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15
Solar Installation
If this water heater is used as a solar storage heater or
as a backup for the solar system, the water supply
temperatures to the water heater tank may be in excess
of 120°F. A tempering valve or other temperature limiting
valve must be installed in the water supply line to limit the
supply temperature to 120°F.
Note: Solar water heating systems can often supply water
with temperatures exceeding 180°F and may result in
water heater malfunction.
IMPORTANT: Water supply to this heater must not
exceed 180°F. Water temperature in excess of 180°F
will cause the High Limit Control to open and shut off the
gas supply to the unit. The High Limit Control is a single
use type that will require the replacement of the thermostat
before the burner will operate.
Special Applications
Combination Space Heating/ Potable
Water System
Some water heater models are equipped with inlet/outlet
tappings for use with space heating applications. If this
water heater is to be used to supply both space heating
and domestic potable (drinking) water, the instructions
listed below must be followed.
· Be sure to follow the manual(s) shipped with the
air handler system.
· This water heater is not to be used as a
replacement for an existing boiler installation.
· Do not use with piping that has been treated with
chromates, boiler seal or other chemicals and do
not add any chemicals to the water heater piping.
· If the space heating system requires water
temperatures in excess of 120°F, a tempering
valve or an anti-scald device should be installed
per its manufacturers instructions in the domestic
(potable) hot water supply to limit the risk of scald
injury.
· Pumps, valves, piping and fittings must be
compatible with potable water.
· A properly installed flow control valve is required
to prevent thermosiphoning. Thermosiphoning is
the result of a continuous flow of water through
the air handler circuit during the off cycle. Weeping
(blow off) of the temperature and pressure relief
valve (T & P) or higher than normal water
temperatures are the first signs of thermosiphoning.
· The domestic hot water line from the water heater
should be vertical past any tempering valve or
supply line to the air handler to remove air
bubbles from the system. Otherwise, these bubbles
will be trapped in the air handler heat exchanger
coil, reducing the efficiency.
· Do not connect the water heater to any system or
components previously used with non-potable
water heating appliances when used to supply
potable water.
Some jurisdictions may require a backflow preventer in
the incoming cold water line. This may cause the
temperature and pressure relief valve on the water
heater to discharge or weep due to expansion of the
heated water. A diaphragm-type expansion tank suitable
for potable water will normally eliminate this weeping
condition. Please read and follow the manufacturers
instructions for the installation of such tanks.
Also see Water System Piping (Page 12) for additional
instructions on the safe and correct installation and
operation of this water heater.
Coil
Must Be Vertical To Remove
Air Bubbles
Domestic
Hot Water
Out
Tempering
Valve
Hot
Water
Out
Unions
Cold
Water
Inlet
Pump
Flow Control
Valve
To
Air
Handler
Shut Off Valve
Out
In
Air
Handler
Typical tempering valve
installation Combination space
heating/ potable water heating system
Massachusetts Code
does not allow this type
of installation.
Figure 15: Space Heating Piping Installation