A.O. Smith HYB-90N warranty Constant Output Temperature Control, Start Up Conditions

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CONSTANT OUTPUT TEMPERATURE CONTROL

CONSTANT OUTPUT TEMPERATURE CONTROL

While the temperature regulation in the previous section describes the features of temperature monitoring and regulation, your water heater goes beyond the on/off control implied there and implements a gas, air and water flow modulation scheme to provide a constant water delivery temperature from the heat engine for the duration of the call for heat.

Heat Needed during Normal Operation

The amount of heat needed is based on the amount of water flowing through the heater and the amount of temperature rise that needs to be generated to meet your demands. The system will calculate the amount of heat needed.

The temperature regulation will prevent the inlet temperature from reaching the temperature set-point.

Detection of Failure to Maintain Desired Constant Temperature

This check can be used to detect a failure of the stage 2 gas valve. In this case, an insufficient amount of heat would be applied. This check can also serve to diagnose failures or mis-wiring of the water flow restriction valve. If the valve fails to restrict the flow of water, the system may not be able to sufficiently heat the water passing through the heat engine.

A failure to maintain the desired constant temperature is determined by the outlet water temperature remaining 15 degrees lower than the set-point for one minute while the flame is established. If this condition is detected while in the heating state for normal modes, an Alert message is provided to the display panel.

START UP CONDITIONS

Smoke/Odor

It is not uncommon to experience a small amount of smoke and odor during the initial start-up. This is due to burning off of oil from metal parts, and will disappear in a short while.

NOTE: If there is a discharge from the temperature- pressure relief valve, refer to the “THERMAL EXPANSION” section of this manual.

NOTE: Do not plug the temperature-pressure relief valve.

Strange Sounds

Possible noises due to expansion and contraction of some metal parts during periods of heat-up and cool-down do not necessarily represent harmful or dangerous conditions.

Condensation causes sizzling and popping within the burner area during heating and cooling periods and should be considered normal. See “CONDENSATE” section.

OPERATIONAL CONDITIONS

Smelly Water

In each water heater there is installed at least one anode rod (see parts section) for corrosion protection of the tank. Certain water conditions will cause a reaction between this rod and the water. The most common complaint associated with the anode rod is one of a “rotten egg smell” in the hot water. The smell is a result of four factors which must all be present for the odor to develop:

a.A concentration of sulfate in the supply water.

b.Little or no dissolved oxygen in the water.

c.A sulfate reducing bacteria which has accumulated within the water heater (this harmless bacteria is nontoxic to humans).

d.An excess of active hydrogen in the tank. This is caused by the corrosion protective action of the anode.

Smelly water may be eliminated or reduced in some water heater models by replacing the anode(s) with one of less active material, and then chlorinating the water heater tank and all water lines. Contact the local water heater supplier or a qualified service agency for further information concerning an Anode Replacement Kit and this chlorination treatment.

If the smelly water persists after the anode replacement and chlorination treatment, we can only suggest that chlorination or aeration of the water supply be considered to eliminate the water problem.

Do not remove the anode leaving the tank unprotected. By doing so, all warranty on the water heater tank is voided.

“Air” In Hot Water Faucets

HYDROGEN GAS: Hydrogen gas can be produced in a hot water system that has not been used for a long period of time (generally two weeks or more). Hydrogen gas is extremely flammable and explosive. To prevent the possibility of injury under these conditions, we recommend the hot water faucet, located farthest away, be opened for several minutes before any electrical appliances which are connected to the hot water system are used (such as a dishwasher or washing machine). If hydrogen gas is present, there will probably be an unusual sound similar to air escaping through the pipe as the hot water faucet is opened. There must be no smoking or open flame near the faucet at the time it is open.

