Bradford White BLMC125NA - Manual (Page 18)

Page 16 Bradford White Corp.
The boiler piping system of a hot water heating
boiler connected to heating coils located in air handling
appliances where they may be exposed to refrigerated
air circulation, 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 at the time of
boiler installation.
6.3 Freeze Protection
Brute Elite units are certified for indoor use only,
and are not design-certified for placement outdoors.
Proper precautions for freeze protection are
recommended for boiler installations in areas where the
danger of freezing exists.
Power outage, interruption of gas supply, failure
of system components, activation of safety devices, etc.,
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 which
may result in bursting of pipes, or damage to the boiler,
which could result in leaking or flooding conditions.
Do not use automotive antifreeze or ethylene
glycol. To help prevent freezing, Bradford White
recommends the use of inhibited propylene 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. NOTE:
Bradford White supplied pumps are not all capable
of maintaining the reduced temperature rise required
with glycol concentrations greater than 35%.
IMPORTANT NOTES: 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.
6.4 Suggested Piping Schematics
Figures 13 through 19 show suggested piping
configurations for Brute Elite boilers. These diagrams
are only meant as a guide. All components or piping
required by local code must be installed.
Figure 13. Hydronic Piping — High and low temp zones with indirect water heater (BLMH using internal 3-way).