Strange propane regulator vent leak

[Oranjoose]

I have two propane tanks connected through a changeover valve (picture attached). I close the tank I'm not using.

The left-side propane tank ran out last night, and so I opened the right-side tank (picture attached) and used a couple gallons keeping the rv warm overnight.

I then went out and filled both tanks, but when I re-mounted the tanks and opened the left-side tank, the right-side (as in the other side of the changeover) tank regulator's vent hole hissed out lots of propane.

With both tanks open, the right-side regulator hisses and leaks from the vent, same as if only the left-side is open. However, when the left-side is closed and the right-side is open, it doesn't hiss and is at least apparently not leaking. What is going on?

Is it that the changeover valve is broken because it shouldn't be letting left-side gas go to the right side, and the right-side regulator is bleeding out any pressure that is back-flowing? But isn't the hose pressurized as it is when appliances are off and so the regulator should handle back-flow? Or maybe it can't handle back-flow at unregulated pressure from the other side? But it was working fine before refilling the tanks.

Or is it that the right-side regulator suddenly failed? But it seems to not be leaking when the right-side tank is open (left-side closed) and appliances are using it.

Or is it that I somehow messed up while re-attaching the connections? I'm not sure how. And the right-side regulator also hisses and leaks even when the whole hose isn't attached to the right-side tank.

Does anyone have experience with this kind of problem?

 

[Kirk]

The regulator probably needs to be replaced as your symptom describes an internal propane leak.

 

[Rene T]

If it’s an auto change over regulator why don’t you leave both tank valves open? That’s the way they’re designed. It will save you from having to get up at 1:00 in the morning to switch tanks manually. Just make sure you check the indicator on the regulator in the morning to make sure one tank is not empty.

 

[Oranjoose]

If it’s an auto change over regulator why don’t you leave both tank valves open? That’s the way they’re designed. It will save you from having to get up at 1:00 in the morning to switch tanks manually. Just make sure you check the indicator on the regulator in the morning to make sure one tank is not empty.

Sure, but this problem happens whether or not they're both open.

It's hard to see the indicator lens based on where the autochangeover valve was placed.

 

[Oranjoose]

The regulator probably needs to be replaced as your symptom describes an internal propane leak.

So it's normal for the autochangeover valve to let propane go from one tank to the other?

To replace that right-side tank's regulator, I think I have to change the whole 12 ft hose it's crimped to, right? I bought that hose within the last year. If I buy a new one, would it work to buy one without a regulator, relying on the autochangeover valve's regulator?

 

[Lou Schneider]

The answer is simple. You have to move the auto changeover valve to point towards the opposite tank before you disconnect the empty one. If the valve is pointing towards the tank you're removing the hose will leak propane when you disconnect it. It won't the valve is pointing towards the opposite tank.

Leave both tank valves open with the changeover valve pointing towards one tank or the other. The tank it's pointing towards becomes the primary tank and will drain first, when it's empty the indicator will change from green to red and the valve will draw from the opposite tank.

 

[Oranjoose]

The answer is simple. You have to move the auto changeover valve to point towards the opposite tank before you disconnect the empty one. If the valve is pointing towards the tank you're removing the hose will leak propane when you disconnect it. It won't the valve is pointing towards the opposite tank.

Leave both tank valves open with the changeover valve pointing towards one tank or the other. The tank it's pointing towards becomes the primary tank and will drain first, when it's empty the indicator will change from green to red and the valve will draw from the opposite tank.

Interesting. But what do I do now? If I open both tanks, then the right-side tank spews propane from its regulator vent. No matter what the autochangeover valve is set to, if I open the left-side tank, it spews gas from the right-side regulator even if the right-side tank is totally disconnected.

 

[Kirk]

But what do I do now?

Replace it with one that is good.

 

[Oranjoose]

Replace it with one that is good.

The autochangeover valve or the right-side tank regulator? I'm not sure which isn't good. Is the regulator spewing because the autochangeover valve is bad?

 

[Rene T]

Change both of them. The right side one is very cheap.

 

[CharlesinGA]

Get a complete new auto change over regulator and new pigtails and be done with it. You have a Cavagna Kosan 924N RV Auto Changeover Regulator, Sixty bucks on Amazon. Yours is missing the clear changeover knob and indicator flags. Its an Italian design, made in China. Actually a decent regulator.

It will use pigtails with inverted flare, male thread to attach to the regulator (commonly used nowdays). Not sure how long yours are, 12"?, 15"?(likely), 24"(not too common if its under a cover)

You need TWO of these pigtails........................

Camco 15" Pigtail Propane Hose Connector, Connects Propane Cylinder To a RV or Trailer Propane Regulator, Provides Thermal Protection and Excess Flow Protection

DO NOT use any sealer or thread tape when installing these inverted flare pigtails. the flare does all of the sealing. You WILL need yellow gas rated thread tape on the 3/8 hose on the bottom of the regulator going into the trailer.

The autochangeover valve or the right-side tank regulator? I'm not sure which isn't good. Is the regulator spewing because the autochangeover valve is bad?

Not sure what you mean. there is ONE regulator, plus the auto change over, all together in one unit. Then the two tank pigtails. Unless it is some modified system, there is no "right side tank regulator".

EEK!!!!!!!!!

EDIT: I see now. What is that BBQ grill regulator in the first pic doing there? You should have HIGH pressure going into the auto change over and regulator unit. That extra regulator does not belong there. Take it off and throw it away! Read my Post # 17 below for more on this.

