LP issue? Maybe?

[Acdii]

I noticed that if I am not using the gas as in the water heater or refer, but keep the tanks open, and go to switch the refer to gas, that it errors and I have to turn on a burner for a bit to get gas flowing again, and can take up to a minute before I get a burner to light, and of course then the refer will work and stay working until I plug in AC. Now I know it isn't leaking, or my tanks would be empty by now and I haven't filled them since I bought the trailer in 2016. Each tank is about half full, I tend to switch tanks back and forth with the auto switchover manual switch. Quite puzzling.

[Acdii]

Old-Biscuit wrote:

Acdii wrote:

Old-Biscuit wrote:
When NOT using any propane for extended periods and Propane is valved for service then LP Reg goes into 'Lock-up' condition (normal)

What this means is W/O propane demand the reg can NOT hold 11" WC and pressure will rise...reg then goes into 'lockup' to prevent over-pressurization of system

Then you have to place a 'demand' on system.....lowers system pressure/reg then controls pressure & flow.
Can take a few minutes to fill ALL lines in propane system as each appliance attempts to light off.



OPD only stops flow of liquid into cylinder during filling processat 80% liquid level
OPD will NOT stop flow of vapor out of cylinder thru service valve

*Excess Flow Limiting Check Valve inside the ACME Green Nut CAN trip if service valves are opened too fast

Ah, this makes perfect sense then.I just wonder what happens to the flammable gas that is already in the line, I can hear it escaping through the burner. Since I never shut the tanks off unless I am changing one, and still have plenty of gas, I know it isn't leaking anywhere, so guess the only puzzling part is what happens to the gas in the lines when the reg shuts down?

The WHOLE LP System downstream of reg is only at 11" WC (0.4 psi)
And there is NO FLOW
When you first place a demand (stove top burner, fridge/water heater/furnace etc)on system the line pressure drops faster then Reg can respond and begin controlling pressure.
Air/fuel ratio is out of whack UNTIL that controlled flow is established and reg is controlling system pressure
(air/fuel ratio for propane is very narrow range)

My house is propane, and I have installed 2 furnaces, and 3 tankless water heaters, and have the WC gauge for checking pressure. Normally when I shut off the flow at the tank, it doesn't take long at all to get gas to the appliance, and I have a really long house. On the trailer though I keep the tanks open all the time, only close the valve if I pull a tank off. If there was a leak I am pretty sure I would know it since it is stored in my barn during the winter, and the tanks were open too in case we needed to use the furnace for whatever reason.

So if I am understanding correctly, when no demand is placed on the system for a length of time, the regulator basically shuts down, and whatever is in the line purges the moment a valve is cracked open, say when the refer is switched on just before power is applied, not long enough for the regulator to sense the pressure drop, so when I open a burner, there isn't enough gas in the line, even though I can hear it, until the flow from the regulator reaches 11" and has full fuel flow. Whatever is in the line is not enough to burn, or smell.

[Old-Biscuit]

Acdii wrote:

Old-Biscuit wrote:
When NOT using any propane for extended periods and Propane is valved for service then LP Reg goes into 'Lock-up' condition (normal)

What this means is W/O propane demand the reg can NOT hold 11" WC and pressure will rise...reg then goes into 'lockup' to prevent over-pressurization of system

Then you have to place a 'demand' on system.....lowers system pressure/reg then controls pressure & flow.
Can take a few minutes to fill ALL lines in propane system as each appliance attempts to light off.



OPD only stops flow of liquid into cylinder during filling processat 80% liquid level
OPD will NOT stop flow of vapor out of cylinder thru service valve

*Excess Flow Limiting Check Valve inside the ACME Green Nut CAN trip if service valves are opened too fast

Ah, this makes perfect sense then.I just wonder what happens to the flammable gas that is already in the line, I can hear it escaping through the burner. Since I never shut the tanks off unless I am changing one, and still have plenty of gas, I know it isn't leaking anywhere, so guess the only puzzling part is what happens to the gas in the lines when the reg shuts down?

