Low pressure in propane bottle.

[B.G. Smith]

Have a cylinder I have been trying to use up in the trailer for some time. Hot water heater won't stay lit on it. I removed it and it appears to still have maybe a gallon of liquid in it, hooked up a gage this morning and it only read 40#, temp outside was in the 60s. I' gonna completely empty it and refill, just wondered if anyone had run into this.? bg

 

[RikDavis]

Assuming an RV system possibly a regulator problem. The gas appliances require 11 inches of water column which, as near as I can remember is in the neighborhood of 7 ounces so 40 lb pressure from the tank wold be fine.
Does the appliance run properly on a full bottle? How does the flame look on your stove or fridge?

 

[TLane]

At 60 degrees, the vapor pressure of propane is around 100 psi. Were you using gas from the bottle just prior to measuring the pressure? As you use gas, the liquid in the bottom of the bottle evaporates, which refrigerates (cools) the liquid. This will cause the pressure to drop, but usually you shouldn't have any problems with pressure unless you're using a LOT of propane or it's quite cold outside. How long have you had the bottle, and where are you getting it filled? Is it possible it has something else in it?

 

[B.G. Smith]

Assuming an RV system possibly a regulator problem. The gas appliances require 11 inches of water column which, as near as I can remember is in the neighborhood of 7 ounces so 40 lb pressure from the tank wold be fine.
Does the appliance run properly on a full bottle? How does the flame look on your stove or fridge?

I can switch to the otjher bottle and the hot water heater will run. Refrig runs fine. Flame at stove loks ok but somtimes the flame will seperatew from the burner is a few places. bg

 

[B.G. Smith]

At 60 degrees, the vapor pressure of propane is around 100 psi. Were you using gas from the bottle just prior to measuring the pressure? As you use gas, the liquid in the bottom of the bottle evaporates, which refrigerates (cools) the liquid. This will cause the pressure to drop, but usually you shouldn't have any problems with pressure unless you're using a LOT of propane or it's quite cold outside. How long have you had the bottle, and where are you getting it filled? Is it possible it has something else in it?

Bottle is old but was upgraded about 4 years ago with the new valve. UI usually refill at Flying J as they have the best price in this area. Something else in the bottle? That was my thought. Just wondered what it might be. I bled the rest of the bottle off today, couldn't smell any mercaptan until it was empty. Bottle has probably been used a couple of years since refill. bg

 

[DennyDay]

Sounds like you could have some water in the bottle - - H20 weighs 8 lbs. per gallon and LP weighs 4 lbs. per gallon so it wouldn't take much to make you think you had LP going by weight - - could be caused by condensation if the bottle hasn't been used for four years. Suggest you drain bottle and see what is in it - - If you are not comfortable doing that get an LP dealer to do it for you. Even if you only had a 1/2 gallon of LP liquid, the pressure before the regulator would be over 100 at 60F.

 

[Wingate]

does your other bottle work ok when connected to that hose?

 

[B.G. Smith]

hecked it since I changed the bottle, it is about 53 miles away but I will check it soon. bg

 

[MLee]

The safety valve inside may have gotten stuck or maybe when opening the valve to quickly caused it try and shut down the tank from exhausting to quickly. This some times will happen and the pressure has to be bleed off and then the knob turned back on very slowly, just cracked and then slowly opened.

 

[B.G. Smith]

I have had that happen, I can actually hear the valve click shut if I open too fast. Good point though, I have thought maybe the excess flow valve is not reopening completely. bg