If you are the owner of an older tank-type water heater, no matter is it Rheem, AO Smith, Bradford White, Kenmore or any other brand, gas or electric, you have probably noticed that your water heater is not performing as well as before? Or, maybe the performance is down and the unit is not as efficient as it used to be, resulting in higher bills?
Does it take more time to heat the water and reach the set temperature; also you can hear an unusual sound, and the energy usage has increased?
These signs are the most distinctive proofs that sediments or mineral deposits are accumulated inside the heater’s tank and its elements. The common name for deposit is "scale," and the cause is – hard water.
So, what can be done when the water coming from the water supply system is more or less hard?
There are a few solutions which plumbers recommend, but let's first clarify how water becomes hard, or why it is soft in Vancouver and New York, hard in Toronto and New Orleans, and extremely hard in Regina and Las Vegas.
Imagine rain falling, soaking the soil, gravel, rocks... On its journey to the depth of the earth, the water dissolves some structures, and the elements such as metal ions became a part of the water. You don't need to know the whole chemical process, but remember that water hardness depends on at least two factors – the quality of the soil, and water characteristics. After all, water supply companies deliver water not only from natural underground reservoirs and springs but also from lakes, rivers...
When you consider all this, it is clear why differences appear.
Water hardness usually refers to the presence of calcium and magnesium ions. You can see them easily as fine white deposits on the taps, tiles an especially inside the dark pot in which water was boiling. If you don't remove residues, deposits will build up, which is exactly what happens inside a water heater.
There are different measurement units to determine calcium presence in water, but let's consider grain per gallon (gpg), defined as one grain (64.8 mg) of calcium carbonate dissolved in one US gallon of water. Here is a short table which shows different levels of hardness:
The tap water in Vancouver is soft (0.3 gpg), in Toronto it is hard (7.5 gpg), but in Calgary and Regina, the water is very hard, 11.7 and 29 respectively.
You can find information about water hardness in your municipality on the internet, or from the water supplier. Check out the map of hard water in North America.
Be prepared to take some measures permanently if you live in areas with hard water.
Let's go back to the hot water heaters.
There are some differences between the damage caused by scaling on electric and gas water heaters, but the common problem is poor heat transfer to the water and lower efficiency.
In electric water heaters, the scale is forming on the heating element first, then crushes and falls to the bottom. The efficiency of the heating element decreases, and it eventually overheats and burns out.
As the gas burner and flame in gas water heaters are located at the bottom, so when water is heated the sediment buildup will act as an insulator reducing the energy transfer. Thus, the tank becomes overheated which may lead to failure, cracking and eventually leaking. Deposits on the bottom of the tank in both types may be increased so much that holding capacity becomes reduced.
In a tankless water heater, the scale is forming slower and later, because of continuous water flow and high velocity of water, but some parts are threatened yet.
For easier draining and flushing of tankless water heaters, it is recommended to use isolation valves and flush kits.
Some tankless models are equipped with the features which enable or reduce the risk of the scale build-up, while the advance electronics inform if such problem occurred, by displaying an error code. Due to the delicate elements and safety in general, this work should be performed by the licensed plumber.
To sum up: Hard water is bad for water heaters. The most powerful solution to eliminate water hardness is to install a water softener.
Water softeners remove calcium, magnesium and other particles from the water through an ion exchanging process. There are many types of water softening systems, packed into the well-designed cabinet(s), equipped with additional features.
They remove minerals from the place where plumbing pipes enter into your home so that all appliances are protected. An average softener costs a few hundred dollars, more or less expensive softeners are also available, but keep in mind that all require regular maintenance for the long-term operation.
Some water heater manufacturers offer unique softeners for their heaters, for example, Noritz, which proposes its Scale Shield – Anti-Scale Hard Water Treatment System for tankless water heaters.
Tip: Water softener system may be rented, check out this option, too.
Flushing is the next preventive maintenance to keep your hot water heater protected from the sediment buildup and potential damages. If you drain and flush the tank regularly, the scale will not accumulate into a thick layer. The frequency of this method depends on water hardness and should be done at least once a year.
If the home water is very hard, you might have to flush the system more often – even three times a year which will lead to water, energy and time waste. Some technicians recommend using cider vinegar for cleaning, but be careful in any case– if the tank is old the cleaning process can bring more bad than good, especially if it is done unprofessionally.
As the risk of scale buildup increases with a rise of the water temperature, follow the manufacturer's instructions, adjust the thermostat properly and avoid temperature settings above 120 degrees Fahrenheit.
Hard water makes additional expenses for your household budget; it shortens the lifespan of water heaters, washing machines, dishwashers, coffeemakers and all appliances that warm up the water. Hard water also reduces the life and functionality of fixtures and plumbing pipes.
The deposits remain hidden in the interior, inaccessible to day-to-day maintenance, so you need to think on time, and take steps advised by experts.
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