Nearly all RV water heaters operate on LP gas; there are rare exceptions. But some RVs offer an option on their water heater: an electric heating element. How do you know if you have the optional electric element? If you do, how can you get the most advantage from either fuel option?
DSI versus “standing pilot”
Probably the most common ignition system for RV water heaters is called DSI, for “direct spark ignition.” It’s pretty convenient: Push a button inside your RV and your water heater lights up. We remember our early rigs, ones equipped not with DSI but with a “standing pilot.” When you wanted to use the water heater, somebody would get to go outside, open a cover, manually light a small pilot flame, make sure it stayed lit, turn some controls, and head back inside. The water heater was “on” all the time, burning up propane, until manually turned off—outside again.
A DSI switch is usually combined on a control panel that also controls the water pump, and may show holding tank levels. Most often found in the galley area, look your control panel over. In the photo above, you’ll see a control panel that includes the switch for “LP GAS”. To the right of the gas switch you’ll see one labeled “ELECTRIC”. This owner has a DSI gas water heater with the optional electric element. In the market? Here’s one on Amazon.
Make sure there’s water in that heater!
Switching on the gas side of the water heater is easy. Of course, make sure you have water in the heater. Many RVs are equipped with a “winterization” system that cuts the water heater out of the water supply. If your winterization bypass system is set to “winterize” and the water heater is empty, turning it on could lead to serious damage. The bypass system may still allow water to flow out of the hot water taps, but not allow water into the water heater.
If you don’t understand your bypass system, the only way to verify that your water heater has water in it (and is safe to “fire up”) is to do this: Go outside, open the water heater access door, and pull the handle on the pressure valve to ensure water flows out. Stand to the side so as not to get splashed. Let the valve handle loose when you see water flow out—it’ll snap back closed.
Turning it on
Now that you’re certain your water heater is full of water, you can turn the gas part of the heater on. Flip the control switch, and you’ll likely hear a “woosh” when the gas burner on the heater lights up. If there is a problem, the water heater will attempt to relight a set number of times. If it can’t light, for example if you’re out of propane gas, then an indicator light will turn on. You’ll see this indicator in the photo to the right of the LP gas switch. It’s labeled “DSI FLT”—indicating a fault in the direct spark ignition system.
Turning on the electric side is also easy. Generally you’ll find the switch for the electric element on the same control panel as that for the DSI. In some cases, an after-market electric element might have been added, and likely, no switch inside. If that’s the case, you’ll have to go outside, open the water heater access panel, and look for a switch to turn on the electric element, if there is one.
Gas or electric—Which is best?
So, what’s best to operate your water heater on—gas or electric? In terms of cost, gas is generally less expensive than electric, often several times less expensive. If electricity is included in an RV park rental bill, and not an added fee, many RVers will immediately choose electric operation.
There are a couple of other considerations, however. If your RV electrical service is 30-amp (three metal connectors on your electric cord where it plugs into the park pedestal), you’ll probably NOT be able to operate your water heater on electricity and use air conditioning, or the microwave oven, at the same time. Try and do it, you’ll trip an electric breaker. If your rig has 50-amp service (four metal connectors on your electric cord), then you’ll likely be able to operate your water heater and other “big electric users” on electricity at the same time. Using an adapter to plug a 30-amp RV into a 50-amp connection WILL NOT solve this problem.
Keep in mind, it generally takes longer to heat up water using the electrical element than by using LP gas. However, if you’re in a pinch and need hot water in a hurry, you can safely turn on both the gas and the electric element on your water heater at the same time.
Hot water safety
Speaking of hot water, you’ve likely been spoiled by having an adjustable thermostat on your water heater at home. Most RV water heaters are equipped with a fixed, non-adjustable thermostat. The fairer writer of this article finds ours to be “too hot.” So use caution when you may come into “skin contact” with the hot water in your rig. Be safe, and enjoy your RV lifestyle!
Tune in next week for more “Know Your RV” tips. And if there’s something about your RV that you’d like to know, drop us a line. Use the form below, and insert “Know Your RV” on the subject line.