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Contents Installation and Operating Manual For Your SafetyPOWER VENT GAS MODELS HYBRID GAS WATER HEATERSTABLE OF CONTENTS IMPORTANT INFORMATIONSAFE INSTALLATION, USE AND SERVICE IMPORTANT DEFINITIONSGENERAL SAFETY DANGER INTRODUCTION Page REPLACEMENT PARTS AND DELIMING PRODUCTS GET TO KNOW YOUR WATER HEATER - GAS MODELSINSTALLATION CONSIDERATIONS ROUGH IN DIMENSIONSINSTALLATION REQUIREMENTS FOR THE COMMONWEALTH OF MASSACHUSETTS WATER PIPING - MIXING VALVE USAGE Water Potable Heating All models are consideredFACTS TO CONSIDER ABOUT LOCATION HANDLE INSTALLATION EARTHQUAKE ZONES Access ToScrews Top Casing FrontCOMBUSTION AIR AND VENTILATION APPLIANCES IN UNCONFINED SPACESAPPLIANCES IN CONFINED SPACES B. ALL AIR FROM OUTDOORS See Figures 12, 13 and CLOSED WATER SYSTEMS CHEMICAL VAPOR CORROSIONWATER PIPING THERMAL EXPANSIONHARD WATER TEMPERATURE-PRESSURE RELIEF VALVET&P Valve and Pipe Insulation if supplied GAS PIPING SEDIMENT TRAPSFLOODING/FREEZING HIGH ALTITUDE INSTALLATIONSGAS LINE PURGING FILLING THE WATER HEATERIf using 2 inch vent pipe VENT PIPE TERMINATIONPLANNING THE VENT SYSTEM TERMINATION ELBOW If using 3 inch vent pipeRODENT SCREEN INSTALL INTO ELBOW GROUND LEVEL OR MAXIMUM SNOW LINE ELBOW STRAPCONDENSATE INSTALLATION OF VENT SYSTEMVENT TERMINAL INSTALLATION, SIDEWALL CONDENSATION WARNINGSEQUENCE OF INSTALLATIONS INSTALLATION SEQUENCEVent terminals supplied with heater must be used INSTALLATION OF VENT SYSTEM, SIDEWALL INSTALLATION OF VERTICAL VENT SYSTEMVENT PIPE PREPARATION RECOMMENDED BRUSH* SIZE FOR PRIMER AND CEMENT APPLICATIONS STEP ASTEP B STEP F U.S. POWER VENTSTEP E STEP G CONNECTION TO VENT PIPEVENT HOODS MAY BE EXTREMELY HOT DURING OPERATION FIGURE 33a ELECTRICAL CONNECTIONSCALIBRATION “OFF”, “up”OPERATING INSTRUCTIONS DISPLAY PANELNumeric Display CONTROLS. WIRING ERRORS CAN CAUTION LABEL ALL WIRES PRIOR TODISCONNECTION WHEN SERVICING CAUSE IMPROPER AND DANGEROUSOPERATING INSTRUCTIONS LIGHTING INSTRUCTIONSFOR YOUR SAFETY READ BEFORE LIGHTING TO TURN OFF GAS TO APPLIANCEHEAT CYCLE DEFINITIONS STATEDESCRIPTION TEMPERATURE REGULATION UNIQUE HYBRID FEATURES Temperature ProbesWater Circulation Pump Line Voltage Monitor START UP CONDITIONS CONSTANT OUTPUT TEMPERATURE CONTROLDetection of Failure to Maintain Desired Constant Temperature OPERATIONAL CONDITIONSVENTING SYSTEM INSPECTION MAINTENANCEHOUSEKEEPING BURNER OPERATION AND INSPECTIONTEMPERATURE-PRESSURE RELIEF VALVE OPERATION ANODE ROD REPLACEMENTCLEANING THE INLET WATER FILTER MOTORSCLEANING THE HEAT ENGINE FLUSHING THE HEAT EXCHANGER LIME BUILD- UPFAULT INDICATION AND ERROR CODES DRAINING THE TANKCode and DIAGNOSTIC DISPLAYDiagnostic DisplayedCause FaultLockout RemedyCode FaultLockout DescriptionCode TROUBLESHOOTING b.The unit display is an error code WHEN THE TAP IS OPENEDCheck if there is any error code on system installed, or there is aSERVICE LEAKAGE CHECKPOINTSPARTS IDENTIFICATION ITEM #A Baffle, Flue B Hot Water Outlet Nipple w/ Anode, Heat Trap AB C DEF G T SH R I Q P REPLACEMENT PARTS DESCRIPTION KIT #CLAIM PROCEDURE LIMITED RESIDENTIAL GAS WARRANTYSERVICE AND LABOR RESPONSIBILITY CONDITIONS AND EXCEPTIONSPage Page 500 TENNESSEE WALTZ PARKWAY ASHLAND CITY, TN PHONE 1-800-433-2545 FAX