Mud Daubers In Your Vents?

A friend of ours was having a fluky sort of problem: His RV furnace wasn't quite up to par; didn't want to light, made some odd noises--the last of the odd noises more like a cannon shot. Kaboom! After ascertaining that various muscles in his body hadn't failed him at a critical and embarrassing time, he hustled out doors from whence the noise had come. Sure enough, on the ground around his furnace vent, the tell-tale remains of a mud-dauber nest. The poor creature had built her nest and lain precious eggs in Joe's furnace vent, only to be swiftly evicted.

First, 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, 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's 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.

Battle of the Ants

The popular children's song, The Ants Go Marching, begins a progression of a single ant marching through ten rather tedious verses, finally ending with the ants marching 10 by 10, and the little one proclaiming this is, "The End!"

Sadly, ants in the RV never go marching singly, and rarely by the 10s. We woke up one fine morning with an upset cat, doing her best imitation of a bird dog 'at point.' Her hissing target? A large, black, moving column of ants, working its way across the RV from a crack near the entry door, across the flooring, up the wall cabinet, and into the kitchen sink. Hundreds of the little boogers, all intent on carrying away whatever it is that struck their fancy.

Ants in the RV, like the proverbial ants in the pants, are nothing to laugh about. How do you get rid of them, and keep them gone? In our case, the first response to the attack (after cat and distaff set cleared the area) was a trip to the local hardware store. A high powered spray specifically designed for invading ants made fairly quick work of the invading forces. But how to keep them gone? Friends who were serving as Katrina relief volunteers in New Orleans quickly filled us in on the 'magic circle of Comet' trick used down there.

Ants are clever creatures--they send out scouts who scurry about the territory, looking for suitable food and water sources. If one crawls up your RV tire, water hose, power cable, et al, and eventually finds something inside your rig, he or she leaves a little smell trail of pheromones. Your proboscis won't pick up on it, but to the ants, it's an irresistible essence that must be followed--by hundreds of the scout's fellows. Why are these ants marching in a circle? Clever researchers took a dilute form of their pheromone and painted on the paper, then turned the ants loose. It's strong stuff--it's said that as little as .33 of a milligram of straight pheromone could leave a discernable trail around the entire circle of the earth!

For whatever reason, ants won't cross a line of bleach-containing scouring powder. Maybe it kills the pheromone trail, maybe it burns their little feet, we don't know. In any event, get out the Comet and shake a good border around everything of your rig that touches the ground: Tires, landing gear, stabilizers, cords, and hoses. This is better than spraying insecticide on these utilities, because the powdered cleanser will simply shake off, not stick to your hands, nor cause grief for pets and kids. Of course, if the rains fall you may need to renew your magic circle, but while the powder's out, the ants are gone.

Photos courtesy US Department of Agriculture

Spring Cleaning Time for Fresh Water Tanks

If your RV has been sitting "in the mothballs" all winter and you're readying it for travel season, don't neglect the fresh water tank. It only takes about one mouth of "yecchh!" water to convince you that water can go stale. What's to do? Well, this is the same trick we recommend when you buy an RV prior to using it.

You'll need to completely drain your fresh water holding tank, and run the water pump until all water is out of the system. If your water heater is "in the circuit" (meaning not winterized, but holding water) drain it too, using the drain cock on the heater. Of course, you've shut it off first.

Determine the fresh water tank's capacity--easy if you have the rig's owner manual. If not, locate the fresh water tank and measure it. Break down the feet and inches to decimals, i.e., a 4' 6" run is 4.5' Multiply the height, width, and depth figures to come up with total cubic feet of capacity. Now multiply the capacity times 7.48051945, which is the conversion factor for cubic feet to gallons.

With gallon capacity on hand, drag out the household bleach--NOT the scented variety. In a clean container, a one gallon cleaned juice jug is ideal, pour 1/4 cup of bleach for every 15 gallons of tank capacity. Top off the jug with clean, fresh water. We had a careful reader warn us to only add bleach to water--we've got a call into a bleach manufacturer for clarification. If you're concerned, pour "guestimate" how much room you'll need in the jug for the bleach and put the water in first. We'll post our research results as soon as they become available on the "bleach last" issue.

Be sure your fresh water drain valve is closed (and the water heater if applicable, and pour this bleach solution into the holding tank. Now completely fill the fresh water holding tank with clean, fresh water. At this point if you can, move your RV around the block to thoroughly swish and mix the solution in the tank.

Now turn on the water pump and pump the bleach solution through all the plumbing. You'll know when you've pumped enough as you should smell the bleach solution at the fixture. Let solution stand in the plumbing and fresh water tank overnight. Next day, drain the fresh water tank (and again, water heater if applicable), and refill the fresh tank with clean, fresh water. If you're concerned about the chlorine taste or odor, mix up a solution of 1 quart of cider vinegar for every five gallons of tank capacity and dump it in the fresh tank, repeating the same process you did for the bleach job.

