Tuesday, November 28, 2023


RV’s water heater doesn’t get water hot on LP but does on 120 volts. Why?

Dear Dave,
My Suburban water heater (16 gallons) works, but when it uses propane, the hot water isn’t nearly as hot as it is when heated using 120 volts. Is there a way to increase the water temperature when using propane? Thank you in advance. —Terry, 2018 Arctic Fox 29-5T

Dear Terry,
I believe your water heater is a 10-gallon Suburban LP/120-volt, as all the information available online shows it came standard with the 10. Either way, it seems you have an issue with propane delivery to the burner which would cause a smaller flame and insufficient heating.

There is only one thermostat mounted to the side of the tank that monitors the temperature and turns the unit on when it gets below a certain point and off when it reaches temperature. This just registers the temperature of the water and doesn’t know if the unit is running on LP or 120-volt power through the heating element. Typically, the temperature is set at a limit of 130 degrees and starts back up at a 100-degree temperature. You can see this by opening the outside access door. You should see the T/Stat and ECO.

The first thing I would do is clean out the supply tube and burner assembly. In the photo above, the gas valve is to the left with the silver tube coming out the bottom. The copper tube is the supply line which has an opening at the beginning that mixes air with the LP. Use an air compressor and blow gun to thoroughly clean the opening and the tube all the way up to the spark ignitor. There can be dust, soot, and even a spider web that can restrict flow and that’s why your RV’s water heater doesn’t get water hot.

Another possible reason why RV’s water heater doesn’t get water hot on LP

If that does not help, you need to check your regulator and supply lines. You can do a quick test by turning on a stovetop burner and verify the flame is a consistent blue and not jumping around or has an orange flame. Then turn on the second burner and see if it affects the flame with more demand, and then the third.

Make sure you have the stove vent running to disperse the heat. With all of them running, start your water heater on LP and see if the regulator can keep up with the demand. It may be weak. When the refrigerator cycles, it could be depleting the LP to the water heater and a light flame.

Recently we had an issue with a refrigerator running on LP but it was good on 120-volt power. The culprit was either a dirty supply line or moisture in it. My Dometic technician recommended having a qualified technician clean out the lines to the refrigerator, as this is very seldom recognized. It fixed the situation. This might be something your rig needs.

 You might also enjoy this from Dave 

My Suburban water heater doesn’t work on 120-volt power. Does it need a second switch?

Dear Dave,
My Suburban water heater doesn’t work on shore power, or any other 120 power source. I made sure the switch was on at the water heater. I also verified I had power at the outlet that the water heater is plugged into and that it was actually plugged in. The only obvious thing I see is that there is no switch for the water heater to run off of 120 on my control panel. The only switch is for gas operation. Do I need the second switch? I looked on the Forest River website, but it’s of no help, and the dealer is backed up for months. Can you help?? —Kevin, 2021 East to West Della Terra 271BH

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Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

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Dave Solberg
Dave Solberghttp://www.rv-seminars.com/
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.



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Bill Byerly (@guest_242817)
4 months ago

More useful information, thanks Dave!

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