Electric water heater still hissing after draining and flushing

[alienux]

When we moved into our house in 2016, the electric water heater popped loudly when heating. After awhile, I researched and realized that it was likely due to limescale and/or other sediment buildup. I flushed it multiple times, but never got it to stop popping, so I eventually decided to replace it.

I replaced the water heater myself in 2021. It was whisper quiet when heating. Now, after just a couple years, it is making a hissing sound. It's not popping, but it is hissing. Here's a video where you can hear it:



Again, with this newer water heater, less than 2 years old, when it started hissing, I drained and flushed it. After draining, I flushed multiple times before filling it up again and turning it back on. Yet it still makes this hissing noise. Everything I've read says that draining and flushing is the way to deal with this, but it is not helping. The water heater heats just fine, but the noise is an annoyance, especially to my wife.

Also possibly worth mentioning is that we added a water softener around 2018.

What is the next step to deal with the hissing noise? Should I just keep trying to drain and flush it, hoping it will eventually get it cleared? That hasn't helped so far, so I'm not inclined to keep doing it. I don't know if there's some type of cleaning/descaling solution that can be poured into it to help, or if there's something else I should try entirely.

Can someone let me know what the next step would be and/or how to actually effectively deal with this?

 

[Twowaxhack]

Replace the elements, that’s the source that’s the source of the popping. You might could get away with just taking them out, cleaning the scale off and then reinstalling.

Personally, I replace them.

 

[Twowaxhack]

Check your voltage. Higher voltage than the element rating can cause noise.

Try tightening the element. Just moving the element a little can stop harmonic vibration.

Low water pressure, less than about 30 psi can cause noise issues.

 

[Ludington]

That's more of a whistle than a hiss.. mine is just starting to do the same. Much lower but similar.
I know this doesn't answer the question.. but shows your not alone.
I am going to replace mine with a new heatpump style , once they get thier rebates in place. I can get 1750 off, since I'm old and live on ss.

 

[BlueSkyHigh]

I am going to replace mine with a new heatpump style , once they get thier rebates in place.

When you say "heat pump style" is that the same as a tankless, on demand type water heater?

 

[wpns]

While heat pump does sound like a much better idea (much more energy, efficient!) it’s not going to be silent either. It’s going to be significantly more expensive, and I have yet to hear of one that hasn’t failed and been bypassed. Yes, I’m sure the manufacturers will tell you how wonderful they are, but there’s a lot more moving parts and previous generations have been notoriously unreliable.

Caveat Emptor and all that.

 

[Ludington]

I was hoping they had improved. Being I can get 1750 rebate(when available) I thought maybe a good idea. Buut from what you say .. maybe not

 

[wpns]

Sure, but you have to trade off the cost of swapping out the heating element(s), which is what, $100 and something you can do yourself, versus the cost of a heat-pump version ($1500-$3K plus installation, minus the rebate).

 

[Ludington]

Sure, but you have to trade off the cost of swapping out the heating element(s), which is what, $100 and something you can do yourself, versus the cost of a heat-pump version ($1500-$3K plus installation, minus the rebate).

Sure, but you have to trade off the cost of swapping out the heating element(s), which is what, $100 and something you can do yourself, versus the cost of a heat-pump version ($1500-$3K plus installation, minus the rebate).

But my wh is really old ( maytag) not made anymore , and no replacement parts. It takes special elements. So when it does go I'm stuck getting a new one. The third thermostat went a few years back, and I was lucky and found one on ebay. But could never find elements. I'm actually surprised it has lasted this long. It's probably over 25 years old.

 

[wpns]

It's probably over 25 years old.

Ah, that's different, sorry I missed the context switch from the OP's new one to your old one. You're going to pay the install cost anyway, so it'll depend on your different circumstances.

No idea if they are more reliable nowadays, I'd want to wait for the 10-year results, but you can't wait that long. 8*)

 

[Ludington]

Yes, sorry for the unintended hijack. I was probably going to start a thread at some point to see about opinions about them. Big rebate just makes it enticing. I would probably install myself though.

 

[Mitchell-DIY-Guy]

When you say "heat pump style" is that the same as a tankless, on demand type water heater?

Blue, look here: Heat Pump Water Heaters

Basically an air conditioner/heat pump on top of a tank. Of course that's a very simple explanation but not far off the mark.

@alienux I had a completely opposite problem. I installed a new electric water heater for my father, and I thought something was wrong when I did, and filled it and turned it on. Not a peep; no sound whatsoever. I expected to hear some quiet groaning or creaking as things heated up. No, not a sound. I left it on for an hour, and basically hung in the basement with it, and not a sound. After that hour I went upstairs and turned on the hot water...in a few moments, voila: hot water. I was a bit surprised. I expected a little bit of noise!

 

[sarg]

WE clean our electric heater every six months & replace the elements ( under $30.)
We use a wet vac and a length of auto heater hose to remove the sediment through the bottom element hole. That's also the best way to inspect the anode rod.

 

[Mitchell-DIY-Guy]

WE clean our electric heater every six months & replace the elements ( under $30.)
We use a wet vac and a length of auto heater hose to remove the sediment through the bottom element hole. That's also the best way to inspect the anode rod.

HARDCORE Sarg! But I guess that's one way to extend the life of a water heater. You must have a pile of fully functional but 6 month old heating elements around!

 

[sarg]

HARDCORE Sarg! But I guess that's one way to extend the life of a water heater. You must have a pile of fully functional but 6 month old heating elements around!

No used ones .... but at least 4 new ones in queue at all times ...... along with a couple anode rods & thermostats.
Learned my lessons the hard way. In years past we changed to yearly and found the sediment build up "over" the bottom rod which makes them a real pain to remove. We have the PM detail down to under two hours now.
It is no treat to deal with heater issues in February.

 

[sarg]

And today we decided to do the semi-annual PM.
The sediment was indeed up to the bottom element and I had used a Low-density set of elements ... even though I had bad experiences with getting them out before. I will stick with the straight high density rods in the future.

 

[Twowaxhack]

And today we decided to do the semi-annual PM.
The sediment was indeed up to the bottom element and I had used a Low-density set of elements ... even though I had bad experiences with getting them out before. I will stick with the straight high density rods in the future.
View attachment 40240

If your water temp is above 140, it’ll make your problem worse.

 

[sarg]

Our units have always been set at 125 degrees.
It has been a tad confusing in that our well supply must change over time. There was a few years when we could go for 12 months ......... but now it appears six months is best.

 

[Mitchell-DIY-Guy]

Holy cow, @sarg I can see why you are on a six month schedule. Jeez. At least you have your system down pat and can do it quickly and easily.
Does Amazon have the heating elements available on their "subscribe and save" scheduled purchase program? haha

 

[sarg]

The elements are a Camco item through Amazon. I will order another pair this week.