INSTALLATION INSTRUCTION - SUPPLEMENT SHEET
HEATING WITH THE SOLAR WATER HEATER WITH GAS BACKUP
POTABLE AND SOLAR HEATING CONNECTIONS
The heat exchanger interior has been designed for non-potable water, such as in a solar heating system. If
replacing an existing water heating appliance, be sure to turn off electrical power, heating fluid and/or gas
supply to the existing appliance.
The solar thermal system connections are identified on the side of the appliance. The use of shut off valves and
unions are recommended for future service convenience. In solar heating systems that are non-drainback, a
suitable expansion tank must be installed. Consult local codes for proper use, sizing and installation of an
expansion tank.
thermal expansion.
Due to the elevated operating temperature that may be obtained with the solar heating system, an ASSE
approved thermostatic mixing valve has been provided and must be installed in the potable water piping
diagram as shown in Figure 1. Directions for proper installation and adjustment are provided in the ASSE
approved thermostatic mixing valve carton.
Warning: Failure to properly install and regulate the provided ASSE approved thermostatic mixing valve may
increase the danger of scald injury and nullify the warranty.
Hotter water increases the risk of scald injury. Scalding may occur within 5 seconds at a setting of 140°F. Water
temperature over 125°F can cause severe burns or death from scalds. Children, disabled and the elderly are at the
highest risk of being scalded. Please feel the water before bathing or showering.
DO NOT operate this water heater in a closed system without provisions for controlling
DANGER
VACUUM BREAKER
SHUT-OFF VALVE
COLD
SUPPLY
THERMOSTATIC
MIXING VALVE
TEMPERED
POTABLE
Figure 1 – Thermostatic Mixing Valve Piping Diagram for Tempered Water
238-47632-00B REV 09/09
SOLAR HEATING WITH A CLOSED, FILLED SYSTEM
1) Pipe the system as shown in figure 2.
2) Install a properly sized expansion tank. An air separator and vent is recommended to eliminate air in
the system. The pressure relief valve should be piped to discharge within 6” from the floor.
3) A pressure reducing valve is recommended for installation to maintain appropriate pressure in the
closed loop system.
4) The circulator should be installed to pump away from the expansion tank as shown.
5) Purge all air from the filled, closed system.
TEMPERATURE AND
PRESSURE GAUGE
UNION
FULL PORT
BALL VALVE
"FROM SOLAR
COLLECTOR"
"TO SOLAR
COLLECTOR"
FULL PORT
BALL VALVE
UNION
AIR VENT
AIR SEPARATOR
PRESSURE RELIEF
VALVE (30 PSI)
EXPANSION
TANK
DRAIN VALVE
TEMPERATURE AND
PRESSURE GAUGE
DRAIN
VALVE
CIRCULATOR
FLOW CONTROL
VALVE
COLD WATER
PRESSURE
REDUCING VALVE
SUPPLY
SHUT OFF
VALVE
Figure 2 – Solar Heating with a Filled, Closed System
SOLAR HEATING WITH A DRAINBACK SYSTEM
1) Pipe the system as shown in Figure 3.
2) The pump should be installed to pump away from the lower heat exchanger connection.
3) Verify that all check valves are removed from the system and that all horizontal piping has at least a
1/4” per foot slope.
4) Fill the system until the water level is observed in the sight glass.
VENTIN
VALV
DRAINBAC
TANK
UNION
UNION
FULL PORT
BALL VALVE
SIGH
GLAS
SHUT OFF
VALV
COLD
WATE
SUPPL
FULL PORT
BALL VALVE
CIRCULATO
DRAI
VALV
Figure 3 – Solar Heating with a Drainback System
Heat Exchanger Specifications
Heat Ex ch anger Pre ssu re Drop Curve
7.00
6.00
5.00
4.00
3.00
(PSID)
2.00
Total Pressure Drop
1.00
0.00
01234567891011121314
Flowrate (GPM)
16.00
14.00
12.00
10.00
8.00
6.00
4.00
2.00
0.00
DOUBLE-WALL HEAT EXCHANGER – The solar water heater has a double-wall heat exchanger with a
slight gap between the two tubes that makes up the heat exchanger coil. The ¾” female fitting provides an
atmospheric vent for any fluid that enters the gap between the tubes. The heat exchanger has 14.2 ft
2
of heat
transfer surface area.
SENSOR WIRES FOR SOLAR THERMISTOR CONNECTIONS – Twisted wires are provided under the
lower and upper covers. These wires have been provided as a means for connecting thermistors to a solar
controller. NOTICE: Neither the solar controller nor the thermistors are provided with the solar water
heater and must be purchased separately. The lower thermistor wires connect a thermistor for use in
comparison to the solar collector temperature to determine if an appropriate temperature difference for heat
transfer is available. A bracket to fix the thermistor against the tank wall is supplied. The upper thermistor
wires are an optional second thermistor connection to monitor the upper tank temperature. Some solar
controllers provide this option.
ORANGE WIRE
WIRE NUTS
WIRE NUTS
BROWN WIRE
Head Loss(Feet)
Total
THERMISTOR
(NOT INCLUDED)
SENSOR PLATE
BRACKET
COVER
OPENIN
THERMISTOR
(NOT INCLUDED)
SENSOR PLATE
BRACKET
3/4" 3/4" SPUD
COVER
OPENING
NOTES
NOTES
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