LAARS Mighty Therm LO-NOx PH (Sizes 250/400) - Install and Operating Manual - Manual (Page 12)

LAARS Heating Systems
Page 12
across the boiler when the is mixture is used, increase
the water flow by 15% above the original
recommendation. Increase the head loss requirement
by 20%.
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.
2.6.2 Pump Requirements
High recovery, low volume water boilers need
enough water flow for efficient operation. The system
pump must develop enough pressure to overcome the
pressure drop of the boiler plus the pressure drop of
the entire circulation system at the flow rates selected
from Table 3.
The correct flow rate can be verified by checking
the temperature rise of water as it passes through the
boiler. To check the temperature rise, measure the
difference in water temperature between the boiler
inlet and outlet to determine flow. For example: If a
Size 250 boiler is installed; the inlet water temperature
is 160°F (71°C); and the outlet water temperature is
185°F (85°C); then there is a 25°F (14°C) temperature
rise. Per Table 3 this equals a flow rate of 16 GPM
(1.0L/s) and a head loss (pressure drop) of 1.2 feet of
water. If a higher temperature rise is measured, flow
section du système d’évacuation doit être
modifiée, le système devrait être modifié pour
respecter les valeurs minimales des tableaux
pertinents de l’appendices F du National Fuel
Gas Code, ANSI Z2231.1 et (ou) des codes
d}installation CSA-B149.1.
2.6 Water Flow System
2.6.1 Freeze Protection
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. This can result in bursting of pipes in the
system, or damage to the boiler, which could result in
leaking or flooding conditions.
Do not use automotive anti-freeze. Maintaining a
mixture of minimum 50% water and maximum 50%
properly inhibited HVAC glycol, which contains an
antifoamant, is the preferred method of freeze
protection for Mighty Therm boilers. Percentage of
glycol used in the Mighty Therm boiler must not
exceed 50%. Typically, this mixture will serve as burst
protection for temperatures down to approximately
-35°F (-30°C). To get the desired temperature rise
Figure 22. Multiple Boilers, Primary Secondary Sytem.
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