Propane regulator vented air then stopped

[SMR]

I have 2 tanks and only have one open at a time. Tonight when I opened the valve on the tank air started coming out of the regulator, since I didn't smell propane I let it go for a bit and then it stopped.
To be safe I closed the valve and swapped tanks.
I've never had this happen before did the valve go bad?
Thanks

 

[Mr Lars]

Possible, did you open the valve really, really slow?

 

[SMR]

Yes

 

[Tulecreeper]

I have 2 tanks and only have one open at a time. Tonight when I opened the valve on the tank air started coming out of the regulator, since I didn't smell propane I let it go for a bit and then it stopped.
To be safe I closed the valve and swapped tanks.
I've never had this happen before did the valve go bad?
Thanks

If you have an auto changeover valve, why do you not have both tanks open at the same time? That's the way they are supposed to work.

 

[CharlesinGA]

Something about this seems familiar from another thread on this or another forum, back in the past.

This is a 5th wheel trailer, correct? How many cylinders is it supposed to have, 2? or 3?

Does it have an auto change over regulator in addition to the regulator you are showing?

Charles

 

[SMR]

Yes on the 5th wheel and 2 cylinders. Pic of the set up below.
I have the auto change over, we don't use propane that often so I like to know when one of the tanks runs out.

 

[Gary RV_Wizard]

If you have the auto-change regulator in the right (propane_1) photo, what's the red one on the left (propane_2)?

In any case, a regulator can't vent anything that is not already in the tank feeding it. How did you get a propane tank that had air in it instead of propane? Or was it maybe just a very empty tank with so little propane vapor that you didn't notice the smell?

 

[SMR]

The red one is a regulator, the propane tank at the red regulator was full.
I haven't used the tank with the red regulator in over a year, the camper was in for warranty work at the factory April 2023, could they have done a pressure check on the propane lines and introduced air into the system?
I keep the auto change over switch flipped to the tank I use if that makes a difference.

 

[Gary RV_Wizard]

I know the red item is a regulator. I'm curious why you have a separate regulator there when you already have a dual setup. Is there only one tank hooked to the dual tank changeover/reg? Why not have both on the dual system? You can still have one of the tanks shut off using the tank valve.

The red regulator should only vent whatever gas is in the feed tank or the line between tank & regulator. It shouldn't be venting from the rest of the line (and would have vented that long ago if it was). You said the venting started when you opened the tank valve, right? So it's not pressure elsewhere in the gas system - it came from the tank.

 

[CharlesinGA]

Where does the line from the red regulator go, and where does the line in the pic below go.

Red regulators are usually high pressure regulators that reduce the cylinder pressure to about 30 psi. There is no low pressure regulator. Is the manufacturer running the 30 psi gas to a rear kitchen where it is reduced to 1/2 psi for appliance use?

I've seen this before, but cannot remember how it was set up.

Charles

 

[Tulecreeper]

Where does the line from the red regulator go, and where does the line in the pic below go.

Charles

Very good point. It should be connected to the other propane tank.

 

[Tulecreeper]

Yes on the 5th wheel and 2 cylinders. Pic of the set up below.
I have the auto change over, we don't use propane that often so I like to know when one of the tanks runs out.

I think the main question everyone wants to know is: Why is there a second (red) regulator connected into the system. The one regulator that is also your changeover valve is all you need for your entire system. Unless that line with the red regulator is something that was added to power a stand-alone propane appliance.

 

[Lou Schneider]

I know the red item is a regulator. I'm curious why you have a separate regulator there when you already have a dual setup. Is there only one tank hooked to the dual tank changeover/reg? Why not have both on the dual system? You can still have one of the tanks shut off using the tank valve.

The red regulator should only vent whatever gas is in the feed tank or the line between tank & regulator. It shouldn't be venting from the rest of the line (and would have vented that long ago if it was). You said the venting started when you opened the tank valve, right? So it's not pressure elsewhere in the gas system - it came from the tank.

5th wheels with propane tanks on opposite sides often have an intermediate regulator on the far tank so you aren't taking full pressure propane across the width of the trailer. Usually it drops the pressure to 10-20 PSI.

The changeover regulator still works normally since it will switch when the pressure in the active tank drops below that.

The handle on an auto change
over switch has to point towards the active tank before you remove the empty one. If its pointing towards the empty tank it will leak gas when you disconnect the hose.

 

[SMR]

Where does the line from the red regulator go, and where does the line in the pic below go.

Red regulators are usually high pressure regulators that reduce the cylinder pressure to about 30 psi. There is no low pressure regulator. Is the manufacturer running the 30 psi gas to a rear kitchen where it is reduced to 1/2 psi for appliance use?

I've seen this before, but cannot remember how it was set up.

Charles

That hose goes to the red regulator this is how it was set up by the rv manufacturer.

 

[SMR]

I think the main question everyone wants to know is: Why is there a second (red) regulator connected into the system. The one regulator that is also your changeover valve is all you need for your entire system. Unless that line with the red regulator is something that was added to power a stand-alone propane appliance.

This is how it was set up by the rv manufacturer.

 

[CharlesinGA]

I dont think that will work. The red regulator only reduced the pressure to about 30 psi. The auto change over regulator also has a high pressure regulator in it to reduce the pressure to about 30 psi then, the large diaphragm reduces it to 1/2 psi, That would make the red regulator redundant. Are both cylinders in the same compartment? the hose leaves the red regulator and passes back thru the bulkhead out of sight. From the pic I cannot see what the LH hose of the auto change over regulator does.

See the links in my next post.

Charles

 

[CharlesinGA]

OK, Yours was the system I recall discussing before HERE is your discussion and HERE is my discussion.

Not sure why the regulator vented, but I think I would play with it some more before I would condemn anything.

This Forest River 5th wheel forum discusses this type of system. The codes do not allow runs of high pressure (tank or cylinder) beyond a certain distance, so the red regulator is designed to reduce it for this long run.

Charles

 

[Gary RV_Wizard]

Thanks to those who explained why the extra red regulator exists. Makes sense. But still doesn't explain how it could suddenly vent air (or whatever it was).

 

[Lou Schneider]

Thanks to those who explained why the extra red regulator exists. Makes sense. But still doesn't explain how it could suddenly vent air (or whatever it was).

Did it vent from the regulator or from the hose going to the propane cylinder when it was disconnected? The latter can be explained by the changeover switch being in the wrong position when the empty tank was disconnected.

 

[Ray-IN]

No, air cannot be introduced into an LP system when checking water column pressure, as WC pressure is measured by attaching a 1/8" plastic hose to the normally-capped regulator pressure test outlet/nipple.
If you left the remote mounted cyl. hose unattached for a long period it could drain of LP(which is heavier than air) and be replaced by air.
BUT, nowhere in an LP system is their a detector to differentiate between LP and air, which means it cannot only vent air.
Propane is approx. twice as heavy as air but the actual weight of one molecule is difficult to assertan. ref: Molecular Weight of Substances