Propane discharge

mtnrv · 08-10-2015, 09:47 AM

I picked up my new 2015 Greyhawk in MI on Wed. On Sunday we were outside Denver when a extremely loud whooshing sound started and my wife said she smelled propane. I pulled over and shut off the propane, smell dissipated pretty quickly, the sound had stopped by the time I got the rv stopped. Today (Monday) I do a thorough inspection of the propane lines and fittings - I see nothing obviously broken or uncoupled. Could the apparent discharge been an overpressure situation some how and the sound was just coming from the relief valve? Any help would be appreciated. Wife is freaking out and a service appointment is 2 weeks out.

33 RLDS · 08-10-2015, 09:56 AM

Can you switch to the 2nd tank and check for major leak?

TWP723 · 08-10-2015, 10:05 AM

Quote:

Originally Posted by mtnrv

I picked up my new 2015 Greyhawk in MI on Wed. On Sunday we were outside Denver when a extremely loud whooshing sound started and my wife said she smelled propane. I pulled over and shut off the propane, smell dissipated pretty quickly, the sound had stopped by the time I got the rv stopped. Today (Monday) I do a thorough inspection of the propane lines and fittings - I see nothing obviously broken or uncoupled. Could the apparent discharge been an overpressure situation some how and the sound was just coming from the relief valve? Any help would be appreciated. Wife is freaking out and a service appointment is 2 weeks out.

Does it have a pressure relief valve? I've never know relief valves to be put on propane tanks. Just wonderin...

RedHorse1 · 08-10-2015, 10:11 AM

I don't think there's relief valve in a propane system. There is a pop-off plug on the tank valve but it's a one shot deal. Did one or both tanks empty?
I might suspect a broken or damaged gas line. If you have a hole in the system the automatic shut-off in the pig-tail connector will probably prevent much gas to flow, it's designed to shut the gas off at the tank connection if a high flow rate occurs.
Sounds like the propane detector did not go off, I'd check that too.
If you do any troubleshooting open the windows first and make sure nothing else is running (lights, fans, misc electric motors...-potential sources of ignition)

mtnrv · 08-10-2015, 10:17 AM

No 2nd tank on this model. I have opened the tank back up and will see if I have a noticeable leak or odor.

mtnrv · 08-10-2015, 10:21 AM

Well, maybe it's a plug not a valve. It's only marked "relief" so I assumed it was a valve like you'd find in a bicycle tire.

Robbbyr · 08-10-2015, 10:40 AM

Anything left in the tank?

mtnrv · 08-10-2015, 10:52 AM

Yea...still a bit over 1/2 full.

Side note - I see you are in Akron, we were just passing through there visiting wife's dad in Canton. Lots going on this past weekend in that area with the golf tourney and hall of fame game.

RedHorse1 · 08-10-2015, 11:40 AM

Will any of the gas appliances work, like the stove? If not it would raise my suspicion about a leak in the flexible gas line and the shut-off valve in the pig-tail has closed.

Robbbyr · 08-10-2015, 01:52 PM

I see some are asking you about the pigtail, which I believe is only present on towed RVs with changeable DOT propane tanks. Our Class C units have an onboard ASME propane tank, and I believe they do have a spring-loaded relief valve that will reset once it has "popped" and relieved the excess pressure.

It is possible the tank was very full in a cooler environment and once in a hotter environment it caused the liquid propane in the tank to gas off without enough available vapor space to accommodate it. Hence, a relief valve event.

You are right about Akron, we had the Bridgestone Invitational golf event at the famour Firestone Country Club here in Akron; the Pro Football Hall of Fame Induction Ceremony in Canton just to our south, and the Twinsburg "Twins Days" going on to our north. All draw people from many other areas to northeast Ohio.

mtnrv · 08-10-2015, 04:10 PM

I have left the valve in the open position all day with no noticeable leaks or odors. Your suggestion about a full tank in a cool environment dovetails with what I'm thinking. I was thinking if the tank fill level was high and the change in elevation of running to Colorado (plus the heat of the day) caused the relief valve to pop.

Murff · 08-10-2015, 04:24 PM

Murff

Jagiven · 08-10-2015, 04:38 PM

I am not very far Milan with the built in tanks. There should be a relief valve. It could have poped. But they are designed to handle a wide range of conditions. If the tank was filled at sea level and you went over a high mountain pass I might see it pop. But still there is not a lot of atmospheteic pressure change.I would crawl under the unit check the hoses. The turn the tank back on and check for leaks, using a strong soap solution. I like to use kid's bubbles, cheap and works good.

RedHorse1 · 08-10-2015, 05:12 PM

Quote:

Originally Posted by Robbbyr

I see some are asking you about the pigtail, which I believe is only present on towed RVs with changeable DOT propane tanks. Our Class C units have an onboard ASME propane tank, and I believe they do have a spring-loaded relief valve that will reset once it has "popped" and relieved the excess pressure.

It is possible the tank was very full in a cooler environment and once in a hotter environment it caused the liquid propane in the tank to gas off without enough available vapor space to accommodate it. Hence, a relief valve event.

You are right about Akron, we had the Bridgestone Invitational golf event at the famour Firestone Country Club here in Akron; the Pro Football Hall of Fame Induction Ceremony in Canton just to our south, and the Twinsburg "Twins Days" going on to our north. All draw people from many other areas to northeast Ohio.

Great point Robby. I was thinking a changeable tank. Reading the following posts it sounds like the riddle may have been solved. Am hoping so! Mtn, hope I didn't muddy the water too much.

wags999 · 08-10-2015, 05:27 PM

The pressure inside the tank does not change with elevation. If it was a tire, yes it is effected, but a steel tank is not effected. A hose could be effected but it is low pressure once it leaves the regulator.

**norty1** · 08-10-2015, 06:00 PM

Does the Greyhawk have a permanently mounted propane tank?

dougfir1 · 08-10-2015, 06:01 PM

Every propane tank has one. On a 20# cylinder it is located on the back side of the main valve. I am inclined to think the tank may have been sitting out in the hot sun and it built up too much pressure. In that it has not repeated may mean it was just doing its job. Have it checked by a propane service man.

us71na · 08-10-2015, 06:37 PM

All propane tanks are equipped with a safety valve. It sounds like yours got too hot and relieved the pressure. Modern tanks are also equipped with an overfill protection device (OPD) which prevents them being filled too full of liquid. It is possible your tank was overfilled despite the overfill protection by an inexperienced operator. Tanks have to have some gas space above the liquid so the liquid can expand when it gets warm. If the pressure gets too great the safety valve will pop. I believe that they automatically reset.

Robbbyr · 08-10-2015, 06:37 PM

A Greyhawk is a Class C motorized RV and has a permanently mounted horizontal ASME tank.

Is there a chance your propane tank is seeing excessive heat from an external source? On my former Class C (Thor Chateau) the propane tank was located right behind the cab. I had the outdoor sensor for my thermometer mounted to the access door to the tank. After driving for a time that thermometer would rise to 140 degrees! I ended up installing an additional heatshield on the exhaust pipe/catalytic converter and it improved it considerably.

**norty1** · 08-10-2015, 06:42 PM

Thanks, that is why I asked. I am sure it has a method of venting in case of over pressure. I have had them let off some pressure while transporting portable tanks home in my truck. After they equalized all was well.

The heat buildup may be something to check but I'm betting it will be ok to try some appliances to verify that all is well.

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