Todd is back to answer your RV questions, part 3

January 27, 2026

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Tony Flammia

Every Tech Tip Tuesday, we get a stack of questions from RV owners who are trying to do things the right way. Not shortcuts. Not guesses. Just solid answers so they don’t break something expensive—or put themselves in a bad spot down the road.

This week’s questions covered a wide range: water heater sanitation, window sealing, inverter sizing, and slide-out problems. Different systems, same goal—keeping your RV reliable and safe.

Let’s walk through them one at a time.

Will Bleach Damage an RV Water Heater?

Short answer: yes, it absolutely can.

Bleach is a hyper-saline chemical. When you mix salt, water, and exposed metal, corrosion isn’t a possibility—it’s a guarantee. How fast that damage happens depends on the type of water heater you have.

Some Dometic water heaters use aluminum tanks, which tolerate bleach better than others. Suburban water heaters are steel tanks, and while many are porcelain-lined, that lining can crack, fail, or wear over time. Once it does, bleach has direct access to bare metal.

That’s why we never recommend putting bleach into the water heater itself.

When sanitizing an RV fresh water system, the correct process is to bypass the water heater first. Sanitize the plumbing, then flush thoroughly. If you want to clean the water heater tank itself, vinegar is the right tool—not bleach. Vinegar dissolves mineral buildup without attacking the metal.

Bleach has its place in RV maintenance. The water heater just isn’t it.

Should RV Windows Be Sealed Along the Bottom?

This is a question that trips up a lot of new RV owners—and for good reason. You look at the window frame, see sealant on the sides, maybe the top, and nothing along the bottom. It looks unfinished. It looks wrong.

In many cases, it’s intentional.

Window design varies by manufacturer and window type. Frameless windows operate differently than framed windows. Inside the frame, there are often weep holes, which allow moisture that gets inside the frame to drain out. Sealing over those areas can trap water instead of keeping it out.

Behind the frame itself, you’ll usually find butyl tape providing the primary seal between the window and the RV wall. Exterior sealant is often there for secondary protection, not as the main barrier.

The best advice here isn’t a universal “seal it” or “don’t seal it.” It’s this:
Ask the manufacturer of your RV what their sealing specification is.

One brand may leave an area open for drainage on purpose, while another seals the full perimeter. Assuming they all work the same way is how people accidentally create leaks trying to prevent them.

Bigger Inverter Now… or Later?

Another viewer asked about installing a 5,000-watt inverter instead of a 3,000-watt, even though the RV currently doesn’t need that much power. The reasoning was future-proofing—and that’s smart thinking.

In general, when it comes to inverters, bigger is often better, because it’s usually a one-time purchase. The cost difference between a 3,000-watt and a 5,000-watt inverter is often surprisingly small.

That said, there’s an important catch.

You have to make sure the inverter fits not just your current RV, but your electrical architecture. Some inverters are single-leg 120-volt units. Others support split-phase power for 50-amp systems. Not all brands offer both options at higher wattages.

So the right question isn’t just “Should I go bigger?”
It’s “Will this inverter work with both my current RV and a future one?”

If it can, then stepping up in size makes sense. If it can’t, you may end up buying twice.

Slow Slide-Outs: When Voltage Lies to You

Slide-outs slowing down is one of those problems that feels electrical—and often is—but isn’t always obvious.

In this case, the owner had:

A new battery
Shore power connected
Proper voltage readings at the battery
Two different slides showing the same symptoms

That last detail matters.

When the same issue shows up in multiple systems, the problem usually isn’t the individual components—it’s what they have in common. That points to shared wiring, feed lines, grounds, or connections.

Loose or corroded wiring can restrict current flow even when voltage looks fine on a meter. The result is slow movement, stalling, or slides that won’t start without manual help.

At that point, troubleshooting becomes about tracing common feeds and looking for resistance—not guessing. And if that process isn’t something you’re comfortable doing safely, this is where a qualified mobile RV technician earns their keep.

Electrical problems don’t get better on their own. They just get harder to find.

Final Thoughts

None of these questions were exotic. None were rare failures. They’re everyday RV issues that become expensive when handled incorrectly.

The difference between a small fix and a big repair usually comes down to understanding why things are designed the way they are, not just how they look on the surface.

That’s what real RV training—and real experience—provides.

If you’ve got questions, keep them coming. These are the conversations that keep RV owners safer, smarter, and on the road longer.

And that’s this week’s tech tip.

Todd's back to answer your RV questions, part 3