saturdays inspection

Mountain vacation home had a new water heater installed. Handyman installed Natural Gas heater on a propane system. When turned from pilot to medium high, CO measured 999 PPM ( highest it will register ) at the draft hood. Turned down to low and opened windows. After five minutes CO leveled off at 550 PPM.
There is no way the new owner would have caught this. In addition, the combustion air vents were stuffed with insulation. No one had been in the home since the heater was installed. Heater was three feet from washer and across the hall from basement bedroom. I always place a CO detector on top of the water heater while inspecting it. This is what we get paid for.

propane burns at a much higher BTU content than natural gas. I’m surprised the heater worked at all, unless someone changed the regulator.

Good catch. I live in an area of San Diego where everyone has LP. But most of San Diego has natural gas. We often see NG appliances installed without being converted.
A weird situation was that I once missed an LP water heater installed on NG which is very unusual since LP water heaters are not readily available here. You have to go out of your way to get one.