Electric water heater noise -- hisses. Stops when switched off.

dan00500

Member
What does it mean when the electric water heater hisses? I have been RVing for about six months (three in my driveway, three on the road).

The noise is coming from the area of my pass-through where the water heater is located. And, when I turn the water heater (switch) off, the hissing stops. We rarely use LP for heating water, and in this case that switch is completely off. So, I'm pretty certain it's limited to the electrical side of the water heater.

I am not adept at RV water heaters, so you can school me here--even with remedial suggestions.
 

JohnDar

Prolifically Gabby Member
Check the pressure relief valve when it hisses. It may be partially open or leaking.


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Lou_and_Bette

Well-known member
Relief valve may leak/?hiss if you have lost the air bubble (air cushion) in your hot water tank. Check in the tools section for ways to fix this.
 

JWalker

Northeast Region Director-Retired
We had a similar issue in our last fifth wheel. When I was sitting on the couch and it was quiet, I could hear a hissing/sizzling sound coming from our hot water tank. When I shut off the electric portion, the hissing stopped. Removed the electric heating element and found a calcium buildup of some sort coating the element. I must’ve got into some rough water somewhere. Replaced the element and all has been well.
 

SLO

Well-known member
Relief valve may leak/?hiss if you have lost the air bubble (air cushion) in your hot water tank. Check in the tools section for ways to fix this.

Confused. What air bubble in water heater? hoefler is right. Water in contact with super hot element sizzles.


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SLO

Well-known member
Check out page 8 of our Water Heater Usage Guide in this folder.

Thanks for the link and I read page 8. Still, unless RV water heaters are a lot different than residential water heaters, there is no air gap in water heaters. Is this info from the manufacturer?


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danemayer

Well-known member
Thanks for the link and I read page 8. Still, unless RV water heaters are a lot different than residential water heaters, there is no air gap in water heaters. Is this info from the manufacturer?


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Here's a link to the various water heater manufacturer manuals. I know Suburban speaks to the air pocket. Not sure about Atwood.
 

dan00500

Member
Thanks everyone. So far, I'm tracking three things that it could be...

1. Cold water that's being heated. This certainly makes sense, because our water kettle makes the same sort of noise when we turn it on for coffee in the mornings.
2. Calcium covered heating element. I'm not sure how to get to the heating element on the water heater, but I need to learn more about my rig. Anyone know which manual I'm supposed to be reading about this? I do not know which one of the manuals is relevant to me from within the pile of them in the Tools section.
3. Missing air pocket at the top of the heater tank. If the pocket goes away because of a leak, I must have missing leak too. There's no evidence of a leak that I could see when I was looking at the water heater compartment inside the pass-through.

Thanks.
**Dan
 

carl.swoyer

Well-known member
What does it mean when the electric water heater hisses? I have been RVing for about six months (three in my driveway, three on the road).

The noise is coming from the area of my pass-through where the water heater is located. And, when I turn the water heater (switch) off, the hissing stops. We rarely use LP for heating water, and in this case that switch is completely off. So, I'm pretty certain it's limited to the electrical side of the water heater.

I am not adept at RV water heaters, so you can school me here--even with remedial suggestions.
Have you looked at the back side of the water heater? I'm wondering if you have a leak.
My 2012 had a unrepairable leak on the jacket.

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danemayer

Well-known member
The water heater has an exterior cover that's easily removed. Under that cover you'll find a plate that identifies manufacturer and model. That will get you to the right manufacturer's manual.

If you have a Suburban water heater, there's a procedure for removing the electric heating element starting on page 9 of our Water Heater Troubleshooting Guide.

If you have an Atwood water heater, the electric heating element may be more difficult to get to. You might need to get service help if you want the element inspected.
 

Todster

Active Member
I also hear a high pitched tone when the hot water heater is operating on electric only. Specifically when the heater is actually heating. Once it reaches temp, the high pitch sound shuts off.

Never caused a problem but is interesting.....


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carl.swoyer

Well-known member
I also hear a high pitched tone when the hot water heater is operating on electric only. Specifically when the heater is actually heating. Once it reaches temp, the high pitch sound shuts off.

Never caused a problem but is interesting.....


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High pitched?
Like a steam teapot?

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Todster

Active Member
No. More like a circuit board high pitched background tone. Most can’t even hear it.


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