Water Heater Repair: Not Enough Hot Water. “Hot water heater.” What is a “hot water heater”? When I was growing up and the kids in the neighborhood wanted to get a ball game going, I would always want to be the “hind catcher”. What is a “hind catcher”? My brother asked me if I wanted to catch “hinnies”… Folks, it’s not a “hot water heater”. If the water is already hot, why would you want to heat it. Altogether now, “Water Heater”! It is a device that takes cold water and heats it to a comfortable temperature. Now that we’ve gotten terminology straight, let’s get to some of the problems with your water heater and some solutions. The one thing that we will not cover is a leaking tank. If your tank is leaking the only viable recourse is to replace the unit. But, leaking tanks don’t usually have anything to do with the amount of hot water coming from your water heater. If the tank is leaking that badly, you definitely have a problem that needs to be addressed. Don’t let your unit intimidate you. The average household water heater is the easiest thing in the world to work on. Most replacement parts can be purchased at your local hardware store or home improvement center. In this article we will be looking at electric water heaters, and mainly water heaters that have at least two elements in them. That’s what most homes have in them today. A word of caution: WARNING! Electricity and water don’t mix, well, that’s unless you’re using the water as an active current carrier in such contraptions that have water level sensing circuits. (the voltage is in micro and milli volts in those circuits) In all seriousness, make sure the power is off to the water heater before you begin any of these tests or repairs. Also, make sure the tank is completely full of water before you return power to the unit. You can go though the whole process of draining the tank, replacing an element, and then burn out the element in just a few seconds…if you forget to completely fill the tank before returning power (flipping the breaker back on). Some tests are accomplished with the power on, but unless you are good with a test meter, try sticking to “continuity” tests only. (NO POWER ON) 1. Too much “sludge” in the tank. This one is simple. Over years, mud and stuff can build up in the bottom of your tank and prevent the bottom element from actually heating water. It can also shorten the life of the element and the tank. An easy way to check if “sludge” is your problem is to slowly open the tank drain valve on the bottom of the unit. Place a pan of some sort under the valve. If you slowly open the valve and notice that water is not “pouring” out the valve, or, “sludge” looking stuff is coming out, your tank needs to be flushed. That being the case, Kill the power to the unit. Turn the incoming water to the unit off. Attach to the drain valve a hose long enough to route the water outside. Open a hot water faucet somewhere in the house (actually the more the better). Open the tank drain valve and allow the tank to completely drain. When the water stops flowing out the hose, turn the incoming water to the tank back on. Allow it to run long enough until you notice only clear cold water coming out the hose. Shut off the drain valve. Leaving the incoming water on, and at least one faucet open, allow the tank to refill until water starts to come out the open faucet. Close off that faucet and then turn the power back on to the unit. 2. Thermostat turned down too low. (I would advise your checking the condition of the element first – see below – because, if the element is good, your t-stat is probably the culprit) This is a simple one, also. With today’s emphasis being on energy savings and hot water burns, a lot of “manufactories” are sending their units out with the temp turned down to around 120 to 140 degrees. If you own a bank, or a large corporation and can afford the high cost of electricity, you might want to turn the thermostat up a little. After killing the power, remove the cover from the top element (it’s a panel on the side of the water heater – usually held in by one screw in the top). Most water heaters use a separate adjustable t-stat on each element, some have one. Once you have the cover off, you will notice a slotted post with a graduated dial on the body of the t-stat (that means it’s got numbers on it). This might be covered with a stiff, plastic protective cover. You can adjust the temperature up or down by turning the pointer to the appropriate number. Just remember, the hotter the water the more likely someone is going to get scalded. If you have small children that like to play with the tub faucet while they’re taking a bath, please be careful. (And your electric bill will be higher.) Follow this procedure for both the top and bottom element thermostats. It is also possible that – as the years go by – the t-stat might lose its sensitivity and need some slight “tweaking” (or turning up a little). If the t-stat needs replacing, draw a diagram of where each wire goes. Remove the wires from the terminals. Slide the t-stat out from under the hold-down bracket. (You do not have to drain the tank for this type control) Slide the new one in its place. Looking at your drawing, replace the wires exactly as they came off the defective t-stat. Set the temp to the desired level. Replace the cover and return power to the unit. 3. The Thermostat high-limit has tripped. This device is a protective device to keep the unit from overheating and building up enough pressure in the system to rupture the tank or lines. There is also a device called a “TP” valve which is mounted on the side that protects from too much pressure, but we will cover it later. On my water heater, there are two high-limits. Some units have only one. It is a small box looking device that has a red button right smack dab in the middle. On some occasions, when the water gets too hot because of continual use, or the operating thermostat is turned too high, the limit will snap open the contacts within it, and shut power off to the element(s). Once you have removed the element cover plate and have found the red button of the high limit, press this button until you hear a snap. If you hear, or feel, the snap, the high-limit has been reset. The water heater should begin to heat properly. If you do not hear the snap, then something else is wrong. Also