Water heater question(s)

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Trent Mason

New User
Trent Mason
OK all you DIY'ers, I've got a question for you.

Back around Thanksgiving we suddenly noticed that our hot water ran out after about 20 minutes. We never had a problem with it before. Of course, we are renting and I'm not the one fixing this, but even the maintenance guys seem to be at a loss.

Specifically: we used to turn the knob in the shower to about "5 o'clock" and it would stay that temperature for as long as either of us were in the shower. Around Thanksgiving, we had to start turning the knob to "7 o'clock" and further about every five minutes until it would eventually turn ice cold after around 20 minutes. :BangHead::BangHead::BangHead:

Over the last month and a half, the maintenance guys have come out several times. They have replaced both elements and the top thermostat, yet the problem still persists. The water heater is about 10 years old, so it may be on its way out anyway. Any thoughts????? :help:
 

scsmith42

New User
Scott Smith
Trent, if it were me I would use up the hot water, and then check the current flow on the top element with a meter. It should be somewhere near the listed wattage (usually 4500 watts). Every 15 minutes afterward for the next hour, check the current flow on the bottom element. The top element's thermostat should be set to a lower temp than the bottom element. Once the top of the tank achieves the temp setting, the thermostat should switch power to the bottom element in order to heat up the rest of the tank.

I'm guessing that only your top element is working, or that you have some resistance somewhere in the circuit feeding the WH. The latter could be a fire hazard, so you definitely want to get it figured out soon.
 

Gotcha6

Dennis
Corporate Member
If both elements are new and the wiring is correct, look for a failed dip tube. This is a plastic tube on the inlet side of the heater that makes the cold incoming water go to the bottom of the tank. If it has failed, the incoming cold will mix with the outgoing hot water and you know the rest.........:cry_smile
The maintenance people will need to disconnect the cold side of the heater and remove the inlet nipple. It usually has a flare on the top and can be removed without draining the tank fully provided the water (and power) are turned off. Replacement tubes are available from the local plumbing supply distributor selling the water heater.
 

Gotcha6

Dennis
Corporate Member
Tarhead Re: Water heater question(s)
Make sure it's not loaded up with sludge.

....you mean like this?



This is what came out of a water heater core I converted to a dust cyclone.:tinysmile_tongue_t::tinysmile_tongue_t:
 

Trent Mason

New User
Trent Mason
Thanks so much for the replies fellas. :notworthy: I'll pass this along to the maintenance guys. If you have any other thoughts, feel free to fire away. :qleft7:
 

Tarhead

Mark
Corporate Member
Make sure it's not loaded up with sludge.

....you mean like this?



This is what came out of a water heater core I converted to a dust cyclone.:tinysmile_tongue_t::tinysmile_tongue_t:
Now doesn't that make you want to take a shower?:rotflm:
 

junquecol

Bruce
User
Because you are only getting a little hot water, most likely this means lower element isn't coming on. You said they haven't replaced lower thermostat DUH!
 

TracyP

Administrator , Forum Moderator
Tracy
I have a Rinnai "spelling" :icon_scra, tankless water heater powered by Natural Gas. It takes a few minutes to get up to temp but provides endless hot water. I have ran hot water to a pressure washer for over ten hours at a time while cleaning my house. It also is a power saver as it only heats water on demand. No need to keep the tank hot all the time. Had it for 5+ years and have never had a day without hot water. Could be a saving for the landlord in the long run. No tanks to corrode, no elements to fail. JMTCW:wwink:
 

ehpoole

Administrator
Ethan
I'm commenting a bit late, buy my vote is very much with the others who have suggested your lower heating element is no longer working. It is a symptom I've seen quite often and it is nearly always a sign that the lower heating element needs replacing (in an electric water heater).

This time of the year the symptoms tend to be even more pronounced and dramatic than at other times of the year due to how cold the incoming cold water tends to be during winter months. The typical experience is to have perfectly warm water one moment, followed by a few seconds of rapidly cooling water, followed by cold water all over a very short span of time. An inversion layer will form between the hot water in the upper portion of the tank above the heating element (and its thermostat) and the much colder water immediately below. As you consume the hot water from the top of the tank the cold water layer advances upward until it reaches the hotwater outlet at which point your shower very suddenly turns cold.

Fortunately replacing a heating element is a trivial job (even for a DIY'er) that takes only a few minutes and a proper sized wrench. For the DIY'er, you will want to power off the tank and drain it to a level below the level of the heating element (or simply drain the tank entirely as below). You then disconnect two power wires and use an appropriate wrench (for DIY'ers a suitable wrench can be purchased cheaply at the same hardware store you purchased your heating element from) to unscrew the heating element. Take the old element to the hardware store and purchase a new element with the same size and wattage. Then screw the replacement element back in and reconnect the two power wires.

