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House Water Heater
House Water Heater photos: P 39-P 46, P 206
Usually the water heaters are a separate unit but can be immersion coils inside boilers. An immersion coil system has water pipes that carry cold water inside a coil located in the side of the boiler. The coils are immersed in the hot boiler water, hence you get the name immersion coils.
The cold water in the pipes doesn't mix with the boiler water. If it did, then the dirty boiler water would be carried back to the faucets and showers. This would be a health problem. The cold water is kept inside pipes that look like a snake with many different loops inside the boiler. The purpose of the coils is to allow the cold water in the pipes to be heated by the surrounding hot boiler water. Then the heated water is carried to the faucets and showers of the house.
Some advantages are that an immersion coil system allows free hot water in the winter time. Free hot water is available because the boiler is on anyway to heat the house. Sometimes immersion coils have valves to adjust the hot and cold mixture. The disadvantages are that an immersion coil system isn't as energy efficient as using a separate water heater in the summer months. Also, an immersion coil system adds an unwanted heat load on the house in the warmer months due to the boiler being on. Since the boiler has to operate all year round, it will cut down the life expectancy of the heating system. Furthermore, immersion coils can clog over time and need occasional cleaning due to the minerals in water.
Newer types of immersion coil systems are called indirect-fired water heaters. At first glance, indirect-fired units look like separate water heaters. However, indirect-fired units do not have burners to heat the water at the base of the tank. As a result, they last much longer than separate water heaters because there are no burners that deteriorate the tank. The immersion coils in the boiler have a circulator pump on them. This pumps the heated water from the boiler immersion coils to the storage tank. Since you're basically dealing with an immersion coil system, you have the disadvantage of operating the boiler in the summer.
Separate water heater units can be gas, oil or electrically heated. Review the furnace or boiler section on the differences between gas, oil and electrically operated heaters and the inspection process involved.
Oil fired water heaters have a very fast recovery rate. This refers to the rate at which they can reheat the water. On oil fired units there should be a water temperature setting switch. The purpose of this is to operate like a thermostat. Water temperature switches regulate the burners to turn on and off to keep the water at a preset temperature. The factory recommended setting is usually at 125-130 degrees Fahrenheit. If the temperature is set too high, then someone can get scalded with very hot water.
Gas fired water heaters usually have a dial type of temperature setting. You'll find the dial temperature switch located directly on the gas burner assembly near the bottom of the water heater tank.
Electrically operated water heaters have coils that are directly immersed in the water inside the tank. This is different from the oil and gas fired heaters. Oil and gas fired units heat the water holding tank and then the heat dissipates to the water inside the tank. Electric units usually aren't as energy efficient as gas or oil fired units. The reason for this is that electricity can be more expensive than the other fuels. Often you'll find electric water heaters in condos or in areas where gas service isn't available.
Electrically operated water heaters usually have two temperature setting dials inside the small cover plates on the side of the tank. Don't remove these panel covers due to the potential hazards of electricity. I once tried to remove the temperature setting cover on an electric water heater. There was a big spark as soon as I loosened the screw. The circuit breaker in the main electrical panel tripped off after this happened. When I removed the cover on the water heater, I found an exposed wire. Apparently the metal cover plate was installed too close to the temperature dial wires. This caused a small section of the wire insulation to be cut, leaving an exposed wire. We later found out that this water heater manufacturer recommends the circuit breaker be turned off before opening the temperature panel cover. I was certainly lucky that circuit breaker was working properly.