Cycling occurs when the demand load on the heater is less than the minimum firing rate of the water heater. In other words, if the BTUH required to bring the water temperature up to the set point is less than the minimum BTUH that the water heater can operate at, the heater will keep turning on and off.
The most common problem with water heaters, particularly gas ones, is that they keep turning off, even though they seem to be working properly. This can be due to various issues, such as problems with the gas supply, a dirty or damaged thermocouple, a clogged pilot tube, or issues with the main control valve.
In the average home, the water heater will run for about three hours each day. Total run time can range from one to two hours for new tankless water heaters to five or more hours for older tank style water heaters.
If your water heater is constantly running the first thing you should do is check the unit and the pipes immediately around it for leaks. Your water heater might have insufficient insulation – If the water heater is not properly insulated, it will be unable to maintain the water temperature.
Since the purpose of the water heater is to provide hot water whenever desired, it moves through an unending cycle of heating and reheating your water. Water cools when it rests, so unused hot water eventually cools down, signaling the heating element to activate.
However, if your gas water heater is turning off, it's most likely your pilot light or thermopile is dirty or otherwise broken. The pilot light can get dirty from soot, dust and other particles. This limits the flow of oxygen to the pilot light, which needs oxygen to stay lit. So, it'll flicker off.
Also, tank-type heaters burn energy (gas or electricity) day and night to maintain the water temperature, regardless of whether or not anyone's using hot water, a phenomenon known as standby heat loss.
If your furnace keeps shutting off, check your air vents to see if any of them are closed or blocked in any way. You should keep all your vents open, even in the rooms you don't use. If your heat exchanger doesn't get enough air, it can't transfer enough heat.
A basic water heater will run three to five hours a day to keep its tank heated 24/7.
If your hot water heater temperature switches between hot and cold, there may be a problem with the control thermostat. Your water heater has two thermostats, an upper and lower. Fluctuations between hot and cold temperatures indicate that only the upper water heater circuit is working.
While today's water heaters are better designed than older models, they still require regular maintenance in order to prolong their lives. With regular inspection, draining, and flushing, you can expect a gas water heater to last anywhere from 8-12 years and an electric water heater to last anywhere from 10-15 years.
Gas, electric and tankless water heaters need to be flushed every 6-12 months. This prevents the buildup of sediment, rust and corrosion.
It's generally best to avoid turning your water heater off too regularly. Some homeowners try to save money by switching off their water heaters when they don't need them, but the savings are unlikely to be significant enough to justify the additional wear and tear on your machine.
Problems with your dip tube.
The dip tube is a part of your water heater's tank. The dip tube is responsible for bringing cold water into the tank from the water line, but when it's cracked, broken, or otherwise damaged, that cold water can leak out and mix with the hot water, lowering the temperature.
50-gallon gas water heater – typically takes up to 40-50 minutes to heat 40-degree water to 120 degrees. 80-gallon gas water heater – typically takes up to 60-70 minutes to heat 40-degree water to 120 degrees.
How Much Gas Does a Hot Water Heater Use? Most gas hot water heaters use between 20-50 therms of gas per month. A therm is a unit of measurement for natural gas and is equivalent to 100,000 BTUs. So, if you have a gas hot water heater, it's likely using around 2,000-5,000 BTUs per hour.
If your gas water heater keeps turning off, the problem most likely lies with the thermocouple. This vital component detects when the pilot light is lit and then allows gas to flow to the burner. A faulty thermocouple will shut off gas to the burner as well as the pilot.
Thermostat issues
A faulty thermostat can also be responsible for short cycling problems. The thermostat provides your furnace or heat pump with instructions about when to run, based on the indoor temperature.
If your furnace shuts down after a few minutes, it's likely due to a faulty or unhygienic flame sensor. This crucial component intends to monitor the gas burner. Also, when a flame sensor cannot detect the burner, the furnace runs for a few moments before shutting down and restarting.
If the pilot light goes out on a storage or instantaneous hot water heater, space heater or a ducted heater, you will not have a gas leak. This is because all modern gas appliances with pilot lights have a fail-safe device that closes off the gas to the appliance in the case when the pilot may go out.
Although this is an area of concern for many people, the reality is that boilers are built so that the gas supply to the pilot light is shut off if the flame goes out. Whilst the cause of pilot light failure needs to be investigated, extinguished pilot lights aren't going to cause a gas leak.
That's important because gas is always being supplied to the pilot to keep the flame lit. But if the pilot flame goes out, then the gas would still be released. After a while, the gas could collect in your home and become a health hazard.
Water heaters don't last forever. Sometimes components fail (such as thermostat, gas control valve, heating coils in electric units, and Temperature & Pressure (T&P) valve). These parts can often be replaced without replacing the water heater. The most common failure is a leak in the water storage tank.