Not Enough Hot Water

[wizguber]

Greetings Samurai Appliance Gurus !

I come again with questions about my hot water tank.  It's an AO Smith, 50-gal unit fed with natural gas.  Unit was installed in 1999 with new house...yeah the warranty just expired.  To get nice hot water, have been turning up the thermostat little by little.  Currently, is set at the absolute max temp, but the hottest water we get out of the tap (closest sink) is 143F.  With extra folks in the house this weekend, noticed that we ran short of hot water sooner than normal. 

The pilot and burner all look good.  Nice clean flame, good distribution.  Heater flame seems to cycle on/off just fine.  Went to Smith's website and technical bulletin says for low temps to "check the thermostat" and the dip tube.  Short of draining the tank and making a hell of a mess, is there an easier way to do these things ?

Also, at ~7years old, do you folks recommend spending the $100 for a new thermostat (from Smith's website)?  And, if I'm going to take the time to drain the tank and do repairs, should I consider any other overhaul items?

Thanks in advance.

Dave

 

 

[ratherbfishin]

check your dip tube,  its plastic and can deteriorate over time. would explain  prematurely running out of hot water.  check faucet screens at  your sinks for crumbled plastic. it will  look similar to powder laundry detergent.  it causes incoming water to be dumped into top of tank rather than the bottom.  the tube can be purchased at a  plumbing or home improvement store, it's inexpensive.   because you're saying the temp starts at 143 degrees it sounds as if you're heating ok.    damaged dip tube would cause  incoming  cold water mixed with outgoing hot water at top of heater, reducing the temp.    

[russotto]

This guy seems to like water heaters as much as the Samurai likes beer: http://www.waterheaterrescue.com/.

What worked for me when I had a similar problem is a "power flush". Set the heater control to pilot (or off). Shut off the inlet and open a hot tap. Drain the tank. Close the hot tap and open the inlet. Now your tank is part-filled with compressed air. Open the drain valve -- a lot more sediment gets blown out of there than with a regular drain. Close the drain valve again and open a hot tap to get the air back out of the system. Once the air is out, turn the heater back on.

[MrTeach]

Wow...that seems like you want to give me the keys to the palace...you trust me to blow compressed air through my water tank and out the lines and not find my water heating flying through my house and 150 feet into the air?  IF I follow your directions I'll be okay, what if I forget one part of your directions like the typical husband who is not mechanically inclined and wants to fix the water heater so his wife doesn't get just 4 inches of hot water in her tub...my house was built in 1989, and most of our city water comes from wells, and it is very hard water...I drained it last year, and it didn't seem to do much at the time...that's the problem...

[kdog]

if your tank is 7 years old,and you have extremely hard water,chances are good that it has a build up of minerals around the bottom(since minerals deposit when heated) as well as around the thermostat rod. this causes the thermostat to react to temperature changes more slowly(since the deposits act as an insulator), you have a couple of options here- you can simply know this and work around it by running your hot water until the burner fires up which will heat the tank in approx 20 min- then you should have plenty of water available for bath/shower/laundry etc. - you can replace the affected parts which will result in about the same labor cost of having the tank replaced(still leaves you with an old tank) or you can replace it outright. i would try to live with it as it is by forcing it to start prior to using large amts of hot water,and keep your eye peeled for a sale on a decent replacement tank so you can replace it eventually.

[The Seven]

The 40 gal gas water heater was unable to supply enough hot water.

The old dip tube is crack.

The original joints were all soldered and needed to be cut.

A new two-end compression joint is used for easy connection without soldring.

Replaced with a new dip tube and the water heater returns to normal.

[curtiscrowell]

Note that AO Smith had a recall on dip tubes several years ago (less than 10). The old tubes disintegrated.  White plastic, symptoms were as described above with seemingly insufficient hot water.