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8.3 Freeze Protection
FT Series Boilers 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.
NOTICE
Not all pumps are capable of maintaining the reduced
temperature rise required with glycol concentrations
greater than 35%.
NOTICE
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.
Some items to consider are
• Consider the effects of reduced heat transfer and
an increase in head pressure against the system
circulator. For example: A 30% mixture of glycol will
result in a BTU output loss of 15% with a 5% increase
in head against the system circulator.
• Glycol mixtures should not exceed 50%. A 50%
mixture of glycol will result in a BTU output loss of
30% with a 50% increase in head against the system
circulator.
• The glycol solution should be tested as
recommended by the glycol manufacturer but not less
than annually. Some items of concern are pH additive
breakdown, inhibitor reduction, etc.
• Glycol/antifreeze solutions expand more than water;
therefore, system design must take this into account.
For example: a 50% by volume solution expands
4.8% in volume for a temperature increase from 32◦F
to 180◦F, while water expands 3% over the same
temperature rise.
Do NOT use automotive antifreeze or ethylene
glycol. Use only inhibited propylene glycol
solutions which are specially formulated for
hydronic systems. Ethylene glycol is toxic
and can attack gaskets, seals, and metallic
components used in hydronic systems. A
correct glycol concentration and inhibitor level
is critical.
WARNING
Caution
It is highly recommended to follow the manufacturers
recommended concentrations, expansion requirements,
and maintenance recommendations. You must carefully
calculate the additional friction loss in the system as well
as the reduction in the heat transfer coefficients.
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