State Industries GP650HTPDT, SHE50-100PE, SHE50-100NE manual Closed Water Systems, Thermal Expansion

ULTRA HIGH EFFICIENCY POWER VENT/POWER DIRECT VENT - SERVICE MANUAL

INSTALLATION CONSIDERATIONS

INSTRUCTION MANUAL

Installation information given in this Service Manual is not a complete installation instruction. Installation information covered in this Service Manual has a limited focus as it applies to servicing. This Service Manual does not replace or supersede the Instruction Manual that came with the water heater. Always refer to the Instruction Manual that came with the water heater for complete installation instructions.

If the instruction Manual that came with the water heater is not on hand copies can be obtained from the manufacturers web site or by calling the technical support phone number shown on the water heater labeling.

CLOSED WATER SYSTEMS

Water supply systems may, because of code requirements or such conditions as high line pressure, among others, have installed devices such as pressure reducing valves, check valves, and back flow preventers. Devices such as these cause the water system to be a closed system.

Virtually all commercial and most residential water supply systems are closed systems today. Closed water systems will experience thermal expansion which, if not controlled with a properly installed and sized thermal expansion tank, can cause premature failure (leakage) of the water heater. Water heater failure (leakage) on closed systems where there is not a thermal expansion tank installed is not covered under the limited warranty.

THERMAL EXPANSION

As water is heated, it expands (thermal expansion). In a closed system the volume of water will grow when it is heated. As the volume of water grows there will be a corresponding increase in water pressure due to thermal expansion. Thermal expansion can cause premature tank failure (leakage). This type of failure is not covered under the limited warranty. Thermal expansion can also cause intermittent temperature-pressure relief valve operation: water discharged from the valve due to excessive pressure build up. This condition is not covered under the limited warranty. The temperature-pressure relief valve is not intended for the constant relief of thermal expansion.

A properly sized thermal expansion tank should be installed on all closed systems to control the harmful effects of thermal expansion.

Technical Literature Department	4 of 52	Ashland City, TN © 2008
Servicing should only be performed by a Qualified Service Agent