LAARS Pennant PNCV (Sizes 500-2000) - Install and Operating Manual - Manual (Page 20)

LAARS Heating Systems Page 20
SECTION 4B.
Water Connections —
Pennant Water Heater
4B.1 Water System Piping —
Water Heater
Hot water piping should be supported by suitable
hangers or floor stands. Do not support piping with
this appliance. Due to expansion and contraction of
copper pipe, consideration should be given to the type
of hangers used. Rigid hangers may transmit noise
through the system resulting from the piping sliding in
the hangers. It is recommended that padding be used
when rigid hangers are installed.
The Pennant can be used with several different
types of readily available storage tanks. A pump draws
water from the storage tank and pumps the water
through the heater and back into the tank. Pump-
mounted units have a circulating pump built into
the water heater. The pumps used are sized for the
headloss through the heater, plus 30 feet (9.1m) of full-
sized piping (same size as boiler outlet) and a normal
number of fittings. Pumps used on pump-mounted unit
are sized for soft/normal or hard water, so make sure
a pump-mounted unit matches the water quality of the
installation.
Pipe the outlet from the heater’s relief valve
such that any discharge from the relief valve 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 line must be installed to allow complete
drainage of both the valve and the line.
Suggested piping diagrams are shown in Figures
9 through 12. These diagrams are meant only as a
guide. Components required by local codes must be
properly installed.
Note the recommended location of the
temperature sensor on the diagrams. The Pennant is
shipped with an additional sensor that can be used for
more full-featured domestic water heating control. To
get these features, you must provide a location for the
additional sensor. It can be strapped to a pipe from 1"
to 4" diameter, or inserted into a tank immersion well.
The minimum inlet water temperature for the
Pennant is 120°F (49°C) to avoid condensing on the
copper coils.
4B.2 Hot Water Supply Piping —
Water Heater
Follow the tank manufacturer’s guidelines for
completion of the hot water system connections.
NOTE: A listed temperature and pressure relief
valve listed as complying with the Standard for
Relief Valves and Automatic Gas Shutoff Devices
for Hot Water Supply Systems (ANSI Z21.22 /
CSA 4.4) of suitable discharge capacity must be
installed in the separate storage tank system.
If the Pennant 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.
4B.3 Water Flow Requirements —
Water Heater
In a water heating application (an open system),
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 Pennant 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.
Pump-mounted water heaters can be ordered
with standard pumps for soft or normal water or with
pumps for hard water. The pumps used are sized for
the headloss through the heater, plus 30 feet (9.1m)
of full-sized piping (same size as heater outlet) and a
normal number of fittings.
Table 9 specifies water flow rates for water
heaters, which will enable the user to size a pump.
The headloss shown is for the heater only, and the user
will need to add the headloss of the piping system to
properly size the pump.
4B.4 Combined Water Heating (potable)
and Space Heating — Water Heater
NOTE: These systems are not allowed in the
Commonwealth of Massachusetts.
Piping and components connected to this water
heater for the space heating application shall be
suitable for use with potable water.
Toxic chemicals, such as used for boiler
treatment, shall not be introduced into the potable
water used for space heating.
This water heater when used to supply potable
water 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.