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RV Tech Q&A: March 2019

Originally Published in Trailer Life Magazine

Refrigerator Operation

Red letter QWe just bought our first RV, a 2015 Keystone Outback Super Lite fifth-wheel, and are learning things every time we get in or go somewhere. I have a problem with the refrigerator. After returning home from the last camping trip, we hooked up to 30-amp power to keep everything working, but the “Check light” on the refrigerator keeps coming on.

I looked up in the only paper I have on it, and it tells me to turn it off for 10 seconds and then turn it back on, and the light will go off. I have done this 100 times, it seems. I have been told that I need to leave the gas on, and it will automatically use whichever it needs, and it did. It drained the cylinders down pretty quick. Then someone else told me that when I have it hooked up, I shouldn’t have to turn the gas on.

Marty Belcher | via email

Green letter A

Hi, Marty, and welcome to the RVing community! First, since you’re new at this RV gig, I’d recommend you navigate online over to our Trailer Life FAQ page. While you’re on the Trailer Life website, I’d also recommend you look at the drop-down Tech menu, then choose the Tech Q&A section. On those pages you’ll find a wide variety of technical questions and answers, many that are similar to your question, that are derived from our RV Clinic column.

That “Check light” you’re seeing is part of the refrigerator’s LP-gas power system. It lights up when there’s an incomplete startup in the combustion cycle or when the unit is running on LP-gas and something happens that causes the burner to shut down. If you were running on LP-gas, it could mean the cylinders are empty.

You didn’t say which model of refrigerator you have, but if it’s an Automatic Energy Selector (AES) type, it automatically chooses the best available power supply and uses that. You can learn more about that from the owner’s manual or the manufacturer’s website. The fact that the fridge keeps turning on the Check light suggests you don’t have an AES model. Try manually switching it to AC power and see if that works. Again, the owner’s manual is your friend.

If you have the trailer plugged in, and it won’t work on AC-power mode, check the power receptacle in the refrigerator compartment and see if there is power there. If so, and the refrigerator is plugged in, it’s possible that the 120-volt AC fuse on the circuit board is blown and/or there is a bad AC heating element.

Dirty Tank Sensors

Red letter QHow can we clean the sensors for the holding tanks, as they are misreading? I have heard this can be caused by debris sticking to the sensors, giving false readings.

Larry Fister | Merced, California

Green letter A

You’re right, Larry, debris builds up on the sensors over time, and that creates false tank-level readings. There are several sensor cleaners on the market, and one that we’ve heard some very good things about is Thetford’s Tank Blaster, a fairly new product. Another is Thetford’s Level Gauge Cleaner, which is used as a regular maintenance item. Both Thetford products are readily available at RV-supply stores and dealers.

You may also see online references to various mechanical solutions — such as using ice cubes to slosh around in the tank and knock some debris loose — and these work to varying degrees of success. You may find the chemical solutions are all you need. For a more permanent solution, you can consider replacing the existing sensors with Horst Miracle Probes or switch to a system like the SeeLevel II from Garnet Instruments.

More Black-Tank Valve Leaks

In January’s RV Clinic, I read with interest Kevin Kobus’ problem with his Jayco hybrid trailer’s leaking black-water valve. I had the same problem on my Dutchmen. I was going to replace the valve block, which would mean cutting through the discharge tube to unbolt the back two bolts.

I then found that the small rod attached to the push/pull cable was cut too short by about ½ inch and would not fully push the gate valve closed. Bouncing down the highway caused the valve to open even farther. What a mess!

I used some farm-boy engineering and cut a small bolt to length, drilled a hole, welded it to the OEM shaft, thus extending it, then rehooked it to the wire. It works perfectly.

Larry Amstutz | Grand Haven, Michigan

Thank you for passing that along, Larry. It’s terrific that you found a way around the improperly sized valve-operating cable and were able to engineer what sounds like a good solution to the problem. You may well be causing some readers to head under their RVs to see if your solution will help them as well.

Have a Tech Question?

Email [email protected] and include your full name and hometown. Selected letters will be answered in the monthly RV Clinic column, but time does not permit individual replies.

Man with grey beard and wearing blue shirt leaning over open car hoodJeff Johnston served as technical director of Trailer Life for 20 years and has been an RV enthusiast, mechanic and writer since he could hold a wrench. In his monthly RV Clinic column, Jeff replies to Trailer Life readers’ technical questions about RVs and tow vehicles. He also serves as associate producer of Rollin’ On TV, a nationally syndicated television program for RV enthusiasts.

diyJeff JohnstonRV ClinicRV DIYRV Questions and AnswersRV Tech

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