Water heaters are appliances or equipment that is designed to heat potable water and distribute it to the hot water system. Heated water expands and this can result in a potentially dangerous build-up of pressure in a tank-type water heater. Our engineers will recommend which type of hot water heater design will suit your needs, work best in your environment, and save energy at home or at work.
Water heaters are appliances or equipment that is designed to heat potable water and distribute it to the hot water system. There are several different types, primarily those that have storage tanks and those that don’t.
Low-pressure boilers may be used for heating and for the supply of hot water. They operate at water temperatures and pressures that are slightly higher than water heaters – specifically, 250 °F vs 210 °F and 160 pounds per square inch (psi) vs 150 psi.
Tank-type water heaters, also known as storage water heaters, are generally fueled by electric or solar power, propane or natural gas, or oil. But whatever the fuel or energy used, they operate in a similar way, with similar components including valves and various pipes and fittings that deal with overflow and pressure relief. Also, the internal tank is commonly wrapped with some type of insulating material that ensures the water stays hotter for longer.
Tanks are available in different sizes. Cold water is piped into the bottom of the tank to ensure it is always full. Water expands when it is heated causing internal pressure. While there are safety devices and mechanisms that engineers use in hot water heater design to counter the risks of pressure damage to the plumbing system, manufacturers of storage tanks and water heaters stamp them on the outside of the tank to show what the maximum allowable working pressure is. The stamp is in the form of an indelible mark in a position that will be accessible for inspection.
It stands to reason that tank-type water heaters and storage tanks must be located (and connected) so that they are accessible and there is sufficient space for maintenance, servicing, and replacement if required.
More energy-efficient than tank-type water heaters, tankless water heaters, which provide water on demand, may operate with natural gas or propane, or with electricity, with gas-fired models producing higher flow rates. Because they don’t result in the standby energy losses associated with storage water heaters, they save money. Instead, cold water is piped into the unit and an electric element or gas burner heats the water.
Homes that use no more than 41 gallons of hot water every day can increase their energy efficiency by 24% to 34% if they use tankless rather than water heaters with tanks. It is possible to increase energy efficiency by up to 50% by installing instantaneous water heaters at every hot water outlet in the house. Families that use more than double this amount of hot water daily (around 86 gallons a day) will find they can increase energy efficiency by at least 8% to 14%.
Another good reason to install multiple tankless hot water heaters is that one unit won’t have the capacity to operate with multiple appliances at the same time. So if you want to shower while you wash your clothes in a washing machine or clean your dishes in a dishwasher the flow rate of the water heater will be compromised.
The NYC Plumbing Code 2014 requires water temperature control in piping connected to tankless heaters. When installed for domestic use, the maximum temperature should be 140 °F or 60 °C.
In New York City (NYC) all electric water heaters must comply not only with the NYC Plumbing Code 2014 but also with the City’s Electrical Code.
If you are planning to install a water heater in an attic, the NYC Plumbing Code 2014 specifies that only electric water heaters are allowed. Installation requirements are also provided to ensure that there is sufficient space around the water heater. There must also be a passageway with solid flooring that is large enough to allow removal of the water heater.
Although solar water heaters are fueled quite literally by the sun, they are frequently designed with a backup system that uses electricity or another fuel, either in the form of a storage water heater or tankless water heater. There are two types, active systems that incorporate circulating pumps and controls, and passive types that don’t. All have solar collectors of some sort, either flat-plate collectors, integral collector-storage systems, or evacuated-tube solar collectors that feature parallel glass tubes. They also have either one or two tanks to store the hot water.
Heat pump water heaters also utilize electricity, but they are considerably more energy efficient than conventional electric hot water heaters. Heat pumps operate like refrigerators, but in reverse. Basically, the machine pulls heat from the air and transfers it to a water tank, in this way heating the water.
Both solar water heaters and heat pumps are more expensive than conventional storage heaters but their lower operating costs offset the initial purchase price.
Gas-fueled water heaters may be used instead of regular hot water supply, but only if certain requirements are met.
For instance, the NYC Building Code only allows their use in:
Additionally, gas-fueled water heaters must comply with the City’s Plumbing and Fuel Gas Codes. Amongst other things, they must be installed in an approved location and a sediment trap should be placed on the gas line into the water heater as close to the inlet as possible. This prevents debris and moisture from entering the hot water heater’s firing chamber.
Copper fin tube, gas-fired domestic hot water heaters require a flow switch that can be used to interrupt the supply of gas to the heater if water flow through the coil is temporarily stopped.
The other important factor is that gas water heaters must be correctly vented to prevent CO2from getting into your home. The vent system must be designed professionally in accordance with local codes.
In NYC, oil-fired water heaters must conform to the requirements of the City’s Mechanical and Plumbing Codes.
Like gas-fired hot water heaters, oil-fired heaters rely on fuel lines and a venting system that will remove exhaust gases. Like traditional gas-fired and electric water heaters, they have tanks where the water is stored. While they aren’t fueled by electricity, like some gas models, oil-fired water heaters utilize an electric spark to get them started.
Relatively expensive to buy, oil-fired water heaters are incredibly energy-efficient and the time it takes to heat the water can by as much as four times faster than other types of heaters. The tanks can also store a considerably higher volume of hot water.
