LAARS MagnaTherm MGV - Installation, Operation and Maintenance Instructions - Manual (Page 23)

MagnaTherm Boilers and Water Heaters Page 19
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.
6.3 MGH Freeze Protection
MagnaTherm units may be installed indoors or
outdoors. If installing outdoors in a location that
may experience freezing temperatures, precautions
must be taken to prevent water 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.
If installed indoors, 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, LAARS 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 a 20°F to 25°F temperature
rise through the boiler.
WARNING
Glycol must not be used in domestic hot
water applications. Refer to Section 7 for
instructions on freeze protection for MGV
units (domestic hot water).
Section 6 -
WATER CONNECTIONS
MGH BOILERS
6.1 MGH System Piping:
Hot Supply Connections
Note -
This appliance must be installed in a closed
pressure system with a minimum of 12 psi (82.7
kPa) static pressure at the boiler.
The hot water piping should be supported by
suitable hangers or floor stands. Do not support the
piping with this appliance. 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.
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, an air vent, an
expansion tank, a 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.
Suggested piping diagrams are shown in Figure 7
through Figure 10. These diagrams are meant only as
guides. Components required by local codes must be
properly installed.
The MagnaTherm’s efficiency is higher with
lower return water temperatures. Therefore, to
get the best low return temperature with multiple
boilers, pipe as shown in Figure 9 and Figure 10.
6.2 MGH 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
appliance 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.