Gas Tankless Water Heaters and their Installation Requirements

Gas Tankless Water Heaters and their Installation Requirements
January 24, 2013 Lorelie
gas tankless water heaters

Gas tankless water heaters have been around for a very long time, some saying since the turn of the nineteenth century

The early models were basically made of copper tubing along with a gas fire underneath it.  Although early models were very effective in heating water, they were sadly not very efficient in transforming the heat of the blaze into hot water.  They were also riddled with safety problems as they lack any type of safety controls.

In the U.S., the storage tank water heater became popular with households because they were affordable and relatively safe.  In addition, they did not require large gas lines to fuel their fire.  While storage tank-type water heaters are highly popular in the United States, the rest of the world looked into tankless-types water heaters, refined them and improved their overall efficiency.  For this very reason, gas-fired tankless water heaters are becoming the water heater of choice by many all across the world.

The tankless water heaters that are available today are equipped with a stainless steel heat exchanger.  Technological advancements have also been infused on these water heating units as they are now equipped with computer technology that controls and adjusts the flames of the unit via the variable gas burner to get the most out of the heat of the flames into the water.  This overall makes them very efficient.  In addition, since tankless-types water heating units do not need to preheat water and store them on storage tanks, they do not suffer from any standby heat loss.  Also, they do not consume fuel when not in use.  The best part about tankless units is that you do not need to worry about running out of heated water.  This is possible because water is being heated instantaneously, which means you have an unlimited supply of hot water.

Tankless water heating units come in different sizes – basically a visual projection on how much hot water it can produce as a small unit will never be able to project the same flow rate as that of bigger units.  A typical unit is able to generate roughly 8.5 gallons of hot water per minute, while the average showerhead uses only around 2.5 gallons per minute.  This gives the tankless water heater enough hot water to supply to at least 2 other hot water taps.

There are a few drawbacks to using tankless water heaters though.  One of the main drawback is that it takes several seconds before water gets into its optimum hot water temperature.  This means that if you want to take a shower, you need to wait several seconds for the unit to reach optimum heating levels before hot water leaves the showerhead.  If you try to shower early, you are likely to soak yourself in cold water.  Nevertheless, after the unit reaches optimum working temperature, you will be rewarded with unlimited supply of hot water.  Another drawback with gas-fired tankless water heaters is that they require a much bigger gas line which is why installing the unit yourself is not recommended unless you really know what you are doing, or are confident enough with your DIY skills.

Installation Requirements for Gas-fired Tankless Water Heaters

The installation of gas-fired tankless water heater is not as easy as it seems as it requires not just the necessary materials for installation, but also the corresponding permits.  The reason there is a need for permits is because the improper installation of the unit may lead to injuries, damage to properties, and even death.  This is why local city governments are strict about this.  The list below shows some of the requirements when installing gas-fired tankless water heaters:

Building Permit – these are needed when installing a new tankless unit, or replacing an old water heating unit with a new tankless model.  Check with your local municipality regarding building codes and permit.  If you are hiring a contractor to do the installation for you, you can ask them to secure the permit for you.  In a way, the permit acts as a safety guarantee as this helps ensure the safe proper installation of gas-fired appliances.

Temperature Relief Valve – when installing this to your newly affixed gas-fired tankless unit, make sure that the discharge from this component is directed at a safe location.  For uniformity, certain building codes require that the temperature relief valve is installed above 6 inches from the ground and no higher than 24 inches.  Most local building codes require that the discharged is piped outside of the building or structure.

Flue and Vent System – since this is a gas-fired unit, it is important that it has a properly installed flue and venting system so that no combustible fumes leak inside the home.  This is because these fumes can be fatal when exposed to for prolonged periods.  The flue and vent system should have good clearance on combustible materials.  There are proper materials that need to be used when installing flue and vent systems so make sure to use the one required by your water heater manufacturer.

Air Combustion – fire will not burn without access to oxygen.  This means that without access to oxygen, the burners inside the water heating unit will not light up, or if it does not have enough air, it will not be able to combust the gas properly.  Most gas-fired tankless water heating units require 20 square inches of combustion air in order to work properly.

Flexible Connectors – these are essential for earthquake prone areas as the flexibility of the gas supply connectors will ensure that they only bend with the flow of the earthquake and not get damaged in the process.  When installing flexible connectors, it is essential that you check for any leaks after installation so that unnecessary gas-leakage-related accidents do not occur.  As a safety precaution, never test gas-leakage with a match or an open flame.

Gas Pipe Inlet Size – most gas-fired tankless water heating units require a ¾ inch gas pipe.  If the unit does not have enough gas supply, it will not be able to operate under optimum conditions.  Gas pipes sometimes needs to be upgraded because some residential gas lines are too small to accommodate the tankless unit.

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