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Ask Dave: Doesn’t my LP tank have an excess flow valve?

Dear Dave,
On the propane tank, isn’t there a safety valve that shuts the tank off if there’s a sudden leak such as a ruptured line? Also, you mentioned open flames used on appliances. I believe that on mine there is no open flame; they have a sparker. —Ben

Dear Ben,
There is an excess flow valve designed into the connecting hose used on both ASME tanks for motorhomes and DOT cylinders of travel trailers and fifth wheels. It is a spring-loaded needle valve that will sense excess pressure due to a leak and shut off the flow until the system can backflow and release the pressure.

This can happen not only when there is a leak, but also if the valve is opened too quickly. It can take more than 10 minutes for pressure to be reduced enough for it to go back to normal operation.

Safety valve does not always shut off

One issue with this type of safety valve is that it will not shut off if you have a leak that is the same pressure as an appliance being used. For example, if a fitting to the stove or refrigerator loosens and there is a slight leak, it will not close as it senses the same pressure as the appliance would be using. Same for a small crack in a copper hose which can leak LP inside the rig that can pool in a refrigerator compartment.

GasStop is a safety valve that has been introduced to the RV market recently and was featured by Tony Barthel last August. Read about it here.

As for the open flame, an LP appliance such as the refrigerator, water heater, or furnace will have an open flame after the spark ignitor light it. When the refrigerator control panel calls for cold, the gas valve opens and the spark ignitor (sparker) clicks and throws a spark into the burner tube. That ignites a flame that burns continually as it heats the rich liquid and turns it into a vapor. The vapor goes up the tube to the evaporator coils of the cooling unit. Same with the water heater and furnace. You can see the flame of the refrigerator by swiveling the cover of the burner assembly shown in the lower right of this photo.

I recommend shutting the valve off when traveling

Granted, they do not run all the time, and if you have direct spark ignition (DSI), you do not have a pilot light going at all times. However, you will have a flame burning occasionally for quite some time. This can be dangerous not only if you have an LP leak, but also when pulling into a fueling station. That is why I recommend shutting the valve off at the tank or cylinder while traveling.

I know there are a great number of RVers that have traveled with propane on and never had an issue. However, I don’t want to be the one that does.

Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.

Read more from Dave here

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Carl
2 months ago

Yes, Weber grills can be converted to low pressure as they have a separate flow control and run at the same pressure as the appliances in the trailer. The regulator must be removed which can be done by anyone with a minimum amount of mechanical ability. However, the male fitting that plugs into the female low pressure quick detachable fitting must be a low pressure fitting. These fittings come in both high pressure and low pressure and although they look the same on the outside, there are internal differences which make low pressure or high pressure fittings not work with fittings of the “opposite s*x.”

Thomas D
7 months ago

Half right answer! If you shut off gas, dont forget to turn off refrigerator and DSI to water heater. They will call for heat or cool and spark untill it lights. You don’t want that spark at the fuel pump.

Dan
7 months ago

I used propane heaters in my work vehicles, but I would NEVER move them with the propane on. Not even across a parking lot. It’s just not worth the risk. I think anyone that does is foolish, right there with the people that still smoke while filling a vehicle with gas.
I agree that 12 volt makes the most sense for refrigerators. I wish I had one.

Richard
7 months ago

You recommend shutting propane while on the move. I wholly agree but would point out that many RV refrigerators, even new ones, only run on 120v or propane. A long drive in hot weather could certainly raise the temperature of many of these units. In this era of lithium batteries and inexpensive solar panels, it seems insane that propane refrigerators are used at all in new units. It is time to phase out these inherently dangerous devices. 12 volt compressor refrigerators cost less to buy, cool down quickly, require no venting (allowing a better-insulated unit AND less access for critters) and offer more capacity in the same space. Only downside is slight noise that is mitigated by “night mode”.

Bob p
7 months ago
Reply to  Richard

Amen

Tommy Molnar
7 months ago
Reply to  Richard

12v compressor fridges take quite a bit of power, more than your average battery bank can sustain. Not everyone can spend $2000 on a couple of Lithium batteries. And that’s just the start. Your converter has to be set up to charge Lithium batteries. So would your solar controller if you have solar. Having said all that, compressor fridges (like the ones we have at home) are much better at cooling stuff.

Scott R. Ellis
7 months ago
Reply to  Tommy Molnar

Actually, if you look at the numbers, the new compressor fridges designed for RVs and boats (and really quite NOT “like the ones we have at home”) don’t use much power at all. Certainly don’t require massive lithium battery banks. Next fridge in our truck camper will be that; only question is whether I wait for the existing propane unit to die, first, or just chuck the POS.

Dave
7 months ago
Reply to  Scott R. Ellis

I still have my POS, although I changed it to a 12 volt compressor unit a coule of years ago. No change in batteries. It runs on the same voltage as a dome light would. Check with Amish Refrigeration, they are great !!!

Tommy Molnar
7 months ago
Reply to  Dave

Voltage doesn’t matter. 12 volts is 12 volts. It’s the wattage and amperage that tell the story. I doubt the wattage of a dome light is the same as the wattage of a compressor fridge. I could be wrong . . .

Bob p
2 months ago
Reply to  Tommy Molnar

What? You mean there is more than volts when talking about electricity? I do declare, learn something new everyday. Lol

Jesse Crouse
2 months ago
Reply to  Bob p

Just ask Mike S. Or read any of the numerous articles he has written. You are spot on Bob p.

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