Navien NFB-175H, Installation Manual, Page: 18 / 135

18 Installing the System Piping
Prior to connecting piping to the boiler, flush the
entire system to ensure it is free of sediment, flux,
solder, scale, debris or other impurities that may
be harmful to the system and boiler. During the
assembly of the heating system, it is important
to keep the inside of the piping free of any debris
including construction dust, copper burr, sand and
dirt.
For retrofits, all system piping including radiators,
must be cleaned of all build-up including sludge
and scale. All systems, old and new, must be
cleaned to remove flux, grease and carbon residue.
Navien recommends cleaning the boiler system
with cleaning products specially formulated
for boiler systems. For retrofit applications with
heavy limescale and sludge deposits, a heavier
duty cleaner may be required. For information on
performing the cleaning, follow the instructions
included with the boiler system cleaner products.
WARNING
Failure to rid the heating system of the
contaminants listed above will void your
warranty and may result in premature heat
exchanger failure and property damage.
3.1 Installing a Space Heating
System
The fire-tube type heat exchanger of the Navien
NFB-H boiler is designed to attain the highest level
of heat transfer in a compact design. To accomplish
this, the heated gas flows through a series of small-
diameter tubes, maximizing the heat transfer area.
To maintain the efficient and reliable operation of
the heat exchanger, and to avoid heat exchanger
failure, it is critical to ensure the rules and guidelines
in this section are followed.
CAUTION
Failure to follow the instructions provided in this
section will void the warranty and may result in
property damage, fire, serious injury or death.
3.1.1 Guidelines for a Space Heating
Installation
Read and follow the guidelines listed below to
ensure safe and proper installation of a boiler
heating system.
Freeze Protection for a Space Heating
System
●
Freeze protection products may be used for the
space heating system. Freeze protection for new
or existing systems requires specially formulated
glycol, which contains inhibitors to prevent
the glycol from attacking the metallic system
components.
●
Before using freeze protection products,
ensure that system fluid contains proper
glycol concentration and the inhibitor level
is appropriate. Navien recommends against
exceeding a 50% concentration of glycol.
●
When using the freeze protection products, the
system must be tested at least once a year, and as
recommended by the manufacturer of the glycol
solution.
●
When using the freeze protection products,
allowance should be made for expansion of the
glycol solution.
●
Freeze damage is not covered by the warranty.
●
The use of glycol results in a greater head loss
due to its higher viscosity compared to water. See
page 24 for additional information regarding
the use of glycol.
WARNING
For systems requiring freeze protection, use only
inhibited propylene glycol, specially formulated
for hydronic heating systems; use of other types
of antifreeze may be harmful to the system and
will void the warranty.
3. Installing the System Piping