Installing a tankless water heater - basics. Find out how to
install Rinnai, Noritz, Takagi and other water heaters, tips
article is for homeowners who are planning to install a tankless water
heater. If you experience any problem during or after the installation,
or have questions regarding the unit, the best will be to call a
representative for that particular brand.
What's must to do when
installing a tankless water heater
Installing a tankless water heater shouldn't be complicated
and unsafe, as long as you follow all the codes, local and national,
and manufacturer's instructions, found on the rating plate and manual.
heaters are safe for the installation
literally anywhere inside your home. They are designed with a sealed
combustion with zero clearance to combustibles. Even with the increased
safety, choosing the right location for powervent, direct vent models
included, is very important step.
Avoid rooms where chemicals, gasoline and materials than
can produce the flammable vapors are stored.
Avoid rooms that might contain an excessive amount of dirt,
dust, aerosols and other debris, which can clog the air vent, reduce
the fan efficiency or damage the heater.
Install a tankless water heater so it provides enough space
future service and maintenance.
Water heater designed for the outdoors should be installed
only outside, in areas with the mild climates and preferable in the
Avoid installing a unit in an attic due to safety issues.
For the tankless installations at the higher elevation than
contact the manufacturer to confirm this application.
You can install a tankless water heater in the mobile or
manufacturing homes, only if it is certified for this application.
When installing a tankless water heater, either Noritz,
any other brand, see the model description on the
rating plate and read the manufacturer's instruction before
installation. The rating plate carries information such as the gas
type, electric rating, gas and water pressure. The type of gas has to
match the rating plate, and the gas pressure should be within the
specified range. If the pressure is below the minimum required,
the heater won't perform properly. If the pressure is higher
maximum allowed it can cause serious problems to the heater,
property and put you in danger.
Manual gas shut-off should be install between the gas
supply pipe and the heater.
Once the gas connection is completed and the air is purged
from the gas pipes, check for the gas leaks by using the soap-water
Check the inlet gas pressure by using the manometer, if
The gas manifold pressure is factory set, so no adjustment is
Install a tankless water heater where leakage won't
damage your property. A drain pan under the heater is recommended as a
way to protect the property against the water damage.
All tankless water heaters mentioned here, are designed for
potable water heating where the recommended supply pressure is
usually between 30 and 80 PSI and water connections are 3/4".
A manual shut-off valve should be installed between the
cold water supply and the heater. This type of valve can also be
installed on the hot water side.
Install the thermal expansion tank if the water system is
closed loop system.
Do not reverse the cold inlet and hot outlet connections.
Before installing a tankless water heater, flush the unit
and purge all the air from water pipes.
Install a pressure relief valve with the discharge pipe.
Minimum water flow/pressure should be provided for proper
Hot water heater temperatures are usually factory set on
The tankless water heaters are not suitable for
installation where the chemically treated water is used, such as spas
Follow the electric code requirements.
Tankless water heater must be grounded.
Install the remote controller if it is not provided.
Most of the tankless heaters are equipped with the
freeze protection system that requires an electrical power to the unit.
When installing a tankless water heater (US and Canada)
keep in mind to check out the electrical specs from the manufacturer's
instructions: i.e Rinnai requires 120 VAC and 60 Hz from the properly
Install a water heater as close as possible to the vent
The vent pipe must be easily removable and used only for
Avoid long runs of the vent pipe.
The vent terminator should never be blocked. In a case of
the vertical run, through the roof, the vent has to have a rain cap.
Avoid dips and sags.
Your tankless water heater must have enough fresh air for
the proper combustion and proper ventilation of the flue gases. Use the
recommended material and vent size, with no changes in diameter.
The vent system must be sealed air tight to prevent any
The exhaust vent should never point into any opening in a
building, such as windows or doors or near any air intake devices.
Leave the proper clearances between the water heater and
Keep in mind that installation of a tankless water heater
should be done correctly to ensures the safe and reliable water heating
and valid warranty. Regular maintenance which includes cleaning, visual
inspection and small service and replacement should be performed as
written in the instructions.