Saturday, April 1, 2023


LP alarm goes off even when LP tanks are closed

Chris Dougherty responded to this reader when he was’s technical editor.

Dear Chris,
My LP tanks are shut off. The LP alarm activates and will not stay off. I’ve checked for leaks (with soapy water) – no leaks at the lines. I also replaced the heavy-duty battery (although it wasn’t dead, it did test weak). The sensor indicates it should be replaced if test light is yellow, and not red. I’m getting an orange glow. Before I invest in a new sensor I would appreciate your input… I can’t find a manufacturer’s date on this unit. —Chuck

Dear Chuck,
I think what you’re looking at is a defective LP gas detector. The orange glow is actually the yellow that they describe. I’ve seen this many times. Despite all the testing you did, which is a good thing, the giveaway is that the detector continued going off even when the LP gas was shut off. Also, enough gas to set off the detector is usually enough for most people to smell it, but as some folks can’t smell the odorant, and no one can smell it when they’re sleeping, the detector is a necessary safety buffer.

As far as the date is concerned, the detector is malfunctioning, so the date is irrelevant. Should your new detector not have a date on it, you can add it to your coach’s maintenance log that you installed in and when. Check the manufacturer’s instructions for a projected replacement date, and how to properly install it.

Replacement RV LP detectors are available from your favorite RV parts and accessories store or Amazon.


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2 years ago

I think Chris may have missed an important part of a complete answer. In addition to propane, an LP detector will detect LOTS of things, mostly aerosols. Have you recently used hair spray? Spray deodorant? Bug spray? Some spray paints? Bathroom spray? So-called “canned air” for cleaning a keyboard or whatever? Some asthma inhalers? Spray (or even pump bottle) perfume or scent? You get the idea. Replacing your detector on the suggested schedule is a good idea, but if you haven’t reached that time yet, try opening the windows and airing the place out – just as a check.

2 years ago

Once you’ve decided you need to replace it, there is still homework to do. Your detector probably controls a solenoid propane shut-off valve, to stop the leak as well as alert you that one exists. And that valve may well have to be replaced with a new detector, as the wiring scheme may not be the same. This is a job that CAN be DIY, but unless you’re confident with wiring and propane equipment, you might want to have an expert do that installation for you.

2 years ago
Reply to  Don

In Motorhomes that have solenoid devices, NOT all do and Travel Trailers and 5th Wheels rarely do! It would be an option.

2 years ago

For those RVers who have had this happen: I hope you investigated the situation and either repaired the problem or replaced the detector!

LP Detectors are hardwired into your RV, (meaning power is always on to them, for safety)

Please don’t disconnect the LP Detector from your 12 volts!

There are too many people who have done this and unfortunately WOKE UP Dead!

2 years ago

This exact scenario happened to me last year!

My LP Detector kept going off in my RV with no Propane on!

Fortunately, we have a Propane Company that came out free of charge and checked all my connections and LP Tanks. No Problems found.

Bottom Line: It was the LP Detector that had gone bad. Looking at the date on the back of the detector, it was only 4 years old. So, they do go bad and fail. We have had no problems since!

I ordered a new one and the company sent me a unit that was already 3 years old from Date of Manufacture. I sent it back and they sent me a newer unit, manufactured in 2018.

These are replaceable items that any RVer can do. Just make sure the DATE of manufacture is close to a current date you are buying them. You need to look on the back of the unit and see the date on it. And remember it is not the date you purchase the unit, but the date the actual detector was manufactured.

Also, Mark on the Detector the Date of Replacement

Paul S Goldberg
2 years ago
Reply to  Really

I mark the expiration date on the face of the detector either with a label or with a sharpie. I see it every time I go by it. Plan to buy a new one 6 months before the date.

2 years ago

Depend what type it is. I have carbon monoxide/ lap gas detector which may show different color to detect what alarm may goes for.

2 years ago

Our LP detector alarm kept going off when the tanks were closed. It turned out our battery charger failed On and was cooking our house batteries. The hydrogen gas set off the LP alarm.

2 years ago

Replace the detector every 10 years. They do age out.

2 years ago
Reply to  Tom

Actually the LP Detector along with CO detector need to be replaced every 5 to 7 years.

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