Frustrated with a frigid RV furnace, our friend Joe tried everything he could. The thing refused to light and made odd noises. He’d switch it off, wait, and try to relight it. The final relight cycle was the culmination. A hearty “Kaboom!” retorted like a cannon shot. After ascertaining that certain muscles in his body hadn’t failed him at a critical and embarrassing time, he hustled outdoors from whence the noise had come. Sure enough, on the ground around his furnace vent, the telltale remains of a mud-dauber nest. The poor creature had built her nest and laid a precious egg in Joe’s furnace vent, only to be swiftly evicted.
A word about mud daubers: these solitary wasps gather mud, roll it into balls, and form small dirt nests. Into these small but cleverly constructed cells, a stung (and thoroughly stunned) insect is placed, along with a solitary egg. Mama mud dauber flies away, secure in her buggy knowledge that “junior” will have something to eat when hatched.
While this tear-jerking story from nature may cause some to reach for the tissues, the rest of us swear and curse the day that Mama found our RV. The common reaction—head off to RV MegaPart and pick up a set of mud dauber screens, described as “an essential companion to your RV furnace.” Hold onto your bee-veils, fellow wasp warriors—“essential” ain’t necessarily so.
RV furnaces and water heaters, like us, are air breathers. And like us, stick a little something extra over our nose (or vent) and you get what? A bit of an obstruction that can cause problems, particularly for RV appliances. Systems can operate in strange ways when not enough precious pneuma is available, and some RV technicians warn that obstructed “windage” can actually lead to premature appliance death. If you’ve priced out furnaces lately, you’ll want yours to last a long time. Sticking on one of those so-called “essential” screens can actually cause more harm than good.
What to do? When not using the rig, TAPE over the vent, and post a note over the furnace thermostat or water heater switch warning the user to remove the tape before firing up the appliance. When in use, make checking out appliance vents a regular part of your walk-around routine. Worried about getting stung? If you spot a wasp nest, take a stick and remove it at night. We don’t recommend shooting the nest with wasp killer—can you imagine what might happen if your wasp spray turned out to be flammable and your furnace “lit off” when you sallied forth with your can of Bug Off! Ah, the picture it presents.
And one more thing: For some peculiar reason, it seems mud daubers are attracted to the scent of propane. On “light off” a bit of that odor is released, and that may be just enough to attract these little devils. Furnaces aren’t the only RV appliances that can become attractive. Water heaters and refrigerators also emit the attractive odor. One reader told us they had a siege of propane alarm signals driving them nuts. They took their rig to a technician who knew just where to look—in the refrigerator flue. Make sure your refrigerator roof vent screen is intact. And do periodic inspections of all your gas appliances!
Russ and Tiña De Maris are authors of RV Boondocking Basics—A Guide to Living Without Hookups, which covers a full range of dry camping topics. Visit icanrv.com for more information.