Should look sorta like this...................

This is my GO TO regulator. Made in the USA and works good, last long time. I won't buy any other.
Marshall Excelsior MEGR-253P-PT15 Standard Regulator and Hose Kit - 15" Pigtail

Charles

 

[Rene T]

I was thinking his set up would be like mine in my fifth wheel. I have a tank on the left side (drivers side) and a tank on the right side (passenger side). The passenger side has a regulator of its own and then the auto changeover valve above the drivers side has a regulator built in the assembly.

 

[Oranjoose]

Get a complete new auto change over regulator and new pigtails and be done with it. You have a Cavagna Kosan 924N RV Auto Changeover Regulator, Sixty bucks on Amazon. Yours is missing the clear changeover knob and indicator flags. Its an Italian design, made in China. Actually a decent regulator.

It will use pigtails with inverted flare, male thread to attach to the regulator (commonly used nowdays). Not sure how long yours are, 12"?, 15"?(likely), 24"(not too common if its under a cover)

You need TWO of these pigtails........................

Camco 15" Pigtail Propane Hose Connector, Connects Propane Cylinder To a RV or Trailer Propane Regulator, Provides Thermal Protection and Excess Flow Protection

DO NOT use any sealer or thread tape when installing these inverted flare pigtails. the flare does all of the sealing. You WILL need yellow gas rated thread tape on the 3/8 hose on the bottom of the regulator going into the trailer.



Not sure what you mean. there is ONE regulator, plus the auto change over, all together in one unit. Then the two tank pigtails. Unless it is some modified system, there is no "right side tank regulator".

EEK!!!!!!!!!

EDIT: I see now. What is that BBQ grill regulator in the first pic doing there? You should have HIGH pressure going into the auto change over and regulator unit. That extra regulator does not belong there. Take it off and throw it away!

Should look sorta like this...................

This is my GO TO regulator. Made in the USA and works good, last long time. I won't buy any other.
Marshall Excelsior MEGR-253P-PT15 Standard Regulator and Hose Kit - 15" Pigtail

Charles

Wow thanks for the informative reply. The right-side pigtail is 12 feet long. It's something like this: https://a.co/d/3CmGv2c



Should I first try to replace the 12 ft regulator pig tail with a 12 ft one that doesn't have a regulator, and attach that to the existing changeover valve, and see if that works?

The flare on the pigtail seems to be opposite the compatibility of how most changeover valves are made nowadays though. That is, the pigtails attach female to the existing changeover valve.

 

[CharlesinGA]

Why do you need a 12 ft hose? Is this not two tanks sitting side by side in a rack? In any case you do not want that extra regulator in the hose, its messing with your flow.

Explain the layout of the system or post up some pics. This is weird to say the least. The regulator looks like its screwed to the underbelly judging from that material behind it.

If you absolutely have to, you could use a HIGH PRESSURE rated 12 ft hose. Even with a new regulator, you could swap fittings in the side of it from your old one to hook up the hose. You won't find a 12 ft hose with the male/inverted flare end.

And yes, I blew up your second pic and spotted the 924N on it and figured out what brand it was. Clearly something was missing (and is).

Charles

 

[John From Detroit]

The two tanks have DIFFERENET regulators.. Very rare. Very odd

usually the two tanks feed a selector valve and then IT feeds ONE regulator. The valve has no vent. only the regulator has a vent.. Venting indicates high pressure on the outlet side from a different regulator.

 

[SMR]

This is our set up, regulator on door side tank. The regulator in pic 2 went bad and was leaking out propane, replaced and all is good. I didn't look at the change over valve at the time so no help there.

 

[CharlesinGA]

This is our set up, regulator on door side tank. The regulator in pic 2 went bad and was leaking out propane, replaced and all is good. I didn't look at the change over valve at the time so no help there.

I wasn't aware of a "split fifth wheel lp system" but a little research tells me yours is done that way. The auto change over/regulator on the left takes ~250 psi from the tank attached to it and makes ~0.4 psi/11 in WC for the trailer's system, -- OR -- it takes ~250 psi tank pressure reduced by the high pressure RED regulator to ~10 psi to send it a "long distance" to the auto change over valve and the built in regulator, which reduces it further to the final pressure of ~0.4 psi/11 WC for the trailers system. This avoids sending full tank pressure a long distance (which becomes a safety hazard) and reduces it to a lower/safer intermediate level using the RED regulator.

From looking at catalogs, mostly the MEC Camping and RV catalog (as it is extremely informative and not just a catalog) I see that high pressure regulators used as the intermediate regulator in a system like this is always going to be painted RED. The auto change over regulators are two stage, internally they drop the pressure to a level the final diaphragm/stage can work with and maintain a consistent ~.04/11 WC pressure.

The OP needs to tell us what kind of trailer and LP system they have. Its possible someone in the past replaced a RED regulator with what I refer to as a BBQ grill regulator (it ain't red) and this puts final pressure onto another regulator which is also trying to make final pressure, messes with the flow. As far as the OP's problem, I'm betting he has some defective parts (and for sure some broken ones).

Charles

 

[CharlesinGA]

I was thinking his set up would be like mine in my fifth wheel. I have a tank on the left side (drivers side) and a tank on the right side (passenger side). The passenger side has a regulator of its own and then the auto changeover valve above the drivers side has a regulator built in the assembly.

Which is the same as the system SMR has in post #16, Butttttttt...... that stand alone regulator is different, as I described above, which is why the system works.

Charles