There isn’t much that you have to worry about with gas on your minivan camper conversion, except leaks in fittings or hoses, and the proper regulation of it, which is handled automatically if it’s working right. Normally regulators give many years of trouble-free service, but like anything mechanical, they can become faulty. We knew of a guy that actually threw out a perfectly good appliance (a wall heater) because he couldn’t keep it lit. He had tried buying a new thermocouple, and that didn’t solve the problem so he threw the appliance out and bought new one. I installed the new one and couldn’t keep it lit either… until we changed the regulator on the propane tank. That solved the problem, and then he was kicking himself because he threw out a nearly new, perfectly good wall heater that cost well over $100.
Anything that is stored in a sealed container is going to change pressure, mostly due to temperature, but even the volume of the substance inside can affect the pressure. If the substance is stored under pressure to begin with, it will still change. That is why you need proper regulation to control that pressure and keep it constant, to make it useable and safe. So you never want to try to hook up to a propane tank without one.
Regulators are designed so that when they fail, they usually fail toward low pressure, rather than suddenly letting out all the pressure in the tank. That is a good safety feature because otherwise it could turn a normal stove burner into a blow torch! We certainly wouldn’t want that in our minivan camper conversion! In most cases when a regulator stops doing it’s job, it simply shuts down or reduces the pressure coming out of it. That’s what happened with the gentleman’s wall heater.
Most regulators are fairly simple and easy to change. Some are not designed for mounting, while others are designed to be mounted to a wall or bracket and then the gas lines connect to them. Most are simple “one tank” regulators, but there is another kind, called a “changeover” regulator. Those kinds are used for setups where you have two tanks connected to it. When one tank runs empty, it automatically switches over to the second tank.
Regulators and other fittings, such as little “meters” that tell you how much propane is in the tank yet (called a tank level indicator) are readily available at most hardware stores, gas companies, and home improvement stores.