The WHOLE LP System downstream of reg is only at 11" WC (0.4 psi)
And there is NO FLOW
When you first place a demand (stove top burner, fridge/water heater/furnace etc)on system the line pressure drops faster then Reg can respond and begin controlling pressure.
Air/fuel ratio is out of whack UNTIL that controlled flow is established and reg is controlling system pressure
(air/fuel ratio for propane is very narrow range)

[enblethen]

You could have a minute leak.
Could be a regulator or one of the LP devices.
It does not take much to drop the regulated output.
And yes I said OPD and should have said excess flow!

[Acdii]

Old-Biscuit wrote:
When NOT using any propane for extended periods and Propane is valved for service then LP Reg goes into 'Lock-up' condition (normal)

What this means is W/O propane demand the reg can NOT hold 11" WC and pressure will rise...reg then goes into 'lockup' to prevent over-pressurization of system

Then you have to place a 'demand' on system.....lowers system pressure/reg then controls pressure & flow.
Can take a few minutes to fill ALL lines in propane system as each appliance attempts to light off.



OPD only stops flow of liquid into cylinder during filling processat 80% liquid level
OPD will NOT stop flow of vapor out of cylinder thru service valve

*Excess Flow Limiting Check Valve inside the ACME Green Nut CAN trip if service valves are opened too fast

Ah, this makes perfect sense then.I just wonder what happens to the flammable gas that is already in the line, I can hear it escaping through the burner. Since I never shut the tanks off unless I am changing one, and still have plenty of gas, I know it isn't leaking anywhere, so guess the only puzzling part is what happens to the gas in the lines when the reg shuts down?

[jplante4]

It takes me a couple of minutes of trying to start the stove every time I get the coach going. We go at least once a month so yes, this is normal. After I get the stove running correctly, it still takes a couple of tries to get the refer going.

[Old-Biscuit]

When NOT using any propane for extended periods and Propane is valved for service then LP Reg goes into 'Lock-up' condition (normal)

What this means is W/O propane demand the reg can NOT hold 11" WC and pressure will rise...reg then goes into 'lockup' to prevent over-pressurization of system

Then you have to place a 'demand' on system.....lowers system pressure/reg then controls pressure & flow.
Can take a few minutes to fill ALL lines in propane system as each appliance attempts to light off.



OPD only stops flow of liquid into cylinder during filling processat 80% liquid level
OPD will NOT stop flow of vapor out of cylinder thru service valve

*Excess Flow Limiting Check Valve inside the ACME Green Nut CAN trip if service valves are opened too fast

[MitchF150]

Yes.. I've had my trailer for over 15 years and every time I shut off the gas, I have to purge the air out of the gas lines thru the stove top to get the fridge to fire up.

Actually, my routine is turn on both valves on the tanks. Go in and turn on the hood fan, then turn on all 3 stove top burners. With my "clicker" as I call it, I hold it on the middle burner until it lights.. Usually take a minute or longer. Then I light the other. I let them all run for another minute or so. Turn them off, then I try to light the HW tank. It's at the very end of the trailer, so the farthest away.

It might take a couple of tries for it to fire, but it will fire. I let it run for a minute or so too.

Then I light the fridge. It will then light on the first try.

I do not have a gas leak... It's just kinda like a helium balloon... After some time, it does not float anymore, but it's still inflated. Inert gas or something like that I guess?? Dunno. Just the way it is. 🙂

Mitch

[Acdii]

So this is something normal? I doubt we will camp this year due to truck issues, my current truck cannot handle towing like my last one did, even though it has 113 more pounds of payload. It has EPAS issues that can't be resolved and the truck likes to change directions at will. So for now I am just keeping it clean and making sure all is working correctly, as nothing ever lasts long when not being used. Just spent $200 to put in new electrical line to keep the lights on. If something is wrong, now is the time to get it fixed.

[MitchF150]

Yes, that's just what happens... If you still have gas in the tanks since 2016, then you don't use much gas...

I have to turn on my stove top between trips of about 3-4 weeks to get the HW and the fridge to start up quicker..

My HW is only gas, so no choice there.. I choose to only run gas on the fridge, so I go thru 2 tanks of propane a year on average. It's only 5 long weekend trips a year, so no big deal for me.

Good luck!

Mitch

[enblethen]

My first idea is the OPD valve is closing for some reason. Could be that you are turning the valves on too fast.