Water heaters are an important “plumbing appliance” that homeowners rarely think about until they’re standing in the shower and there’s no hot water.
“Then it’s what the!!!“ Followed by a few “Damn, that’s cold!” cries and a hasty retreat out of the shower.
In the next several How To Plumbing posts we’ll be taking an in depth look at water heaters, how they work, how to troubleshoot, among other topics.
In many instances you can take care of your water heater without using a Decatur and Hartselle, AL plumber or plumbing contractor, but there will be times when you definitely want their expertise.
How Does a Water Heater Work?
We’ll start off with the basic tank-style water heater, which most people have in their Decatur and Hartselle, AL homes, condos, or apartments.
This style of water heater heats water on a continual basis, whether you are using hot water or not.
When you use hot water, cold water enters the tank to replace what has been drawn out.
When the thermostat senses the water temperature has dropped below the level you’ve set, it initiates the heating element(s) in an electric water heater or the burner in a gas model.
Here’s an important point to remember: Even if you don’t use hot water, the temperature in the tank will fall and so the water will be periodically reheated to bring it back to the desired temperature. This is wasted energy — and you pay for it each month in your electric or gas bill. Many plumbers and home efficiency energy experts advise turning down the thermostat when you’re away from home for long times or on vacation, saving you money.
Which is Better: Gas or Electric?
Gas and electric water heaters are equally common in Decatur and Hartselle, AL and surrounding communities. An advantage of electric is that they do not require venting of combustion gases like gas models. However, electric heaters may be more expensive to operate and generally do not heat cold water as quickly as gas.
Unless you are building a house and have a choice, you’re pretty much left to what is currently installed because switching from one energy source to another can be prohibitively expensive and would require the expertise of a Decatur and Hartselle, AL plumber or plumbing contractor to pull off.
Deeper Look at Water Heaters
Now let’s get into the nitty gritty of water heaters.
- The cold water supply line connects to the water heater, typically on top of the appliance.
- Instead of dumping the water on top of the hot water in the tank, a dip tube carries the cold water down to the bottom of the tank and the outbound hot water line takes heated water off the top. That way as hot water is used, it is at full temperature. Only after most of the hot water has been used — when the kids take super long showers — will you start to get a hot/cold water mix.
- When you open a hot water faucet in the bathroom or kitchen, the water pressure from the cold water supply line pushes the water out of the heater and refills the tank with cold water. The thermostat(s) sense a lower temperature in the tank and begins the heating mechanism.
- For safety, water heaters have a temperature and pressure relief valve to allow water to escape if the pressure or temperature exceeds the limit of the tank. A tank normally operates up to 150 psi, so a temperate and pressure valve is designed to release water when the pressure exceeds 150 psi and the temperature reaches 210 degrees, which is pretty darn hot.
- In the center of the water heater is the anode, which is sometimes called the sacrificial anode. Its purpose is to corrode instead of the tank corroding. The corrosive action of the hot water attacks the anode, extending the life of the tank. Most tanks have a bonded layer or layers of glass to further protect it from corrosion.
- The bad thing about water heaters is they build up sediment. This sediment should be periodically drained from the tank to increase the life of the appliance and improve heating efficiency — something that many homeowners forget to do. Depending on the water heater’s installation, this could be a very simple process, as simple as opening a drain valve to let the water drain through a pipe to outside the home. If this is not available to you, hook up a hose to the water heater and drain into a nearby bathtub or outside. If you are unsure of draining and refilling the tank, you can always call a Decatur and Hartselle, AL plumber to schedule a water heater checkup, which could run from $75 to $150 depending on the number of water heaters and what is actually done.
Details Unique to an Electric Water Heater
On an electric heater the thermostats are in contact with the tank and operate mechanically. The thermostat is like a switch. The switch is on by default, but when the temperature of the tank rises to a certain point, it expands and pushes a small metal rod against a dimpled piece of metal. That movement breaks the contact in the thermostat and stops current from flowing to the heating elements. The upper thermostat also functions as a reset switch and is sometimes referred to as the ECO (Energy Cut Off). Pressing the ECO restores power to the water heater.
Full size electric water heaters, large enough to handle big families, typically have two heating elements, the upper and the lower. Most models are designed for the elements to operate independently, but in some models they may only operate in tandem. When the thermostats are closed, current flows to the immersion heating elements inside the tank.
Details Unique to a Gas Water Heater
The thermostat on a gas heater is an integral part of the gas control valve and is immersed inside the tank. When the temperature drops, the thermostat signals the gas control valve to supply gas to the burner. However, before it allows gas to flow, the thermocouple must signal that the pilot light is lit, otherwise a dangerous gas leak would occur.
The thermocouple is situated in or near the pilot flame. The heat of the flame creates millivolt current which engages a magnet in the gas valve. The gas valve releases gas in a burner adjacent to the pilot flame and is ignited. If the pilot goes out, the current stops and the magnet disengages, preventing the gas valve from opening.
Gas water heaters must be vented to the outdoors. The combustion of natural gas results in toxic carbon monoxide. In the center of the tank is a flue to carry the gases away to the vent mounted on top of the tank. The vent is critical to your safety because it carries the carbon monoxide outside your home.
You rarely see a Decatur and Hartselle, AL plumber repair a water heater because when it fails it’s dead and gone. You, however, can troubleshoot the water heater for more efficient operation, energy conservation, and money savings — the subject of the next post.