![background image](http://html2.mh-extra.com/html/navien/nfc-250-175h/nfc-250-175h_installation-manual_3727065021.webp)
21
Installing the System Piping
Oxygen Elimination
This boiler may only be installed in a pressurized
closed-loop heating system, free of air (oxygen)
and other impurities. All of the air should be
removed from the system during commissioning
via strategically placed and adequately sized air
removal appliances, located throughout the heating
system.
Note
See the examples of system application
at the end of this section detailing the
installation location of the air removal
appliances, in case an additional air
removal appliances is required for a
specific application.
WARNING
●
Immediately repair any leaks in the system
piping to avoid adding make-up water.
Make-up water adds oxygen and minerals to
the system that may lead to heat exchanger
failure.
●
Failure to follow these instructions may result
in poor performance, unnecessary wear of
system components and premature failure.
CAUTION
Do not solder piping directly onto the water
connections, as the heat may cause damage
to internal components. Use threaded water
connections only.
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.
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.
System Pressure
●
The Navien NFC-H boiler is intended solely for
use in pressurized closed loop heating systems
operating with 12-80 psi water pressure at the
boiler outlet. To obtain the minimum system
design pressure, follow the piping diagrams
illustrated in this section.
●
The Navien NFC-H boiler’s space heating system
is not approved for operation in an “open system”,
thus it cannot be used for direct potable water
heating or to process heating of any kind.
Содержание NFC-250/175H
Страница 67: ...67 Venting for Combustion Air WARNING The vent installation detector Detectable Undetectable...
Страница 149: ...Memo...
Страница 150: ......