LAARS Mighty Stack MS-080 (Sizes 199, 300, 399) - Install and Operating Manual - Manual (Page 16)

Laars Heating Systems Page 16
SECTION 4.
Water Connections
4.1 Water System Piping
Pipe the outlet from the heater’s relief valves
such that any discharge from the 2 relief valves will be
conducted to a suitable place for disposal when relief
occurs. Do not reduce line size or install any valves in
this line. The lines must be installed to allow complete
drainage of both the valve and the line (see Figure 4).
The minimum inlet water temperature for the
Mighty Stack is 120°F (49°C) to avoid condensing on
the copper coils. It is the responsibility of the installer
to properly mix supply water as necessary to keep the
return water temperature above 120°F.
NOTE: Laars will not warranty claims for failure to
provide minimum return water temperature.
4.2 Hot Water Supply Piping
If the Mighty Stack water heater is installed in
a closed water supply system, such as one having a
backflow preventer in the cold water supply line, the
relief valve may discharge periodically, due to thermal
expansion. Means (such as a properly-sized expansion
tank) shall be provided to control thermal expansion.
Contact the water supplier or local plumbing inspector
on how to control this situation.
4.3 Water Flow Requirements
In a water heating application, new water is
constantly being introduced. With the new water
comes a fresh supply of minerals that can be deposited
on the unit’s heat exchanger. This is commonly known
as scaling. The amount of minerals will depend
upon the hardness of the water. Water can also be
aggressive, and can erode metals, including copper,
if the water is moved too quickly. The water flow
requirements for the Mighty Stack water heater are
based upon the hardness of the water. The water flow
is kept high enough to prevent scaling, but low enough
to prevent tube erosion. For extremely soft or hard
water, cupro-nickel tubes are available. Contact a
Laars representative if you have questions or concerns
about water quality.
Water heaters can be ordered with a standard
pump for soft or normal water or with a pump for
hard water. The pumps used are sized for the head loss
through the heater.
4.4 Combined Water Heating (potable)
and Space Heating
NOTE: These systems are not allowed in the
Commonwealth of Massachusetts.
Piping and components connected to this water
heater shall be suitable for use with potable water.
Toxic chemicals, such as used for water heater
treatment, shall not be introduced into the potable
water used for space heating.
This water heater shall not be connected to any
heating system or component(s) previously used with a
non-potable water heating appliance.
When the system requires water for heating at
temperatures higher than required for other uses,
an anti-scald mixing or tempering valve shall be
installed to temper the water for those uses in order
to reduce scald hazard potential.
4.5 Freeze Protection
Although Mighty Stack water heaters are design-
certified for outdoor installations, such installations
are not recommended in areas subject to freezing
temperatures, unless proper precautions are taken.
Power outage, interruption of gas supply, failure
of system components, activation of safety devices,
etc., may prevent a heater from firing. Any time a
heater is subjected to freezing conditions, and the
heater is not able to fire, and/or the water is not
able to circulate, there is a risk of freezing in the
heater 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 heater, which could
result in leaking or flooding conditions.
Contact the local factory representative or Laars
for additional information.