No matter what type of water heater you have, you should always make sure to have it drained and flushed every year. Not flushing your water heater regularly will negatively impact its performance and also shorten its lifespan. We’re going to discuss the purpose of flushing a water heater and also what can happen if you don’t flush your unit.
How Sediment Forms in a Tank-Type Water Heater
Flushing a tank-type water heater is important as it allows all the sediment that forms inside the tank to be removed. The water in your home contains at least some dissolved or suspended minerals, like magnesium and calcium. During the heating process when the unit is actively running, some of these minerals undergo a change and solidify into small pieces of sediment.
This sediment will continue to build up over time to the point where it can eventually interfere with the water heater’s ability to function properly. If you live in an area with hard water, your home’s water contains a much higher concentration of minerals, so the sediment will build up more quickly. As such, you may want to have your water heater drained and flushed every six months instead of just once a year.
How Sediment Affects a Gas Water Heater
Sediment build-up impacts both gas and electric water heaters, but the problem is typically worse with gas units. When a gas water heater is running, some heat is transferred to the water via the hot combustion fumes that flow up through the exhaust flue. However, the majority of the heat comes directly from the gas burner underneath the tank. As the sediment builds up, it begins to insulate the bottom of the tank so that less heat flows out into the water. This results in the water not heating as quickly, which means the unit will have to stay on for longer and use more gas.
Another issue is that the sediment will absorb and hold on to most of the heat the burner produces. This can create hot spots at the bottom of the tank that can start to weaken the steel tank and increase the chances of the unit eventually starting to leak. This is just one of the several reasons why not flushing a water heater will usually lead to it having a much shorter lifespan and failing more quickly. The fact that the unit will have to run for longer times can also negatively impact its lifespan as it leads to greater wear and tear.
Sediment build-up can also lead to increased recovery times, which is how long it takes for the water to reheat after most of the hot water in the tank has been used up. The recovery time for a gas water heater is usually around 30 minutes to an hour, but this can vary depending on the size of the tank. When a water heater isn’t flushed regularly and has lots of sediment, you may need to wait as long as two hours or more before the unit can fully reheat.
Having lots of sediment in your water heater tank can also often lead to the unit producing a loud knocking sound every time it runs. Whenever the water is heated, small bubbles of air rise up through the water. When there is lots of sediment build-up, the bubbles can disturb pieces of the sediment causing them to hit the sides of the tank and make a loud knocking sound.
The Impact of Sediment on Electric Water Heaters
Instead of heating directly from the bottom, electric water heaters have two electric heating elements in different parts of the tank. The lower heating element is in the bottom third of the tank, and the upper heating element is somewhere in the middle or top third of the tank. If you don’t have the unit flushed annually, the sediment can build up to where it reaches the lower heating element. When this happens, you’ll again have issues with the unit heating more slowly, and it will have a longer recovery time. You’ll also often run out of hot water more quickly or experience more issues with temperature fluctuations.
When there is lots of sediment in the tank, the lower heating element will often end up wearing out more quickly and eventually will need to be replaced. As with gas units, the sediment can create hot spots or lead to knocking noises if it builds up to where it comes into contact with the lower heating element.
Can You Flush a Water Heater Yourself?
While flushing a water heater is something you can do on your own, most experts recommend always hiring a plumber to do the task for you. One reason is that your water heater should always be inspected and fully serviced every year. Part of this involves draining the tank so it only makes sense that you’d also have the plumber flush out the sediment at the same time.
Another reason is that the sediment can often clog the drain valve and prevent more water from coming out, and a plumber will have all the tools and experience necessary to unclog the valve. In some cases, the only way to unclog the valve is to use a hose and connect the unit to another water source so that it can be back-flushed to clear out the sediment from the valve. There are also times when the valve can become completely clogged to when the only option is to remove it and install a new one, and this is definitely not something you should try on your own.
Why Tankless Water Heaters Need Drained and Cleaned
Sediment isn’t an issue you need to worry about if you have a tankless water heater. Nonetheless, tankless units should still always be drained, flushed and cleaned every year, and the reason for this still has to do with the minerals in your water. Sediment won’t form since tankless water heaters instantly heat the water flowing through the unit instead of storing water, but mineral deposits and limescale can form inside the unit.
Limescale will always build up on the unit’s metal heat exchanger over time, which prevents the water flowing through the unit from directly contacting the metal. As such, less heat will flow out into the water, which can result in the water taking longer to heat up or never getting as hot as you want. Draining and cleaning a tankless water heater essentially descales the heat exchanger and removes all of the limescale build-up. This helps to ensure the unit works energy efficiently and can also help to improve its lifespan.
Las Vegas’ Water Heater and Plumbing Professionals
If your water heater needs to be flushed, serviced or repaired, you can count on the professionals at BEST Air Conditioning Plumbing Repair for help. We work on traditional and tankless water heaters, and we can also help with water heater replacement and installation. We’re proud to be one of the top-rated contractors in the area so contact us today for all your water heater, plumbing and HVAC needs.
