A.O. Smith GPDT, GPDX Closed Water System, Gas Connections, RELIEF VALVE P- See FIGURE, Venting

CLOSED WATER SYSTEM

A closed system will exist if a back-flow preventer (check valve), pressure reducing valve, or other similar device is installed in the cold water line between the water heater and the street main (or well). Excessive pressure may develop due to the thermal expansion of heated water causing premature tank failure or intermittent relief valve operation. This type of failure is not covered by the limited warranty. An expansion tank may be necessary in the cold water supply to alleviate this situation, see Figure 1. Contact the local plumbing authority.

If the temperature and pressure relief valve on the appliance discharges periodically, this may be due to thermal expansion in a closed water supply system. Contact the water supplier or local plumbing inspector on how to correct the situation. Do not plug the temperature and pressure relief valve.

GAS CONNECTIONS

The minimum gas supply pressure for input adjustment is 5.0" W.C. (1.25 kPa) for natural gas 11.0" W.C. (2.74 kPa) for propane.

THE HEATER IS NOT INTENDED FOR OPERATION AT HIGHER THAN 10.5" (2.6 kPa) FOR NATURAL & 13.0" (3.24 kPa) FOR PROPANE WATER COLUMN SUPPLY PRESSURE. EXPOSURE TO HIGHER GAS SUPPLY PRESSURE MAY CAUSE DAMAGE TO THE CONTROL WHICH COULD RESULT IN FIRE OR EXPLOSION. If overpressure has occurred such as through improper testing of gas lines or emergency malfunction of the supply system, the control must be checked for safe operation. Make sure that the outside vents on the supply regulators and the safety vent valves are protected against blockage. These are parts of the gas supply system not the heater. Vent blockage may occur during ice storms.

IT IS IMPORTANT TO GUARD AGAINST CONTROL FOULING FROM CONTAMINANTS IN THE GAS WAYS. SUCH FOULING MAY CAUSE IMPROPER OPERATION, FIRE OR EXPLOSION.

All piping must comply with local codes and ordinances or with the National Fuel Gas Code (ANSI Z223.1, NFPA 54) whichever applies. Copper and brass tubing and fittings (except tin lined copper tubing) shall not be used.

REFER TO FIGURE 1 FOR CONNECTION DETAILS. BEFORE ATTACHING THE GAS LINE BE SURE THAT ALL GAS PIPE IS CLEAN ON THE INSIDE.

TO TRAPANY DIRT OR FOREIGN MATERIAL INTHEGASSUPPLY LINE, A DIRT LEG (SOMETIMES CALLED DRIP LEG) MUST BE INCORPORATED IN THE PIPING, SEE FIGURE 1. The dirt leg must be readily accessible. Install in accordance with recommendations of serving gas supplier. Refer to the current edition of ANSI Z223.1.

To prevent damage, care must be taken not to apply too much torque when attaching gas supply pipe to gas valve inlet. The valve inlet has a hexagon shape for use with a backup wrench.

Apply joint compounds (pipe dope) sparingly and only to the male threads of pipe joints. Do not apply compound to the first two threads. Use compounds resistant to the action of liquefied petroleum gases. Do not use teflon tape on gas valve.

DISCONNECT THE APPLIANCE AND ITS INDIVIDUAL SHUT OFF VALVE FROM THE GAS SUPPLY PIPING SYSTEM DURING ANY SUPPLY PRESSURE TESTING EXCEEDING 1/2 PSI (3.5 kPa). GAS SUPPLY LINE MUST BE CAPPED WHEN DISCONNECTED FROM THE HEATER. FORTEST PRESSURESAT 1/2 PSI (3.5 kPa) OR LESS, THE APPLIANCE NEED NOT BE DISCONNECTED, BUT MUST BE ISOLATED FROM THE SUPPLY PRESSURETEST BYCLOSING THE MAIN MANUAL GAS VALVE.

