Dumb Newbee Questions

[jmlocklin]

Okay here goes. I have a trip planned and with the weather getting colder I am sure I will need to use the heat. I have two 30 lb propane tanks. Only one is in use but there is no gage that I can see to tell how much propane is in the tank. Here is the dumb question, How do I know when the tank is empty or about to be empty? the other question is about how long should the propane last. Any help will be appreciated before I learn the hard way.

[busterbrown]

Your coach's LP delivery system is fitted with an auto change-over regulator. When both tanks are full and both tank valve's are open, the regulator will pull LPG from the tank that the selector arrow is pointing at (tank 1). Most regulators have a window that indicates "green" for "gas" and "red" for "no gas". When tank 1 becomes empty, the regulator will automatically switch over to the other tank (tank 2) and gas will continue to flow. The selector will continue to point to tank 1 but the window will be "red" now.

At that point, an owner has two choices. First, they can continue using their LPG appliances until the 2nd tank depletes. This may result in a late night "gas emergency" when the 2nd tank becomes empty. Since fuel retailers aren't usually open in the wee hours of the morning, most owners choose the alternative method. The preferred option has the owner flipping the selector valve to tank 2 after tank 1 becomes empty. Tank 2 will continue as the primary reservoir and the window will indicate "green" status. Now, tank 1 can be safely turned off, removed from the system, and refilled. LPG will continue to be drawn from tank 2. The window will continue to indicate "green status" until tank 2 becomes empty, and the process repeats itself. Continuing like this will prevent an unwelcomed cold coach, cold shower, or cold meal.

There are multiple ways to determine fuel levels in an LPG tank. The first and most conventional method is by simply weighing an empty tank. A 20 lb tank usually has a tare (unfilled) weight of 17 pounds when empty; 30 lbs is roughly 25 lbs. At 4.125 lbs per gallon, a 20 lb and 30 lb tank will receive 5 and 7.5 gallons respectively. Do the math and you can see how much a full tank will weigh.

Alternatively, water poured down the side of LPG tank can indicate where the level of liquid propane is by feeling for a temperature gradient. Propane will absorb the heat and you'll be able to estimate the point at which liquid propane begins. This is fairly reliable.

A relatively newer bluetooth method has won me over. It's a tank monitor device sold by AP Products (http://a.co/2Z9ajd2) that measures fuel level from below the tank. The magnetic sensor attaches to the bottom of the tank and relays tank and sensor information to an downloadable app or a display monitor. I've been using it for over a year and it has been very convenient and accurate.

There are other "gas checker" instruments such as this (http://a.co/6m2xADs) one by Dometic which uses ultrasounds to determine levels. I didn't have good success with this one prior to buying the AP Products kit.

Other gimmicky LPG pressure gauges hooked directly to the tank are not worth buying as pressures remain constant inside the tank until almost empty. The gauge will read full and abruptly fall to empty when LPG is just about out, giving you very little warning.

As far as how long your tanks will last in cold weather depends on many variables including the size of your coach, your personal comfort levels, the insulation factor of your coach, the outside temperature, wind, etc. I have two 20 lbs tanks on my coach and used up almost both tanks on a 4 day deer camp trip last year as temps hovered around 27 degrees at night with a piercing wind against the trailer. The furnace ran quite frequently. In comparison, we used our coach the entire summer (May to September) at state parks with a long distant trip to Florida (propane fuel to cool the fridge). The tanks were never refilled once. Any furnace will be the gas hog.

[mazboy]

2 30 pounders? just use one and keep the other off. you'll know then when you need to refill.
the down side is when you run out during the night and the furnace isn't working, but you just run outside and turn the other tank on.

keep it simple.

as for how long propane lasts? who knows.

[jmlocklin]

Thanks for the information and suggestions.