Bradford White LAARS OmniTherm ONH1250, Инструкция по установке и эксплуатации

Страница: 27 / 132

Page 27
The
O
MNI
T
HERM
SECTION 5
Piping
5.A Boiler Water Piping
in the heat exchanger and condensate inside and outside
of the boiler from freezing. Damage due to freezing water or
condensate is not covered by the warranty. The unit must
not be operated in conditions below 5F (-15C).
If installed outdoors, and there is an event such as
a power outage, interruption of gas supply, failure of
system components, activation of safety devices, etc.,
this may prevent a boiler from firing.
Any time a boiler
is subjected to freezing conditions, and the boiler
is not able to fire, and/or the water is not able to
circulate, there is a risk of freezing in the boiler or
in the pipes in the system.
When water freezes, it
expands. This may result in bursting of pipes, or damage
to the boiler, and this could result in leaking or flooding
conditions.
Do not use automotive antifreeze. To help prevent
freezing, The manufacturer recommends the use of
inhibited glycol concentrations between 20% and 35%
glycol. Typically, this concentration will serve as burst
protection for temperatures down to approximately -5°F
(-20°C). If temperatures are expected to be lower than
-5°F (-20°C), glycol concentrations up to 50% can be
used.
When concentrations greater than 35% are
used, water flow rates must be increased to maintain
the desired temperature rise through the boiler.
WARNING
Glycol must not be used in domestic hot water
applications. Refer to 5.B.4 on page 32 for
instructions on freeze protection for units (domestic hot
water).
Different glycol products may provide varying degrees
of protection. Glycol products must be maintained
properly in a heating system, or they may become
ineffective. Consult the glycol specifications, or the glycol
manufacturer, for information about specific products,
maintenance of solutions, and set up according to your
particular conditions.
The following manufacturers offer glycols, inhibitors,
and anti foamants that are suitable for use in the unit.
Please refer to the manufacturers instructions for proper
selection and application.
• Sentinel Performance Solutions Group
• Hercules Chemical Company
• Dow Chemical Company
The boiler control offers some assistance with freeze
protection, as long as the boiler is energized, and able to fire.
5.A.1 Boiler Water Connections
NOTE: This unit must be installed in a closed pressure
system with a minimum of 12 psi (82.7 kPa) static
pressure at the boiler.
The water piping should be supported by suitable
hangers or floor stands. Do not support the piping with
this unit. The hangers used should allow for expansion
and contraction of pipe. Rigid hangers may transmit
noise through the system resulting from the piping sliding
in the hangers. We recommend that padding be used
when rigid hangers are installed. Maintain 1” (2.5 cm)
clearance to combustibles for all hot water pipes.
Suggested piping diagrams are shown in Figure 4
through Figure 7. These diagrams are meant only as
guides. Components required by local codes must be
properly installed.
Pipe the discharge of the relief valve (full size) to a drain
or in a manner to prevent injury in the event of pressure
relief. Install an air purger, air vent, expansion tank,
hydronic flow check valve in the system supply loop, and
any other devices required by local codes. The minimum
fill pressure must be 12 psig (82.7 kPa). Install shutoff
valves where required by code.
5.A.2 Cold Water Make-Up
1. Connect the cold water supply to the inlet
connection of an automatic fill valve.
2. Install a suitable back flow preventer between the
automatic fill valve and the cold water supply.
3. Install shut off valves where required.
In some installations, a hot water heating boiler is
connected to heating coils located in an air handling
unit where the coils may be exposed to refrigerated air
circulation. In these cases, the boiler piping system must
be equipped with flow control valves or other automatic
means to prevent gravity circulation of the boiler water
during the cooling cycle.
A boiler installed above radiation level, or as required by
the authority having jurisdiction, must be provided with a
low water cutoff device either as a part of the boiler or at
the time of boiler installation.
5.A.3 Freeze Protection
This unit may be installed indoors or outdoors. If installing
outdoors in a location that may experience freezing
temperatures, precautions must be taken to prevent water