look for constant resetting of this device. If you have to constantly reset it, either it needs to be replaced or there are other problems. (Such as the operating thermostat may be set too high or is defective and won’t cycle off.) If your tank has only one high-limit, and it has tripped, you will have NO hot water once the heated water held in the tank is replaced with incoming cold water (or you reset the limit). If this limit needs to be replaced, follow the operating thermostat removal guidelines above. Many of these limits come as an assembly with the operating thermostat. Replace the cover. Turn the power on to the unit. 4. The “TP” valve is open or leaking. “TP” stands for “temperature and pressure.” This device is a brass valve mounted on the side of your water heater. It should have a pipe running from it to the outside of your home, or at least to a pan in which the water heater is sitting. When the temperature or the water pressure reaches a preset safety level, this device will open and prevent the pressure from building up to dangerous levels. The water and pressure will be expelled to the outside or into the pan. You will also notice that there is a lever on the valve in which you can manually release pressure or check water flow by pulling the lever up. It is a good idea to check this valve periodically, by pulling the lever. This makes sure that the shut off valve inside the valve body is working, and that contaminants are flushed out the valve. Over years, this valve can begin to break down and start to leak. If the leak is large enough you will constantly lose hot water and cold water will replace the outgoing hot water. This will mean that your unit is having to heat almost constantly, which will run your electric bill sky high. (If you have a higher than normal electric bill, check this valve.) If the valve continues to leak, turn the power and water off to the unit and go through the procedure of draining the tank as mentioned previously. You don’t have to drain the tank completely. Just drain the tank until no more water comes out the open “TP” valve. Remove the defective valve from the unit. (You will have to remove any tubing or pipes that are connected to the valve). Replace the valve with one that has the exact temperature and pressure setting as the defective one. Before installing the new one, coat the threads with a good thread sealant that can be purchased at the hardware store (you can get this stuff at Wal-Mart). Reinstall the pipes or tubing that direct the water outside or into the pan. With a faucet still open, turn the water on and allow the water to fill until it comes out the faucet. Turn off the faucet. Check for leaks around the valve. Lift the lever on the new valve a few times to expel some water and flush any thread sealant out of the valve. Allow power to be returned to the water heater and then watch for leaks that might develop when the water is hot and the tank is under pressure. 5. Element(s). Most water heaters have at least two elements. If your unit has only one element, your problem will not be “not enough hot water” – but no hot water – if the problem is the element. Elements come in a couple different mounting styles. Some screw in. Some have a flat mounting plate. Some have a plate with “dog-ear” or raised areas on the plate where the screws go through. When you replace an element, always replace the defective element with one of the same mounting, voltage, and wattage. This information is imprinted on the body of the element, or is embossed into the mounting plate. As a rule of thumb on dual element water heaters, if your problem is element related, there will be no hot water – if the top element is not working or is not getting power. If your bottom element is not working or is not getting power to it, you will not have ENOUGH hot water. When a water heater is working properly, the top element will heat the top half of the tank first. When that t-stat is satisfied, it will redirect the current to the bottom element and the bottom half of the tank will heat until its t-stat is satisfied. This cycle will continue until both t-stats are satisfied. So, with that in mind, if you do not have enough hot water, it is usually the bottom element that is out or is not getting voltage from its t-stat. The easiest way of checking this is to kill the power, remove the cover, access the element, remove the wires from the element terminals, and with your handy-dandy multi-meter check for continuity across the element terminals. If your meter does not send the pointer across the scale, then your element is open and needs replacing. Before you think the element to be good because you got pointer movement (you can get a false reading through the water), take one probe and place it on one of the element contacts and the other on the metal tank. You should not get movement of your pointer on the meter. Then take the probe and touch the other element terminal to make sure there is no pointer movement. If you do get a reading when checking “to ground”, it means your element has broken and is shorting through the water to the tank. The element is definitely broken and needs replacing. To replace the element. Follow the tank draining procedures listed previously. With the wires still removed, carefully remove the element by either unscrewing it or removing the four bolts that hold it in the tank. (You can purchase a special socket to remove the screw-in type elements at your local home improvement store or hardware.) Taking an element of the same voltage and wattage, install the new element. On the screw-in elements, use some thread sealant on the threads. Do not over tighten. Once the new element has been installed, replace the wiring, and the t-stat components. Follow the refill procedures listed previously and check for leaks. If there are no leaks and the wiring is back to normal and the tank is full, replace the cover, and return power to the unit. If it does not explode! Well, if it does not trip the breaker or blow a fuse and you hear the water start to heat, you can pat yourself on the back and feel proud about saving yourself a couple hundred bucks. Again, this is not all inclusive. There can be other causes, but we’re looking for the most obvious and the safest for you to tackle.
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