Navien LCB700-21LC Installation & Operation Manual Download

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Installing the System Piping 21

4.1 Installing a Central Heating System

The fire-tube type heat exchanger of the Navien LCB700 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

The installation must be made by sufficiently qualified
technicians, authorised to do so.

For correct installation, all the requirements and
recommendations described in the Regulation for
Heating Installations in Buildings (RITE) must be
complied with, together with all other national and/or
local regulations applicable at the time of installation.

Refer to the following illustration for a typical heating piping
example for the boiler.

CH Flow

CH Return

Heating Circuit

Heating

Supply

Valve

Adapter

Heating

Return

Valve

Adapter

<Regular, System Models - Right View>

CH Flow

CH Return

Heating Circuit

W F

DHW F

When connecting the central heating system, follow these
guidelines:

Tighten the connection valves with care to avoid damage.

Test the boiler for proper central heating flow and inspect for
leaks.

4.1.1 Guidelines for a Central Heating Installation

Read and follow the guidelines listed below to ensure safe and
proper installation of a boiler heating system.

Freeze Protection for a Central Heating System

Freeze protection products may be used for the central
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
35% 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.

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 LCB700 boiler is intended solely for use in
pressurised closed loop heating systems operating with 1-3
bar water pressure at the boiler outlet. To obtain the minimum
system design pressure, follow the piping diagrams illustrated
in this section.

The Navien LCB700 boiler’s central 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.

Air Elimination

This boiler may only be installed in a pressurised closed-loop
heating system, free of air and other impurities. To avoid the
presence of air, ensure all of the air is removed from the system
during commissioning via strategically placed and adequately
sized air removal devices 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 device in case an additional air removal
device is required for a specific application.