THERMAL EXPANSION
WARNING:The water heater should not be installed in a space where liquids which give off flammable vapors are to be used or stored.
Determine if a check valve exists in the inlet water line. It may have been installed in the cold water line as a separate backflow preventer, or it may be part of a
A cold water inlet line with no check valve or backflow prevention device is referred to as an “open” water system.
As water is heated, it expands in volume and creates an increase in the pressure within the water system. This action is referred to as “thermal expansion.” In an “open” water system, expanding water which exceeds the
WATER SUPPLY CONNECTIONS
Refer to the illustration below for suggested typical installation. The installation of unions or flexible copper connectors is recommended on the hot and cold water connections so that the water heater may be easily disconnected for servicing if necessary. The HOT and COLD water connections are clearly marked and are 3/4" NPT on all models.
NOTE:Install a
IMPORTANT: Do not apply heat to the HOT or COLD water connections. If sweat connections are used, sweat tubing to adapter before fitting the adapter to the cold water connections on heater. Any heat applied to the hot or cold water connection will permanently damage the dip tube.
TYPICAL INSTALLATION
capacity of the water heater flows back into the city main where the pressure is easily dissipated.
A “closed water system,” however, prevents the expanding water from flowing back into the main supply line, and the result of “thermal expansion” can create a rapid and dangerous pressure increase in the water heater and system piping. This rapid pressure increase can quickly reach the safety setting of the relief valve, causing it to operate during each heating cycle. Thermal expansion, and the resulting rapid and repeated expansion and contraction of components in the water heater and piping system, can cause premature failure of the relief valve, and possibly the heater itself. Replacing the relief valve will not correct the problem!
The suggested method of controlling thermal expansion is to install an expansion tank in the cold water line between the water heater and the check valve (refer to the illustration on right). The expansion tank is designed with an air cushion built in that compresses as the system pressure increases, thereby relieving the
To electrical 
distribution panel
Union 
Heat trap 
6" minimum 
Hot water 
outlet to fixtures
Temperature and 
Relief valve discharge line to suitable open drain
6" air gap 
Union | Heat trap |
| |
| 6" minimum |
To cold
water supply
Thermal expansion tank (if required)
Electrical junction box (use only copper conductors)
Jacket access panel
Jacket access panel
Auxiliary catch pan 2" 
maximum
Drain valve
CONDENSATION DRAIN TUBES
This unit has a condensation tray. The water collected in the tray drains out of the tube coming off the back of the unit. Two flexible hoses are included with this unit. It is important that both of these hoses are attached to the two drain ports coming off the back of the unit. Attach one end of the longer 6' hose to the lower drain port on the back of the unit, underneath the rear cover. Direct the
other end to a drain in the floor or no higher than 3' above the floor. If such
drain is unavailable, a condensate drain pump (not provided) must be purchased and installed. Attach the shorter 3" hose to the top drain port.
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