty impressed with the detector, made by garrison.