BEFORE PLACING THE HEATER IN OPERATION, CHECK FOR GAS LEAKAGE. USE SOAP AND WATER SOLUTION OR OTHER MATERIALACCEPTABLE FOR THIS PURPOSE. DO NOT USE MATCHES, CANDLES, FLAME OR OTHER SOURCES OF IGNITION TO LOCATE GAS LEAKS.

RELIEF VALVE (P)- See FIGURE 1.

A NEW TEMPERATURE AND PRESSURE RELIEF VALVE COMPLYING WITH THE STANDARD FOR RELIEF VALVES AND AUTOMATIC GAS SHUT OFF DEVICES FOR HOT WATER SUPPLY SYSTEMS, ANSI Z21.22 (CURRENT EDITION) MUST BE INSTALLED IN THE HEATER IN THE MARKED OPENING PROVIDED. THE VALVE MUST BE OF A SIZE (INPUT RATING) THAT WILL BE ADEQUATE FOR YOUR SIZE HEATER.

Check the metal tag on the relief valve and compare it to the heater’s rating plate. The pressure rating of the relief valve must not exceed the working pressure shown on the rating plate of the heater. In addition, the hourly Btu rated temperature steam discharge capacity of the relief valve shall not be less than the input rating of the heater. NO VALVE IS TO BE PLACED BETWEEN THERELIEFVALVEANDTANK. DO NOT PLUG THE RELIEF VALVE.

The drain line connected to this valve must not contain a reducing coupling or other restriction and must terminate near a suitable drain to prevent water damage during valve operation. The discharge line shall be installed in a manner to allow complete drainage of both the valve and line. DO NOT THREAD, PLUG OR CAP THE END OF THE DRAIN LINE.

VENTING

WARNING

NEVER OPERATE THE HEATER UNLESS THE INTAKE AND EXHAUSTARE VENTEDTOTHE OUTDOORSAND HASADEQUATE AIR SUPPLY TO AVOID RISKS OF IMPROPER OPERATION, FIRE, EXPLOSION, ORASPHYXIATION. IFTHE WATER HEATER IS BEING INSTALLED AS A REPLACEMENT FOR AN EXISTING POWER VENTED HEATER IN PRE-EXISTING VENTING, A THOROUGH INSPECTION OF THE EXISTING VENTING SYSTEM MUST BE PERFORMED PRIORTOANY INSTALLATION WORK. VERIFYTHAT THE CORRECT MATERIALAS DETAILEDABOVE HAS BEEN USED, AND THAT THE MINIMUM OR MAXIMUM VENT LENGTHS AND TERMINALLOCATIONAS DETAILED IN THIS MANUALHAVE BEEN MET. CAREFULLY INSPECT THE ENTIRE VENTING SYSTEM FOR ANY SIGNS OF CRACKS OR FRACTURES, PARTICULARLYAT THE JOINTS BETWEEN ELBOWS AND OTHER FITTINGS AND THE STRAIGHT RUNS OF VENT PIPE. CHECK THE SYSTEM FOR SIGNS OF SAGGING OR OTHER STRESSES IN THE JOINTSASARESULT OFMISALIGNMENTOFANYCOMPONENTSINTHESYSTEM.IFANY OF THESE CONDITIONS ARE FOUND, THEY MUST BE CORRECTED IN ACCORDANCE WITH THE VENTING INSTRUCTIONS IN THIS MANUAL BEFORE COMPLETING THE INSTALLATIONAND PUTTING THE WATER HEATER INTO SERVICE.

WARNING

THESE MODELS ARE CERTIFIED FOR VERTICAL VENTING AND SIDE WALL VENTING. THE UNIT CONSISTS OF AN INTAKE VENT TERMINAL AND AN EXHAUST VENT TERMINAL WHICH MUST BE USED TO TERMINATE THE VENTING ARRANGEMENT. IF THE VENT TERMINALS SUPPLIED WITH THIS UNIT ARE NOT USED TO TERMINATE THE VENTING ARRANGEMENT, THE RISK OF IMPROPER OPERATION, FIRE, EXPLOSION, OR ASPHYXIATION WILL INCREASE.

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