FYI: While the heating element is by far the most common cause, it can also be caused by a failed thermostat module. A thermostat replacement is a little more complicated for those not comfortable with electrical wiring (though no problem for those with competent elecrical skill) and there are a wider variety of thermostat modules, so you will need to find a comparable replacement (do not retrofit a different style of thermostat unless you genuinely know what you are doing -- the upper thermostat is also a safety item designed to cut out if the temperature ever rises dangerously high).

It is good maintainance to periodically drain (depending on how much sediment is in your water) your water heater (be sure to turn off the power or pilot flame first) to remove the sludge that settles at the bottom of most any hotwater tank. Attach a standard garden hose to the drain **** located at the bottom of the water heater and run the hose outside to a level below that of the water heater. When finished draining the tank, open the hot-water side of all your faucets, then refill the tank. When you get only water, and no air, from each faucet you can shut off that faucet. Once the tank is filled and all the air has been purged, turn the power on or relight the pilot flame).

But for sludge to be a heating problem in an electric water heater, you would have to have an almost unimaginable amount of sediment before the sludge encased the lower element.
 

petebucy4638

Pete
Senior User
OK all you DIY'ers, I've got a question for you.

Back around Thanksgiving we suddenly noticed that our hot water ran out after about 20 minutes. We never had a problem with it before. Of course, we are renting and I'm not the one fixing this, but even the maintenance guys seem to be at a loss.

Specifically: we used to turn the knob in the shower to about "5 o'clock" and it would stay that temperature for as long as either of us were in the shower. Around Thanksgiving, we had to start turning the knob to "7 o'clock" and further about every five minutes until it would eventually turn ice cold after around 20 minutes. :BangHead::BangHead::BangHead:

Over the last month and a half, the maintenance guys have come out several times. They have replaced both elements and the top thermostat, yet the problem still persists. The water heater is about 10 years old, so it may be on its way out anyway. Any thoughts????? :help:
A lot of these maintainance guys don't have a clue. I know a few of them who don't know how to do much more than replace the parts that they recognize and usually isn't all of them.

I'd put an amp meter on each of the conductors feeding the elements, then run the hot water and see if they turn on and if they are drawing near their specified loads. That should tell you if the elements are operating. With new elements in place, I'd be looking for a bad thermostat. Considering the age of the units, as a landlord I'd probably just toss it and put in a new one.

Pete
 

DWSmith

New User
David
I looked at a tank-less water heater prior to replacing the old electric heater we had. Purchasing the heater, paying for the installation and resizing the gas line to accommodate the heater would have cost about $3500. The new heater cost $600 installed. The tank-less heater would have paid for itself in three to five years depending on use but I couldn't justify the enormous upfront costs. Once their popularity declines I might look at one again.

BTW When the installers removed the old 50 gallon tank, after 17 years it was over 1/3 full of sludge. They advised me to connect a hose to the tank once a year and let it drain to clear out the accumulated sludge.
 

petebucy4638

Pete
Senior User
I looked at a tank-less water heater prior to replacing the old electric heater we had. Purchasing the heater, paying for the installation and resizing the gas line to accommodate the heater would have cost about $3500. The new heater cost $600 installed. The tank-less heater would have paid for itself in three to five years depending on use but I couldn't justify the enormous upfront costs. Once their popularity declines I might look at one again.

BTW When the installers removed the old 50 gallon tank, after 17 years it was over 1/3 full of sludge. They advised me to connect a hose to the tank once a year and let it drain to clear out the accumulated sludge.
One of the flaws of tankless water heaters is that if the flow drops below a certain point it will turn off the burner or heating element. Some are worse than others in this regard. If someone tries to save water in the shower by turning the flow down low he can find himself taking an unexpected cold shower.

The best way to save energy with a conventional electric water heater is to put a time on it.

Pete
 

aplpickr

New User
Bill
Pete: the payback on a hot water heater timer is ~10 years. The cost of hot water is from heating it, not keeping it hot. Take a heater at temp. Turn off the breaker. Allow to stand unused for 24 hours. Now use the water. With modern day foam insulation it will still be hot. Touch the outside of a heater at temp. Is it warm, it has to be warm if it is leaking heat.

Typical heating cost is 10 gal x 8.3 #/gal x 70° rise x 1 BTU/#/° rise x 30 days /3416 BTU/KWH x $0.103 /KWH=~$5.25. Figure your daily use of 10 gal of hot water and you will find that the average family will have a water heating bill of ~$40. You have to figure showers, hand washing, dish washing, clothes washing, etc. :)
 

petebucy4638

Pete
Senior User
Pete: the payback on a hot water heater timer is ~10 years. The cost of hot water is from heating it, not keeping it hot. Take a heater at temp. Turn off the breaker. Allow to stand unused for 24 hours. Now use the water. With modern day foam insulation it will still be hot. Touch the outside of a heater at temp. Is it warm, it has to be warm if it is leaking heat.

