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RV Q&A: Mice Intrusion

Originally Published in Trailer Life Magazine

Red letter Q
We have a 25-foot Airstream Safari that mice are getting into. We have stuffed the tongue with steel wool, a suggestion from a service/restorer of Airstream travel trailers, but they are still getting in. I don’t see any holes or places of entry. The bottom is all aluminum covered, and there are no damaged or broken areas. Do you have any suggestions?

Chris Hart | Attica, Michigan

Red letter Q
Has no one ever experienced a rodent problem in their RV? I don’t recall seeing any letters bemoaning the nastiness they discovered in their units. I have found droppings in drawers, partially eaten packages and nests in the basement storage area of my fifth-wheel. In a cold-weather campsite, my RV’s converter failed because a mouse had found a warm place to do its “duty.” Why have RV manufacturers not been able to seal off vermin entry points to the interior living space of the units they build?

Barry Ulrich | Ozark Missouri

Green letter AMice have been getting into RVs ever since there have been RVs. The presence of the aluminum belly on your Airstream helps, Chris, but mice are sneaky and can work their way into an opening of perhaps ¾-inch diameter or smaller. Accessing tiny places is their gig, and they’re very good at it.

Barry, yes, we see letters about rodent intrusion all the time, regarding RVs of all price ranges, including the top-end models, but there’s not often anything new we can add to the discussion. An online search will reveal many different home remedies for trying to make an RV impervious to intrusions, as well as making the RV interior an undesirable place for mice to hang out.

Check a current RV, and you’ll probably see a fair amount of expanding foam at locations where pipes or wires enter the RV underbelly. It’s quick and easy at the factory to squirt in some foam and let it expand, harden and help seal up a gap. Check all those foam spots for signs of damage or chewing. You can buy aerosol cans of similar expanding foam at a home-supply or hardware store. When adding any spray foam, hold a small scrap of metal window screen in place to embed it in the foam to make it harder for mice to chew through later.

Pull the tires off your trailer and check all around inside the wheel wells. Those are places where gaps can easily exist and allow mice entry. Don’t forget the roof, as there are numerous vent openings, and some of those also provide direct access to the inner-roof structure or, from there, down inside the walls. A small piece of window screen, a piece of thin aluminum flashing, a caulking gun with latex- (not silicone) based adhesive and a pair of tin snips can go a long way toward sealing many mouse-access locations — although a determined critter may still chew through later.

A product that has been on the market for a few years called Mouse Free (www.mouse-free.com) is an undercoating and lubricant that can be sprayed on the undercarriage of the RV. Between the lubricant and the peppermint extract in the mixture, mice stay away, according to the company, and there are reviews online that confirm this.

These type of steps, along with any suitable hints you can find online, are about the best you can do to help mouse-proof your RV.


Waste-Tank Curiosities

Red letter Q
First, let me thank you for being there to answer so many questions over the years. Now for part one of my two-part question: When draining the tanks, regarding an electric macerator versus a standard traditional hose, is one better than the other?

Part two: My RV’s gray-water tank fills very quickly. Does it make sense to leave that valve permanently open while camping? I understand it’s good to use the gray water to flush the septic hose.

Dave Eisler | Oxford, Pennsylvania

Green letter AWe’re glad we can be of help, Dave. A macerator isn’t necessarily better than using a regular sewage-tank dump hose; it’s just a different way to do the job. Regular gravity dump hoses have worked fine for a long time, and they still do. A macerator provides several advantages, though, chief of which are its abilities to pump the waste a longer distance than is typically handled by an RV dump hose and to pump uphill if necessary.

You can use the built-in macerator hose, such as the one that comes with the Thetford Sani-Con system, or attach a minimum ¾-inch garden hose to the end of the macerator hose, which must be carefully kept separate from use for any other purpose. The garden hose would allow you to access a dump station at home, for example, where you may not have a standard RV sewage dump available.

If you always park in a place with a standard dump station, a standard hose will likely do the job. But if you want extra flexibility for more dumping options, and a cleaner and easier way to dump the tanks, a macerator is a good investment in hardware for your RV.

You can leave the gray-tank valve open, Dave, and then close it when you need the gray-water backup for flushing the dump hose after emptying the black tank. Personally, I’d leave the gray-tank valve closed all the time and open it only when the tank is mostly full.
When the valve is left open, water entering the tank and then flowing out of the hose is a relatively small stream of water with little velocity to carry away small-particulate solids that are present even in the gray water. With the tank partly or mostly full, there’s a lot more water pressure, volume and speed to carry away much of the particulates. This water flow can be especially useful when rinsing the dump house with the gray water after emptying the black tank. Also, when the valve is left open while connected to the sewer connection, sewer gas can percolate through the tank and back up into the RV and through the roof vents, which is quite unpleasant.

Open or closed, it’s your choice, but I know what I’d do.

Testing Safety Detectors

Red letter Q
I always check my smoke, carbon-monoxide and propane detectors before every trip. Recently, a good friend lost his fifth-wheel to fire while going down the road. No cause was found, but the trailer was a total loss. Since that incident, I checked my propane detector and pressed the button as always, and the alarm went off. I then checked the detector with an unlit propane torch, and it did not set off the detector. I purchased a replacement, and it worked perfectly and went off in the presence of propane. The old detector had a date that showed it was almost six years old. I hope this helps someone.

