A.O. Smith PHPT-80 Condensate Drain Line Installation, Closed System/Thermal Expansion

Please note the following:

•The system should be installed only with piping that is suitable for potable (drinkable) water such as copper, CPVC, or polybutylene. This water heater must not be installed using iron piping or PVC water piping.

•Use only pumps, valves, or fittings that are compatible with potable water.

•Use only full flow ball or gate valves. The use of valves that may cause excessive restriction to water flow is not recommended.

•Use only 95/5 tin-antimony or other equivalent solder. Any lead based solder must not be used.

•Piping that has been treated with chromates, boiler seal, or other chemicals must not be used.

•Chemicals that may contaminate the potable water supply must not be added to the piping system.

Condensate Drain Line Installation

Install two 1/2” PVC discharge lines from the condensate drains (located on the right side near the back). The lines should terminate a maximum of six inches above an adequate drain. Do not discharge the condensate drain lines into the metal drain pan. If no floor drain is available or the drain is above the level of the condensate line, a condensate pump should be installed. These pumps are available from local distributors.

When installing the drain line, note the following:

•Plastic pipe or tubing must be used to connect the condensate drain to a suitable drain or condensate pump.

•Condensate drain lines should be installed in conditioned areas only. Install approved insulation on the condensate drain lines to prevent condensation from forming on the outside of the drain lines. Condensation drain lines installed in areas that are subject to freezing temperatures should be wrapped with a nationally recognized/listed heat tape. Install per manufacturer’s instructions.

•Do not connect condensate drain lines with other drain or discharge lines into a single (common) pipe or line. Each line (condensate drain line, temperature and pressure relief valve discharge pipe, etc) should be independently run to an adequate drain.

•Slope the condensate drain lines toward the inside floor drain or condensate pump.

•The condensate drain lines and connections to the drain piping must comply with all local codes.

•Use appropriate primer and glue to cement the condensate drain lines to the heat pump drain pan. NOTE: The heat pump drain pan is ABS and the two condensate drain pipes should be PVC.

•If a condensate pump is installed it should shut off the heat pump in the event the condensate pump fails or the float switch in the pump activates (See “Condensate Pump Installation” section.)

Closed System/Thermal Expansion

WARNING

Explosion Hazard

If the temperature and pressure relief valve is dripping or leaking, have a qualified person replace it.

Examples of a qualified person include: licensed plumbers, authorized electric company personnel, and authorized service personnel.

Do not plug valve. Do not remove valve.

Failure to follow these instructions can result in death or explosion.

Most public water systems in North America are required to prevent water flowing from points of use (residences, businesses, etc.) back into the supply system in order to maintain water quality. To accomplish this, back flow preventers such as check valves, are installed in the water line going to each point of use. Typically the back flow preventer will be installed at the water meter or inside a building where the supply line enters the building. This device allows water to flow into the residence but does not allow it to flow back into the water supply. This creates what is known as a “Closed System”. As water is heated by the water heater, the water in the system attempts to expand, but has nowhere to go resulting in an increase in pressure. This increase in pressure in the system may cause the temperature-pressure relief valve to open to relieve the pressure. Water will drip from the temperature and pressure relief valve. Premature tank failure will result

if this condition is not corrected. To prevent this condition, a properly-sized thermal expansion tank should be installed in the cold water supply to the water heater as shown in Figure 4. Failure to install a properly sized expansion tank in a closed system will void the warranty on the water heater in the event of tank failure. It is important to follow the thermal expansion tank manufacturers’ installation instructions and to adjust the expansion tank pressure

to match the water supply pressure. Contact a plumbing service agency or your retail supplier regarding the installation of a thermal expansion tank.

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