Low Propane Flow / Pressure

[tacchino]

Have been using propane with the tank selector pointed to the passenger side and only the passenger side tank open. We were using our firepit and noticed the flames lowering and it started whistling. Figuring that the passenger tank was low I opened the drivers side tank and moved the selector to point drivers side. The whistle stopped but still have very low flames at the firepit even after setting it to full when before we ran at half or lower.

Verified that the drivers side tank has gas by checking the weight. Tried with both thanks open, tried moving the selector back to passenger side also tried opening and closing the passenger side tank. The only thing I haven't tried yet is swapping the tank locations.

New rig, new tanks and the first fill and use of both. The indicator on the regulator is full red no matter which way the selector is pointing.

Any ideas?

[Greg A]

Sounds like flow is not sufficient from the regulator. Need to hook up a manometer to adjust if needed.
Sometimes, can just be a defective regulator. Ours was straight from the factory, and they sent us one under warranty.

[Iowa Dave]

If I encountered problem here’s what I would do in order.
Turn off all gas appliances
Close both propane valves
Unscrew the tank hoses with the hand knobs.
Put hoses back on.
Turn selector to the full tank
Very slowly, very slowly, very slowly open the valve on the full tank.
Go inside the camper and open one valve on the stove burner and attempt to ignite .
If it ignites and you get a good flame that is good.
You probably had an air lock on the OPD in the full tank.
If you get a weak flame you have low gas pressure or the OPD is stuck closed. Also possible is that Your regulator isn’t open enough (low setting on the regulator ). You can take the little black cap off the front of the regulator and inset a regular screwdriver into the hole and align with the slotted screw in there.
Turn the screw counter-clockwise 1/2 turn.
Check the flame height now. If better go with it and see how your other devices work. If satisfactory keep using it that way till you can check pressures with a manometer. 1/2 turn will not be too much.
When you check the pressure with the manometer it should be 11.0 inches. But this may not be enough to supply multiple draws at one time on the system so many people are running about 11.8 inches. This will allow adequate pressure and gas flow on multiple appliances.
This has worked for me in the past
Others may have different experiences or advice.
If you need a new regulator get a Marshall.
Good Luck
Iowa Dave

[tacchino]

Thanks guys. I did go ahead and switch tank positions and confirmed good flow with the full tank on the passenger side. Will go with that for the moment and see if I can lay my hands on a manometer

[John in Santa Cruz]

i've had propane tanks get their overflow float thing inside stuck. taking the tank off the trailer and giving it a good bonk on the ground usually fixes that.

[Brian B-P]

Originally Posted by tacchino

The indicator on the regulator is full red no matter which way the selector is pointing.

Any ideas?

That means that sufficient pressure was not being delivered from either tank.

Originally Posted by Greg A

Sounds like flow is not sufficient from the regulator.

The changeover mechanism is before the regulator portion of the combined "auto-changeover regulator" in the flow path. It responds to pressure from the tanks, not flow rate, and the red indication (regardless of selector position, with two tanks known to be full) suggests that tank pressure was not reaching the changeover mechanism. Of course the changeover mechanism can fail, but that's different from the regulator needing adjustment.

My guess is that the excess flow valves in the tank hoses were tripped by the surge of propane flow when the tank valves were opened, and were reset simply by closing them and waiting long enough. This problem also occurs when propane tank pressure actually is too low due to the combination of low ambient temperature and chilling of the propane due to use.

Switching tank positions and disconnecting tank hoses are both unnecessary if the excess flow valves are tripped, but the time it takes to do these things allows the excess flow valves a chance to reset. After closing tank valves you can take the hoses or the whole tanks off and put them back on, or just stand there and admire the scenery... the excess flow valves will reset either way.

[tacchino]

Originally Posted by Brian B-P

The changeover mechanism is before the regulator portion of the combined "auto-changeover regulator" in the flow path. It responds to pressure from the tanks, not flow rate, and the red indication (regardless of selector position, with two tanks known to be full) suggests that tank pressure was not reaching the changeover mechanism. Of course the changeover mechanism can fail, but that's different from the regulator needing adjustment.

My guess is that the excess flow valves in the tank hoses were tripped by the surge of propane flow when the tank valves were opened, and were reset simply by closing them and waiting long enough. This problem also occurs when propane tank pressure actually is too low due to the combination of low ambient temperature and chilling of the propane due to use.

Switching tank positions and disconnecting tank hoses are both unnecessary if the excess flow valves are tripped, but the time it takes to do these things allows the excess flow valves a chance to reset. After closing tank valves you can take the hoses or the whole tanks off and put them back on, or just stand there and admire the scenery... the excess flow valves will reset either way.

Good point about the changeover mechanism coming before the regulator. I didn't realize there was any protection in the hoses themselves. I'll do some more testing, maybe you are correct and I just opened the valve on the DS tank too quickly.

[Greg A]

Originally Posted by tacchino

Good point about the changeover mechanism coming before the regulator. I didn't realize there was any protection in the hoses themselves. I'll do some more testing, maybe you are correct and I just opened the valve on the DS tank too quickly.

Possibly, but the problem with that is you indicated your fire pit was running and you noticed flames running lower. Normally, if you open too fast the tank valve will be blocked and you get no flow, by design. Definitely worth playing with the connections, etc., but if it doesn’t right the ship then I’d lean towards a defective regulator.

[Iowa Dave]

Originally Posted by Greg A

Possibly, but the problem with that is you indicated your fire pit was running and you noticed flames running lower. Normally, if you open too fast the tank valve will be blocked and you get no flow, by design. Definitely worth playing with the connections, etc., but if it doesn’t right the ship then I’d lean towards a defective regulator.

That’s been my experience and regardless of the exact physics in play here, over the years as I happened on to the described situation, through trial and error and using my logic, however convoluted, I have solved the no flow, low flow, low pressure, tired regulator, leaky system anomalies a number of times. If you work on the propane supply system at any time, always check for leaks. I like the specific leak detecting product with a dauber, it’s real definitive, really bubbles up well.
Iowa Dave

[Brian B-P]

Originally Posted by Greg A

Possibly, but the problem with that is you indicated your fire pit was running and you noticed flames running lower. Normally, if you open too fast the tank valve will be blocked and you get no flow, by design. Definitely worth playing with the connections, etc., but if it doesn’t right the ship then I’d lean towards a defective regulator.

Excess flow valves don't cut off flow entirely - they reduce it greatly. Still, if a fire pit runs at any significant level a regulator problem is more likely than a tripped excess flow valve. A regulator problem just doesn't explain the changeover device problem... and of course more than one problem can exist at the same time.