Russell Crawford | South Lake Tahoe, California

Green letter AThe various detectors in your RV don’t have unlimited life spans, as you discovered, Russell. The sensitive detecting elements are eventually contaminated by impurities in the air, such as cooking fumes, hair spray, aerosol cleaners or simple airborne dust particles and the like. A smoke detector may go eight years, an LP-gas detector, perhaps five years, and for a carbon-monoxide detector, about six years is a useful life span. Removing the detector may show a date code on the back.

If you buy a used RV and aren’t sure about its history, replace all of the detectors. These devices are not particularly expensive, and the safety they provide is always worth it.

Solar-Power Plug

Red letter Q
I have a couple of concerns, but the first is the main one. Last spring, I purchased a new Dutchmen Coleman trailer that had the Furrion solar-power port installed. I was excited about this because I use solar to keep the trailer’s battery charged when camping off the grid.

I had to order the connector to hook up the solar panels to the RV plug. But when I do that, it seems that the battery is actually drained of power rather than being charged. My dealer simply suggested that the panels are not “matched” to the plug. Maybe because this is something relatively new, the dealer knows nothing about it.

Furrion has not replied to my attempts to contact its customer-service people. I have fixed the problem by simply ignoring the plug and connecting wires from the panels directly to the battery, but there must be a solution that is better than this. It would be much easier to hook up directly.

My other concern is that the trailer has a power awning that is very rough while going out and retracting, as if something is binding up. The dealer replaced the channels and tracks attached to the RV, but this made no difference. Again, the dealer offered no further explanation or effort to fix the problem.

Sam L. Linkous | Blacksburg, Virginia

Green letter AFirst, you should not connect the solar panels directly to the battery, unless the solar-panel setup has an integral charge controller. The charge controller is a regulator that ensures the proper voltage is flowing to the battery. You didn’t say which brand of solar panel you’re using, but both the Furrion and Zamp Solar portable panels have built-in charge controllers. If you simply purchased one or more solar panels and put the system together yourself, then you likely need a charge controller.

It seems strange that the batteries are being discharged. Each solar panel has a blocking diode array to allow current flow toward the battery but not backward. Are you sure the solar panels are working correctly, and for that matter, wired with the correct polarity? Check their power output using a multimeter to determine that there is charge-level voltage in excess of 12.5 volts. For the best help with an RV-solar-charging setup, do an internet search for a local solar company that’s experienced with RV installations, and they can likely help get the setup straightened out.

It’s hard to speculate about an awning cure beyond what the dealer found when the trailer was in the shop. You didn’t say which brand of awning is on your RV, but contacting the manufacturer and inquiring about a local authorized dealer or service center might help. If they aim you at the previous dealer that installed new parts but didn’t cure the problem, have the manufacturer make a different recommendation so you don’t waste more money on a shotgun-parts approach to repair.

Often, it’s the small independent shops with mobile services and experienced help that can solve this kind of problem. In addition, if the awning was installed somewhat crooked, that can cause some extra binding and the jumping you notice. Finally, some of the motorized awnings don’t deploy smoothly at the best of times, so you may be seeing some standard operating procedures there.

Thermostat Replacement

Red letter Q
We bought our 2015 Keystone Bullet 248RKS travel trailer in the fall of 2015 and have enjoyed many trips in it. Every trip brings some kind of challenge and solution to the rig, including an upgrade of the water pump, a folding extension for the counter, awning protection while stored and so on.

The last trip out, I had to fumble with the thermostat at night, since it has no background light and is very hard to see without a flashlight. Is it OK to replace it with a comparable lighted home-type thermostat?

Chris Barkoukis | Washington Court House, Ohio

Green letter AIf your RV thermostat is the simple analog-type that’s nothing more than an on-off switch for the furnace, you can likely find a residential-type thermostat that offers the same connections, but most home thermostats operate more than just an on-off furnace circuit. The light in a home thermostat is powered by either a low-voltage supply routed through the wires leading to the thermostat, or internal batteries. Your setup may have just two wires available if it’s an on-off model.

So, you’ll need to route extra wires to the thermostat location, then find a suitable power supply for the unit, and it may not be 12 volts DC, so another option may be called for. If you need a transformer-type power supply, say to provide 24 volts AC to power the thermostat, then you probably won’t have the lighting available if you’re dry camped, if the thermostat will even work at all.

Many of today’s thermostats are designed with sophisticated circuitry that also operates the air-conditioning system and a heat pump, monitors exterior temperature, has timing circuits and so on. This applies to both home and RV HVAC systems, and adapting this type of thermostat cross platform would be highly impractical, if not impossible.

That said, if you have an analog thermostat that operates both the air conditioner and the heat, you may be able to upgrade the thermostat to one with more functions from the A/C manufacturer, but don’t try to connect someone else’s thermostat on the new units because damage to the control board can result.


Ken FreundRV DIYRV Tech

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