Moving Forward
Dear RV Doctor:
I recently purchased a 2003 motorhome. I have emptied the black water holding tank and noticed we still get a bad odor when driving. I do not notice the odor when the unit is parked. Do you have any suggestions on how to correct this problem?
Elaine Horton, Elk Grove, California
The first thing you should do is fully flush out the holding tanks with copious amounts of fresh water. Keeping them rinsed after each evacuation will help minimize holding tank odors. You state that the tank was evacuated but do not mention whether you’re adding fresh water afterward. Also, if you’re not yet doing so, add only enzyme-based tank additives to help break up the solids in the black water holding tank.
Probably the best thing you can do to eliminate odor when traveling is to replace the existing sewer vents on the roof with a product such as Xtreme Vents, available from Coil n’ Wrap (www.coilnwrap.com). These aerodynamically designed roof vents capture the breeze when the RV is standing still and take in ram air while it is being driven. Xtreme Vents operate on the Venturi principle of air being passed over a tube. As air passes over the open end of the vent pipe, it draws air and odors from the tank. This will help eliminate odors by literally “sucking” them out of the tank. This is extremely helpful, especially when a 14-inch roof vent is located very close to the sewer vent. The Xtreme Vent should eliminate issues caused by this design that shows up on some floor plans. And remember, there are just as many odors emanating from the gray water holding tank as the black tank. I consider this vent one of the best add-on components available.
Not Moving
Dear RV Doctor:
My wife and I are new to the RVing world. We are excited about it but a little apprehensive. We have many questions, many of which we don’t even know to ask yet! One question we do have is about the holding tanks. If we camp only one or two weekends a month for a couple of days each time, do we need to wait until the black and gray tanks are at least three-quarters full before we dump? That might mean our coach would sit in storage for maybe two to three weeks at a time with waste in the tanks. Is that okay? Another question concerns the fresh water tank. Would I drain both this tank and the hot water heater after each weekend trip if the RV just sits there?
Roger Elsbury, Topeka, Kansas
You should avoid leaving waste in the tanks during the weeks between trips. If you’re using the RV only on the weekends, I recommend dumping the tank after each weekend trip. If your tank is not up to the recommended dumping level, simply add fresh water so that the total capacity of the black holding tank is more than three-quarters full before evacuating.
Here’s why. In order to maximize the flushing velocity, it’s necessary to have the tank filled or almost full. A partially filled black tank can lead to tank blockages if there is not enough force to flush out all the contents. This isn’t normally a concern when emptying the gray tank. Just evacuate it normally after emptying the black tank. And be sure to run fresh water through the toilet after draining the tanks to rinse the sewer hose, the valves, and the connections.
The polyethylene fresh water tank and the water heater should not suffer any ill effects during storage periods of less than a month if you choose to leave them filled. But you have to be the judge. If the water smells funny or tastes stale, then you may have to drain and refill the tanks after each use. As you are probably aware, much depends on the quality of water you put in there to begin with. Many motorhome owners prefer to dump all the tanks, including the fresh water tank, to avoid the added weight while driving.
A Better Battery
Dear RV Doctor:
I think my coach batteries may need to be replaced within the year. I asked my RV dealer whether AGM batteries are a good idea. My motorhome currently has the older flooded-cell-type batteries that came from the factory (two chassis batteries and three house batteries). The answer I got from my dealer was to stick with the technology it came with and not switch to AGM batteries. I have a 2004 Itasca with a three-stage charger. I’d be interested in your comments and advice. Also, I used to enjoy your TV show. Is it still on?
Jon Davison, F389309, Lakeville, Minnesota
I’m guessing your dealer does not sell absorbed glass mat (AGM) batteries but does sell flooded wet-cell batteries. My advice? Well, I’m a strong proponent of the AGM technology. And since today’s motorhomes are so DC-voltage dependent, I’m also in favor of having as much DC current onboard as possible. Following are some arguments for switching to AGM batteries.
First, they are highly resistant to vibration and shock, which is a plus for RV applications when you consider the jostling and bouncing the motorhome does on the road. Their recombinant gases are effective to about 99 percent. What this means is that the hydrogen and oxygen are recombined inside the battery safely within each cell. Have you ever noticed the bubbling and off-gassing of a lead-acid battery while under a charge? Most AGM batteries vent hydrogen vapors at less than 2 percent, where 4.1 percent hydrogen vapor is needed to support flammability in the air.
The inherently low internal resistance of an AGM battery is another welcomed benefit to RVers who store their motorhomes part of the year. According to one maker, during storage, the self-discharge rate of an AGM battery is three to 10 times less than a gel battery and almost 50 times less than a typical flooded lead-acid battery. The reason is because the electrolyte is not liquefied, but rather absorbed into the floss-like glass matting.
AGM batteries also deliver and receive current much faster and at the higher rates available today. Your three-stage charger will suffice nicely and adapt well for AGM batteries. As an example, AGM batteries can be charged 10 times faster than a same-rated gel battery and five times as fast as a like-sized flooded lead-acid battery. Because AGM battery technology permits more positive plate material to be saturated by the absorbed mats in each cell, there is an automatic increase in the battery’s capacity in virtually every area.
More life cycles, reduced internal resistances, higher amp-hour rating, more reserve capacity, and greater depth of discharge cycles are some of the improvements when compared to other types of sealed lead-acid batteries.
As you can see, I do like AGM batteries. So, in my opinion, if your wallet can endure the outlay and you consider yourself a serious RVer, then you should consider the upgrade when it’s time to replace your existing batteries.
Thanks for the comments regarding the television show. Currently we are ready to go with a brand-new show, but we are awaiting sponsorships from manufacturers and campgrounds. Unfortunately, it may be a long wait, given the state of the industry right now. But we are set to go as soon as the advertising dollars can be raised. It wouldn’t surprise me if the DIY Network puts the 13 episodes of “RV Roadtrips” into rerun circulation some time in the future.
Pondering Plastic Piping
Dear RV Doctor:
Why aren’t standard, cement-together plastic pipe and fittings used in the repair of RVs when replacing factory-installed fittings?
Clyde Harrison, Billerica, Massachusetts
Since you asked about pipe and fittings, I’m assuming you are referring to the RV waste piping systems. Standard ABS plastic fittings are indeed still used in the repair of RV drainage systems. Most every RV contains Schedule-40 ABS plastic pipe for all “P” traps and drains as well as vent stacks. Some components, such as the termination valves, are bolted (using adapters) rather than cemented, but the majority of RV manufacturers still use cemented fittings for simple connections such as elbows, “T”s, and “Y”s, in both the black and gray waste systems.
Now, if you meant cemented fittings for the distribution of the fresh water, the norm today is cross-linked polyethylene (PEX) tubing. It used to be the gray polybutylene tubing and, before that, cemented PVC and CPVC pipe and fittings and copper tubing. PEX is much easier to install, less expensive, and lighter in weight than copper tubing, which you still may see periodically in some custom installations. A few different connection methods are used with PEX fittings, including a variety of clamps and rings, but none involve glue or cement. The fresh plumbing systems in RVs today have the advantages of flexible tubing rather than rigid piping for the distribution of fresh water. But the waste systems still employ cemented ABS pipe and fittings.
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