I have a Rheem Elect Hot Water heater that is about 11 years old. The hot water it puts out is not so hot anymore. I am wanting to replace the elements and possibly the thermostats too. I have never done this before. Have any of you? Any tips would be appreciated.
Most electric hot water heaters are simple to fix if that is your problem. The easiest way is to first turn off the power to the unit, disconnect one of the wires to the elements, and using an ohm meter determine which element is open. If you find an element open it is unlikely that you need to replace the thermostats as well.
Turn off the water supply to the water heater and drain the water in the tank to a level below the height of the bad element using the valve on the bottom of the tank. (Opening a faucet in the house higher than the hot water heater will help drain the water from the tank.) Unscrew the element with a pipe wrench or other wrench and pull out the element. Buy a replacement of the same wattage and physical size at HD or Lowes. When installing the new one make sure your gasket area is clean and it might be wise to put some pipe dope on the threads of the element. (You do not want a leak when the water is again turned on.) Once the water level is again covering the elements and the wiring has been replaced, apply power.
It's possible the overtemperature safety has triggered on the thermostat, and simply pressing its reset button may solve everything. Use an insulated stick (plastic pen, chopstick) to press the button so you don't come near any exposed high voltage. The thermostat can allow excessive temperature if it's set too high or even too low, so keep it within the recommended range.
A thermostat is easy to replace, but before working on a water heater for any reason, turn off the circuit breaker, and make sure it's turned off by taking voltage measurements at the screws connected to the wiring on the thermostat. When replacing the thermostat, be sure to get all the wiring right by make a sketch, taking a picture, and labelling each wire.before removing anything.
Measure the resistance across each the heating element. This can be done at the thermostat, unless a wire is loose or shorted. The resistance should be roughly 10-20 ohms, but between either screw and ground (bare metal on heater) it should be nearly infinite. Heating elements are more likely to short to ground rather than open up.
Rheem heating elements screw out, and hardware stores and plumbing supplies sell a socket wrench just for them. A regular mechanic's socket may not be deep enough to clear the end of the element assembly. The cheapest replacement element is just a rod bent in half at the middle, but better elements are much longer, to spread the heat over a greater area so they run cooler and are less likely to have hot spots that boil the water. They're folded over to fit in the heater, and the very best elements are not only bent over but are also bent in an "S" to be even longer. Some premium elements are covered in stainless steel or plastic.
Always drain the heater before removing an element. Turn off the water supply, and open a hot water valve in the house to let air into the tank to displace the water. Always turn off the electricity because a heating element can burn out in a minute if powered and exposed to air (Sandhog brand elements are an exception)... Similarly, be sure the tank is filled completely with water before turning on the power.
Many times when a heating element goes bad in an old tank, the anode rod is gone and the tank is about to leak. 11 years is about time for this if the anode hasn't ever been replaced, so don't be surprised if you need a new heater.
Before you kill yourself, TURN OFF THE FRIGGIN' POWER!
Some elements are bolted in with three or four bolts.
Or use the new gasket for bolted in elements.
Generally the thermostats do not fail, and need not be replaced. In fact, if you were to replace both elements and thermostats, you may be better off replacing the entire heater, as at 11 years, it is likely to be ready to spring a leak anyway...
If it's that old might as well trash it and buy a new more efficient one and downsize if you don't need one that large. No sense maintaining 50 gallons of hot water when you only use 25 gallons or less at a time. You might even look into tankless point of use water heaters.
Buy a new water heater. If you look over your homeowner's insurance, one thing that virtually all policies exclude is water damage from a failed hot water tank which is over some predetermined age, often 5 years. Believe me, it is UGLY when a hot water tank springs a leak and 40 or 50 gallons of water leak out. Murphy's law dictates that this will most likely happen while you away from home for an extended period.
I wonder if there's any reason other than planned obsolescence why manufacturers can't build a tank of stainless steel or at least galvanized steel which won't rust. I know the cost would be higher but they'd last virtually forever.
I had a water heater with a non-metalic tank once. Was fine until it caught on fire! The sad realization was that had we not caught the fire when it first started, it is likely to have spread totally before burning through the tank!
Now, a stainless tank I could see... Most tank damage is however due to the effects of a blown element, the voltage from the element to the tank causes it to quickly eat a hole in the tank.
I haven't found that to be the case, although most of my experience is with gas heaters. Those perforate at the bottom, near the burner. I did have one that perforated at the top, near the flue, but that was due to bad welding at the factory. I was able to solder it a couple of times before it became unfixable.
IME, most electric water heater problems are due to sedimentation. That can be mitigated with a good periodic cleanout; but they all eventually wear out.
Yeah, stainless would be good, at least for electric units. For gas, it might be good as well; but when you overheat stainless steel, it becomes...'not' stainless and subject to rust. I've had that happen to a couple of pieces of cook wear that boiled dry....
The technology exists to prevent this. Ground fault detection circuitry has been available in the marine industry for decades. When you consider that I just got a flyer advertising an entire Dell desktop computer for $299, the price of this circuitry would be, at most, a few dollars added on to a hot water heater. Given the enormous number of hot water tanks sold annually, economy of scale would keep it cheap.
As far as prevention of galvanic corrosion / electrolysis, if I had a stainless steel tank I wouldn't be averse to checking and periodically replacing a sacrificial zinc anode. Come to think of it they could put screw-in zinc anodes into a regular hot water tank too which would completely negate any galvanic potential if the zincs were properly maintained.
If you go through all the trouble to drain the tank and replace an element, put in a new sacrificial anode as well. These usually rot away (as intended) by the time a water heater reaches a decade old.
Paul Hovnanian mailto:Paul@Hovnanian.com
It still gets hot, so both the thermostat and Heating Element are doing their jobs ! Your problem appears to be the need to replace the "Dip Tube" !!! This is a Plastic Insert that feeds the "Cold water IN to the bottom of the Tank" When this fails , cold water "IN" short Circuits to the "Hot Water Out port" resulting in very little "HOT Water" out. Your local Plumbing and Heating Store is VERY familiar with this ! "The middle shelf in row *** "!Labeled "DIP TUBE" ~$4.00! At 11 years you might consider replacement. Energy-Efficient Electric Hot-Water Heaters !! You're kidding ! The only losses are in the piping, so Instant heating might help, but off-peak Electric heating might be more practical
Probably good advice, save one point; most electric water heaters have two heating elements (in fact every one I've seen). When one element--especially the bottom one--goes out, water doesn't get hot very fast.
11yrs. old, it's a safe bet to replace the heating elements w/o worrying about wasting your time and money. I've seen heating element deteriorate and still yield continuity, I've also seen where calcium and mineral deposits give a false reading. The process is pretty straight forward. Turn off the water, drain the tank, disconnect the wires to the elements, screw them out, teflon the new one and reverse procedure. It's also and excellent time to drain and flush the tank (while the elements are out, bigger chunks don't go through the regular drain). I wouldn't worry about the dip tube until the heating elements are replaced as what you've described doesn't indicate a bad dip tube (you really don't want to deal with that 11yr. old can of worms if you don't have to, one step at a time). Tip: Your going to get wet, don't fight it. Have lots of towels and/or a mop handy. used