Repair
When 'No Hot Water' Isn't the Water Heater's Fault
By Brad Tomlin · June 17, 2026
Picture this: you've hooked up at a campground, ready to rinse off after a long day of travel, and the faucet runs stone cold no matter how long you let it flow. That's exactly the complaint we got on a 2017 Hartland Mallard travel trailer. No hot water at any faucet.
Diagnosing the 2017 Hartland Mallard's Hot Water Problem
Our first instinct with a "no hot water" complaint is never to assume the water heater itself is bad. Plenty of owners jump straight to that conclusion and start pricing out a replacement unit, but that's often the wrong move. In this case, once we got hands on the system, the issue turned out to be a lot simpler (and a lot cheaper to fix) than a failed water heater.
The bypass valves were closed. On most travel trailers, including this Mallard, the water heater bypass system exists so you can winterize the trailer without pumping expensive RV antifreeze through a six or ten gallon tank. Flip the valves to bypass mode, and water skips the tank entirely, running straight through the plumbing instead. It's a smart design. But if those valves get left in bypass position after de-winterizing, or somebody isn't sure which way they're supposed to sit, the water heater tank never fills. No water in the tank means no water gets heated, no matter how good the heating element or gas burner is.
Why This One's Easy to Miss
Here's the thing about bypass valves: they're usually tucked behind an access panel or inside a cabinet, out of sight and out of mind. Most owners don't even know they exist until something goes wrong. And when the symptom is "no hot water," it's natural to assume the worst, a dead heating element, a cracked tank, a bad thermostat. Chasing that assumption can cost real time and money if nobody stops to check the simple stuff first.
That's the value of our Readiness Walk-Through, having a trained eye look at the whole rig before you leave. We are trained to RVTAA technicians, which means working through a system logically from the source of the water flow outward, rather than guessing at the most expensive possible cause. In this case, the correction was straightforward: open the bypass valves, let the tank fill, and confirm hot water at every faucet before calling the job done.
A Simple Fix, A Real Difference
Within a few minutes, the Mallard had hot water running at every tap again, ready for whatever camping trip was next on the calendar, whether that's a weekend trip or a longer road trip. It's a good reminder that not every plumbing complaint means a new water heater. Sometimes it just means somebody needs to know where to look.