# Tankless Water Heaters



## bluesun7602 (Sep 7, 2005)

My house has the on-demand tankless water heater and it's been great for the last two years, but over the last month or two it's been making me very :rant: !!! Every morning for my shower, the water is hot then after about 5 mins it gets cold and takes another 3 or 4 minutes to heat back up, good for a couple minutes, then repeat.

We tried turning the water temp up, but then that turned out worse than before, it was either scalding or ice cold. We just installed a new showerhead a few months ago, and I'm assuming it's the water-saver-kind. When I do the dishes in the kitchen, the water takes awhile to heat up but then it's good for the entire time. The shower water is where we're having all the issues. (The heater is located in the basement just under the bathroom, and the kitchen sink is on the other side of the house)

Anybody have any tips or ideas before we bite the bullet and call a plumber?


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## Michihunter (Jan 8, 2003)

Sounds to me like 1 of 3 possibilities: 
1)your elements or temp sensor are getting a scale buildup 
2) temp sensor going bad. 
3)your limit is going bad causing the unit to shut down until it resets itself causing the temp fluctuations you are seeing.


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## ih772 (Jan 28, 2003)

There's a diaphragm valve in the heater that varies the amount of gas burned to heat the water depending on the demand for hot water. That valve has a tendency to start sticking after a couple years. Its even worse if the heater is used only occasionally such as a vacation home.


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## Michihunter (Jan 8, 2003)

Make that 4 possibilities:lol::lol:


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## bluesun7602 (Sep 7, 2005)

Thanks! My guess is scale buildup. We have city water, we don't have a water softener, and I've noticed the tub gets buildup fairly quickly after CLR-ing it. I'll present these ideas to the man and see what he can get going. I bought the house from a licensed plumber so I'm assuming he did everything correctly at the time of installation, but in the 2 years we've had the house, the previous owner has proven to not be the smartest at home improvement projects.


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## ih772 (Jan 28, 2003)

Try this trick in the kitchen. Turn on the water and set it to the same temp that you would normally take a shower. Make minute adjustments to change the temperature of the water just like you would if you were in the shower. When the valve is sticking it has a much harder time reacting to the tiny adjustments in water temperature than it does when you're calling for a lot of hot water to wash dishes. This is where the too hot and too cold fun in the shower starts happening. Its even more fun if you throw in the varying pressure of a well and pressure tank. :lol:


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## bluesun7602 (Sep 7, 2005)

Update, we called all the plumbers in the phone book and not a single one will service the on-demand water heaters, but they recommended we call the manufacturer, so we did, which is apparently in Portugal, who then hung up on us... So at this time, I'd highly recommend NOT buying the latest and greatest on-demand tankless water heater.


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## Michihunter (Jan 8, 2003)

bluesun7602 said:


> Update, we called all the plumbers in the phone book and not a single one will service the on-demand water heaters, but they recommended we call the manufacturer, so we did, which is apparently in Portugal, who then hung up on us... So at this time, I'd highly recommend NOT buying the latest and greatest on-demand tankless water heater.


What brand and model?


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## N M Mechanical (Feb 7, 2008)

Another quick check same as using the kithen faucet is remove the shower head or use the tub let run and see if you have the temp swing. Also call a heating contractor not a plumber. We have been installing them for 12 years and providing service.
_Posted via Mobile Device_


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## bluesun7602 (Sep 7, 2005)

Michihunter said:


> What brand and model?


It's Aquastar model AQ-250-SXNG, from 2006.

Heating contractor - check. Thanks guys!


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## Neal (Mar 20, 2001)

> Update, we called all the plumbers in the phone book and not a single one will service the on-demand water heaters


That's because it's a _tankless_ job........sorry


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## jlcrss (May 17, 2006)

Neal said:


> That's because it's a _tankless_ job........sorry


:lol:


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## Michihunter (Jan 8, 2003)

bluesun7602 said:


> It's Aquastar model AQ-250-SXNG, from 2006.
> 
> Heating contractor - check. Thanks guys!


Have you been getting any error codes?


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## Crowhunter (Aug 27, 2005)

You could cut your shower time to 4 min. Bud


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## bluesun7602 (Sep 7, 2005)

Neal said:


> That's because it's a _tankless_ job........sorry


yeah, thanks NEAL....


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## 2britts (Dec 21, 2008)

I had a similar problem at one point it turned out that there was scale built up in the shower head. I would turn the water on and let it run until hot then switch it to the shower head. There was enough water in the lines to run hot for a few minutes then the cold water would make it to the shower. I soaked it in CLR and worked for a while but a better fix was to find a shower head with a higher flow rate.


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## jammydoug (Oct 22, 2010)

Hi
i was very tired when this show was on,but,it was on a home improvement program and it featured a energy efficient water heater that was small,compact and sat on a wall in the garage.it pumped continuous hot water.


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## roger23 (Jan 14, 2001)

I just replaced one with a regular water heater,,I company rep said that it was not back flushed or cleaned ofter enough,,this one was just out of Warranty.this was in a condo and only used on week ends,,,apparently these require a lot of maintenance


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## ih772 (Jan 28, 2003)

bluesun7602 said:


> Update, we called all the plumbers in the phone book and not a single one will service the on-demand water heaters, but they recommended we call the manufacturer, so we did, which is apparently in Portugal, who then hung up on us... So at this time, I'd highly recommend NOT buying the latest and greatest on-demand tankless water heater.


 That's another problem with them, mine was made in France and I can't parlez-vous Français as much as I could in High School.


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## snaggs (Jul 20, 2005)

These new dam confonded conjingled thing-a-ma-jigs things are no better than the good ole fashion stuff. Just ask my wife..she'll tell ya.


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