How To Tell If Your RV Tank Heaters Are Working
Updated: Apr 14
Tank heaters are among the more minor features of your RV. But that doesn’t mean they don’t work hard to protect the condition of your vehicle and its plumbing. In fact, if you’re traveling through freezing temperatures, tank heaters are one of the only things standing in the way of severe damage to your RV’s underside and water systems.
That’s why it’s essential to understand if your tank heaters are still working or if it might be time for repairs or replacement. Learn more about how these features work so you’ll know when it’s time to make adjustments.
What Are Tank Heaters and What Do They Do?
Before we get too deep into how to tell if your RV tank heaters are working, it’s best to review what they are and how they work. In essence, RV tank heaters are simple heating devices that fit on the underbelly of your RV’s water and wastewater tanks. They’re usually electric and get power from your vehicle’s battery or converter when plugged in. Typically, you can switch tank heaters on from inside of your RV.
From there, they heat up and keep the temperature in your holding tanks above freezing. These heaters are incredibly valuable to any RV owner. But they’re especially helpful for those who enjoy traveling through frigid winter weather. The entire purpose of tank heaters is to ensure that your tanks are well-protected from the cold.
They also exist to ensure you have access to a fully functional plumbing system and clean water, regardless of outside temperatures. Specifically, they prevent RV tanks from freezing over and sustaining damage from cracking, blockages, and other issues that could be detrimental to your direct plumbing systems. In addition to tank heaters, pipe and elbow heaters keep the pipes surrounding your tanks warm, which keeps lines from bursting and causing severe damage.
How Do I Know If They’re Working?
Like any other vehicle part, tank heaters will eventually outlive their usefulness. When they do, you must know what to look for. There are a couple of ways to figure out if your tank heaters aren’t working correctly. But the best option is to use a watt or amp meter to test for the current draw your tank heaters are producing.
This strategy starts with switching on your tank heaters and leaving them overnight. It’s important to do this on an evening when freezing or below-freezing temperatures are expected. That way, you get a complete picture of how well your heaters can warm your plumbing systems. The following day, you’ll measure the current that each tank is giving off and see if it matches the standard. Note: tank heaters have a built-in sensor that monitors the liquid temperature inside the tank. They are designed to power “on” at 44F and “off” at 64F. If needed, you can always place a block of dry ice or a bag of crushed ice on the sensor to fool it into thinking it’s cold enough to be activated.
Your tank heaters will have a standard level of current they should be exuding. If it’s within the proper current bracket, then it’s safe to assume your heater is working correctly. On the other hand, you may find that your measurements are far below or above the ideal current. If so, it might be time to examine further and see about having them repaired or replaced.
When Should I Replace Them?
It’s not enough to know how to tell if your RV tank heaters are working. You also need to understand when it might be time to get new ones. Of course, this can be challenging if you’re unaware of what to look for.
And understanding that they’re not giving off adequate current or heat levels isn’t enough to glean if replacement is necessary. Sometimes, all that’s needed to get them heating again is a quick adjustment or minor repair. Luckily, a few defining factors indicate a replacement is inevitable.
#1. Loose Adhesive
As we know, tank heaters are devices that stick to the underbelly of your RV. To stay in place, they must be installed with a strong adhesive. Thus, loose adhesive is one of the first signs that your heaters are due for a replacement. So, when you go to inspect the condition of your tank heaters, look carefully for any signs that they might be starting to lose their grip.
If you notice that they’re flopping down in the middle or on the sides, it’s a good indicator that they’ll need replacing or—at the very least—reinstallation. Taping them down is an excellent way to fix them temporarily if you’re on the road. Just remember to make time for a more permanent solution as soon as it’s convenient.
#2. Damaged Wiring
Loose adhesive is one thing, but damaged wiring on your tank heaters is another issue altogether. To that end, it’s a more severe one that you must take care of immediately. You see, tank heaters are electrical devices that draw power from your RV’s 12 volt electrical system. Their wiring systems are what enable this capability. They could not do this if their wiring systems sustained any considerable damage.
Thus, if you suspect your tank heaters are no longer working at total capacity, checking their wiring is a good way to gauge whether you need to replace them. Perhaps you’re camping in below-freezing temperatures. You go to the bathroom and realize that there’s something off about the way your toilet flushes or that it doesn’t flush at all. You go outside to examine your black tank heater and notice that its wiring is worn, exposed, and detrimentally frayed.
In this case, it’s safe to assume that this tank heater needs to be replaced. This is simply because it is no longer capable of drawing the power it needs to keep your black tank warm and blockage-free. And the same rules apply to any of your water and wastewater tanks.
#3. Failure To Heat Your Tanks
Of course, the most obvious sign that your tank heaters are due for replacement is when they completely fail to get warm. This is certainly easy to test for. You don’t necessarily have to measure the currents of your heaters or double-check any specific components.
Instead, you’ll be looking for whether or not they’re giving off any heat at all. Switch your heaters on and see if they start warming up. If there’s no difference in temperature once they’re on, it’s time for a replacement.
How Do I Keep Them in Great Shape?
With all that being said, if you take proper care of your tank heaters, you likely won’t have to worry about replacing them for a long while. And fortunately, keeping these essential features in excellent shape isn’t tricky. All you need to do is regularly clean and investigate them for issues.
Doing so ensures that you catch minor problems early. It’s also a good idea to flip them on only when your tanks start to dip in temperature or when you’re anticipating frigid, potentially damaging weather. This prevents unnecessary wear and damage to your tanks.