RV propane tank inspection: dates, valves, regulators and hoses

Three Julys ago I was on Highway 58 east of Bakersfield, headed up to Tehachapi for the weekend, when the rain started. Not a sprinkle, a real Central Valley gully-washer. Wipers on high, and I still couldn’t see the tanker ahead of me. That’s when it hit me: I hadn’t looked at my motorhome’s propane system since I bought the thing used in Surprise, Arizona, and I knew I should have gotten an RV inspection in Orange before heading out. The tank was full, the stove lit, but I’d never checked the regulator date or the hose for cracks. If a hose let go on that grade, I’d be pulling over with a fire I couldn’t outrun. I’m an RV inspector, and I’d been lazy with my own rig. That’s why I write this for owners who want a straight answer on RV inspection in Orange and everyplace else: propane doesn’t care if you’re an expert.

A good mobile RV inspection treats the propane system as a chain: tank, valve, regulator, hose, appliance, detector. Break one link and the gas either leaks or stops flowing. This post is your checklist for that chain.

I’ll show you exactly what I look at on a “RV propane tank inspection”, whether it’s my own Class A or a customer’s fifth wheel. And if you’re in California, in Las Vegas, or going to Austin, the same rules apply.

RV propane tank inspection: DOT cylinders vs. ASME tanks

DOT cylinders expire. The manufacture date is stamped on the collar near the valve. It’ll be a month and a year, like 03 17. That’s March 2017. A cylinder that is 12 years past that date needs requalification befor it can be filled, but check the collar for the most recent requalification stamp because the interval after that depends on the method used. After that, the interval depends on the method the requalifier used. If the collar says E, its good for 5 years. If it says S, 10 years. No letter, 12 years. These are the requalification intervals after the initial 12-year period.

What I check instead is the tank’s data plate and its mounting. That’s what the rest of this post is about.

How to read the cylinder date and when to requalify

My neighbor argued with me about his tank dates. The tanks went to the scrap yard and he bought two new ones.

Pull out the RV inspection checklist and write down the dates on your bottles. Put it in your phone. Set a reminder. It’s a five-minuite job. If you’re not sure about the stamp, take a photo and show it to a filling station. They’ll tell you.

Here’s a video that shows the basics of getting to know your RV propane tank.

Valves and OPD: what to check without a flame

Safety warning: Never use a flame to check for leaks. I don’t care if your grandpa did it. A spark plus a small leak equals a fire. Always, always, always use soapy water or a commercial solution. Shut the valve before you start spraying around any fitting you’re going to open. The gas will drain out of the line in a few minutes. Better to be safe than on fire.

One more thing on valves: the tank collar should be straight. If you’re not sure, have a propane dealer inspect it.

The regulator: age, vents, and why it fails

It’s a $30 part. Cheap insurance.

Safety warning: Don’t replace a regulator yourself unless you know what you’re doing. If you get the fittings cross-threaded or use the wrong kind of tape on a flare fitting, you can make a leak. Leave it to a qualified tech. The five minutes they charge is worth it. I once did a mobile RV inspection on a Class A in Surprise, Arizona. The regulator was still working but the body was half eaten by corrosion. The buyer used that to knock $150 off the price. Money well spent on the inspection.

The printable propane checklist

7. Compartment venting: The tank compartment should have a vent to the outside, but check your rig’s design because some compartments are sealed and rely on other ventilation. The vent should be clear of dirt, wasp nests, and cargo. I once found a bottle jack shoved under a tank, blocking the vent. The owner had no idea.
8. Inside detector: Test the LP detector, it should have a test button. Some beep, some flash. If it’s past the printed date, replace it. Do this at least twice a year, or every time you move the rig.
9. Appliances: Light the stove. Does each burner have a blue flame with no yellow tips? The oven should light. The furnace should fire and push warm air. The water heater on LP should fire. If any of them soots up or won’t stay lit, call a tech.
10. Leak test: With the system fully open, shut the tank valve. Watch the pressure gauge if you have one. If the pressure drops more then a hair in 5 minutes, you may have a leak, but a small drop can be normal as the system cools; confirm with a soapy water test. Close the tank valve and call for service.

Safety warning: Never use a flame to find leaks. Use a leak detection solution. If you smell gas or hear a hiss, shut the tank valve immediatly and get the rig inspected before using propane again.

Hoses and pigtails: cracks happen faster than you think

Others say 10. If you see a DOT marking, that’s the hose spec, not the date. The date is usually near the fittings. If there’s no date, replace it if it looks brittle or cracked. The pigtail on my own motorhome was original to the 2012 coach. When I bought it, the hose was still pliable, but I replaced it anyway because I didn’t know its history. It’s a $20 part. Less worry.

The other hose runs from the regulator to the copper tubing. On many rigs, it’s a flexible hose with a crimped fitting on one end and a flare on the other. It sees the same weather as the pigtail. Check it for cracks and chafing. If it rubs against the frame, it’ll wear through. Zip-tie it away from moving parts. A hose that’s missing its date code or is more than 10 years old should be replaced, but some manufacturers recommend replacement as early as 5 years, so check the hose condition and any printed date.

The LP detector inside: it has a lifespan too

What about the carbon monoxide detector? It’s separate. It usually mounts on the wall or ceiling. It also has a lifespan, but the numbers vary by brand. Check the printed date. The smoke alarm, too. They’re cheap. If you buy a used rig, replace all three detectors unless you can verify they’re new. The RV inspection checklist I use has a line for each one, and my report always lists the dates.

Safety warning: Never disconnect the LP detector to silence it. Never paint over it. Never put it in a cabinet. It needs to be near the floor, in open air, so it can smell the gas. If it’s expired, replace it with a new one that has the same mounting pattern. It’s a five-minute job.

What I’d do before you buy

This weekend, grab a flashlight and go out to your rig. Read the tank date. Look at the regulator vent. Spray some soapy water on the fittings. If you find a crack or a drip, shut it down and call a pro. If you want a secound set of eyes, find a certified or mobile inspector near you and ask if propane checks are included in thier standard inspection, and see our post on how much does an RV inspection cost to budget for it. Most of us do it as a matter of course. If they don’t, find another one.

More from the inspection notes

• RV electrical inspection: what gets tested from pedestal to outlet