Air Conditioner Maintenance Part 2: Up on the Roof

In our last installment we discussed how to handle the "inside the rig" part of air conditioner maintenance. Now we move to the part of the job will take you up topside. You’ll need a sturdy ladder. As a general rule to protect your roof, don’t walk on it. This particularly applies to older rigs that don’t have a solid plywood deck under the roofing material. Best to put a "kneeler board" across the rafters and knee walk across it to reach the ac unit.

At the unit, check out the condition of the condenser fins. These little guys provide a broad surface for outside air to draw away the heat pumped out from the inside of your rig. If they’re bent, like the two photos show, they’ll need to be straightened out to remove that heat efficiently. A thin knife or screwdriver blade may help. Or you can use an air conditioner fin comb--a specialty tool that can help if the fins are not too badly bent. We once spent countless hours with a knife blade straightening out a whole mess of fins that had been completely bent over.

While on the roof, inspect the ac unit "shroud," the protective cover. These are prone to taking hits from branches; plastic ones often get damaged by UV rays. Sometimes they can be fixed with fiberglass cloth and resin--check out a boat supply or auto parts house. If you repair cracks on the inside of the shroud, the work will likely be secure, but not obvious to outside observers. A more expensive solution is installing a replacement shroud.

The shroud should be securely mounted, you’ll find screws around the bottom of the shroud that tie it to the ac unit itself. Too much zeal with a screwdriver can easily crack the shroud around the mounting holes, rendering it useless. Take it easy! Firm, but not over-torqued is the rule for installing a shroud.

Take the screws out and carefully remove the shroud. Again, make sure you have the power disconnected--you don’t want the ac unit to start up while you’re poking around "under the hood." You’ll be looking for the evaporator--it looks like a small automotive radiator. Take a brush and gently remove dust from it--if you have an air compressor, gently blast the dust out with pressurized air. Getting the dust out will make your system more efficient.

Now check out the motor. Some ac units will have oil holes, possibly covered with a rubber plug. Other ac motors are permanently sealed and don’t require lubrication. For the former, carefully remove the plug and add 3 or 4 drops of oil--some recommend "three in one" oil for the job. Over-oiling is worse than not oiling! Replace the rubber plug(s).

Put the shroud back on, while keeping the torque down to a dull roar.

Wind It Up

Now it’s time to test the system. Be sure you have sufficient power--most ac units require your RV be hooked up to at least a 30 amp service. If you don’t have the power, wait until you get somewhere where a 30 amp circuit is available. Turn on the unit and let her rip. You should have plenty of cold air delivery. Enjoy a cool summer!

RV Air Conditioner Maintenance Part 1: The Inside Job

As summer draws closer (or for those of us in the southwest, as it continues on unabated), air conditioning becomes more of a critical issue. Here begins a two-part piece on the hands-on of air conditioner maintenance. We’ll address the most common of RV air conditioning systems--the roof mounted ac unit. Exposed as it is to the elements and low-hanging branches, the roof mounted unit is prey to a lot of problems. But let’s start "inside" first.

The easiest part of the assignment is simply cleaning or replacing air filters. Check your owner’s manual to find instructions for getting the filter out of the unit--typically by removing a couple of screws and pulling a grill loose to access the filter. This filter, although cleaned in the last few weeks, is in serious need of cleaning again.


Some ac unit filters can simply be washed in warm, soapy dishwater, thoroughly dried, and reinstalled. In use, washable filters should be removed and cleaned a couple of times a month if used in dusty areas; once a season should be enough elsewhere.

Some ac filters are not washable but must be replaced. Here’s a thought: You can replace nearly any ac filter with an after-market "electrostatic" filter that is said to capture more dust and pollen than typical OEM filters. We’ve never actually tested them out, but if you’ve got twenty bucks to check the theory out, visit a Camping World store for these super filters.

While you’re working with the filter, check out your unit’s ducting. Some rigs have simple metal channels to deliver chilled air; others may use heat distribution hoses. If you can, it’s a good time to vacuum out your ducts while servicing the filter.

So much for filters, if you’re feeling a bit more adventurous, check out unit security. We’re not talking about somebody stealing your ac unit, but rather having the thing get loose and fall of your rig. An ac unit is bolted onto your rig roof top, and generally speaking, the mounting bolts come down through the roof and snug up inside the rig. Often these can be accessed by removing the inside trim that surrounds the unit. Be sure to disconnect the power before puling this trim--you may expose electrical fittings you don’t want to get your fingers into. Once you spot the mounting hardware, make sure it’s tight. Incidentally, water leaking into your RV through the ac unit can sometimes be traced to loose mounting bolts.

We'll get onto the outside work in our next installment.