Typical heating cost is 10 gal x 8.3 #/gal x 70° rise x 1 BTU/#/° rise x 30 days /3416 BTU/KWH x $0.103 /KWH=~$5.25. Figure your daily use of 10 gal of hot water and you will find that the average family will have a water heating bill of ~$40. You have to figure showers, hand washing, dish washing, clothes washing, etc. :)
I have to disagree with you about the payback time frame on a hot water heater timer. It costs money to keep water hot, even in a modern well-insulated water heater. There are many homes where the vast majority of hot water is used between 6:00 pm and 9:00 pm. The rest of the day no one is at home to use it. Most water heaters when turned off will keep water hot enough over night for the morning wash up before work and school.

A timer lets you keep the water heater off for most of the day. Programmable thermostats for HVAC units do the same thing. There is no reason to keep a house at 72 degrees in the summer when no one is there. The old adage that you will use just as much power cooling the house off when you get home was disproven years ago.

A water heater time costs me about $25 wholesale and I can install one in about fifteen minutes.

Pete
 

aplpickr

New User
Bill
Pete: The average person will pay about $90 to get one installed. The fact that the water is still hot with a timer proves my point, if they don't cool down then what have you LOST?
 

petebucy4638

Pete
Senior User
Pete: The average person will pay about $90 to get one installed. The fact that the water is still hot with a timer proves my point, if they don't cool down then what have you LOST?
The water is hot enough to wash your face and you might even get in a very quick shower. But that is about it. Even a vacuum bottle loses heat over time and a water heater is not as efficient at retaining heat as a vacuum bottle. By having a timer turn off the water heater for the many hours that you are not using it, you will save the cost of keeping the water at peak temperature when it is not needed. It's like using a programmable thermostat to reduce cooling or heating loads when you are not home.

If all a timer does is save you 10%, which in my experience is lower than what most users save, it is a worthwhile investment. At 10% it would save you $4.00 per month on a $40.00 water heater energy bill. That would work out to $48.00 per year or $480.00 over a ten year period. That is a pretty quck pay back even at only a 10% savings. In my experince, the savings usually work out to over 20%, so the payback would be even faster.

Timers also extend the life of both heating elements and thermostats. The less that they are used, the longer they will last.

Pete
 

JRD

New User
Jim
I too have a tankless water heater, and am very satisfied with it. Especially never running out of hot water.

However, it has major flaw as I see it. If power is out, say an ice storm, there's nothing to spark the flame until power comes back on. With a conventional modern water heater at least you have
a ready, if somewhat limited, supply of hot water stored in the tank.

The flaw in the tankless version would have been so easy to fix with a capacitor to store up several "sparks" for when power fails. I guess no one thought of it.

Jim
 

petebucy4638

Pete
Senior User
I too have a tankless water heater, and am very satisfied with it. Especially never running out of hot water.

However, it has major flaw as I see it. If power is out, say an ice storm, there's nothing to spark the flame until power comes back on. With a conventional modern water heater at least you have
a ready, if somewhat limited, supply of hot water stored in the tank.

The flaw in the tankless version would have been so easy to fix with a capacitor to store up several "sparks" for when power fails. I guess no one thought of it.

Jim
Some tankless water heaters actually have a backup battery that can keep it going for a day or two, sometimes longer. It does not take all that much power to keep on-line. Some of the tankless water heaters used to use a pilot, just like a conventional gas water heater. My guess is that they have mostly migrated over to electronic igniters. Once the early demand for them faded, I didn't keep up with the technology.

At my house I have a direct-vent, natural gas water heater. I have near limitless hot water even with the power off. The cook top is gas too as is one of the fireplaces. If we lose power and I don't feel like fiddling with the generator, I can stay pretty comfortable during even the worst ice storm.

Pete
 

aplpickr

New User
Bill
Pete:
Duke Power's website lists the following to reduce water heating costs: turn down the thermostats, insulate the heater and piping, minimize water use, fix drippy faucets, upgrade shower heads, and/or install a softener. They do not mention timers!
Are you saying that the small amount of water neccessary for the morning is all the hot water that is left? Either all the water is still hot or not. With the timer in the off position, incoming water mixes with the hot water and lowers the apparent water temp. Web research is vastly provided by the manufacturers and sellers of timers. They do not tell the whole story,
http://michaelbluejay.com/electricity/waterheatertimer.html . If you shut the heater down before it recovers from the evening load it will not be hot in the morning.

Unfortunately when energy-cost concerned people make changes they make many of them: timers, thermostats, insulation, new heat pumps, duct pipe insulation, windows, storm doors, etc. It is therefore very difficult to assertain the true savings credit!
 
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