A.O. Smith HYB-90N warranty Heat Cycle Definitions, State, Description

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HEAT CYCLE DEFINITIONS

HEAT CYCLE DEFINITIONS

STATE

DESCRIPTION

Pre-purge

If the heat engine initial call-for-heat is successful (all checks are passed), the combustion fan

 

is energized. The fan is started at a high speed for several seconds and the system verifies the

 

fan speed. Input signals (from other parts of the water heater) are verified before completion of

 

pre-purge including fan current verification. If one of the checks fails then the unit moves into

 

the post-purge mode followed by the hard lockout mode and the appropriate error is displayed

 

(see Error Code List and Clear-out Procedure).

Inter-Purge

If the flame presence is detected the control delays a pre-determined amount of time keeping

 

the spark igniter energized. If flame presence is not detected within 5 seconds from the

 

moment the gas was allowed in the combustion chamber (three ignition trials) then the control

 

will initiate an ignition re-try for two more times. If flame presence cannot be verified within

 

the given timing and after the ignitions’ re-try (if applicable), the system enters the post-purge

 

mode and the gas flow is turned off.

Post-Purge

The heat engine gas valve is now turned off and the fan speed is changed to high speed for

 

a predetermined time followed by a change of fan speed to a low value for the remaining

 

duration of the post purge mode. The control will also verify that the proper conditions are

 

maintained and there is no flame current sensed from the flame rod. If during the first stage

 

of the post-purge mode (high speed fan operation) conditions for a new call for heat are met

 

then the system will allow the state change to “Initial call for heat” only after the first stage of

 

the post-purge mode is complete.

Standby Mode

After successful completion of post-purge, the fan is turned off and the control will wait until

 

the determined conditions for a call for heat are met. In standby mode the unit continually

 

monitors the input and output conditions and if abnormal conditions are detected the unit will

 

enter in a lockout mode. If a call for heat is required and all checks are passed, the control

 

will return to the initial call for heat state.

Lockout mode

This is a non-operational mode following the detection of an error in the system. In this stage

 

the system displays an error message and continuously monitors input and output parameters.

 

The system can move from this state into the stand-by mode only if the error is cleared (typical

 

values for input and output parameters are recorded).

Proven Ignition

Once the power is turned on, the self-inspection is getting a normal status, water is turned

 

on and fan’s current is normal then the ignition process will start for 5 seconds. If ignition is

 

successful, the heater will go to normal combustion state and the ignition sparking will stop

 

after 3 seconds. If ignition fails, the control will attempt to cycle through the heating stage

 

three times and then attempt to re-ignite the gas. If ignition cannot be achieved, the control

 

will end ignition attempts and prevent any more heating cycles, close the gas valve, turn the

 

blower on, and display the E28 error message to the user.

 

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Contents POWER VENT GAS MODELS For Your SafetyInstallation and Operating Manual HYBRID GAS WATER HEATERSIMPORTANT INFORMATION TABLE OF CONTENTSIMPORTANT DEFINITIONS SAFE INSTALLATION, USE AND SERVICEGENERAL SAFETY DANGER INTRODUCTION Page GET TO KNOW YOUR WATER HEATER - GAS MODELS REPLACEMENT PARTS AND DELIMING PRODUCTSROUGH IN DIMENSIONS INSTALLATION CONSIDERATIONSINSTALLATION REQUIREMENTS FOR THE COMMONWEALTH OF MASSACHUSETTS Water Potable Heating All models are considered WATER PIPING - MIXING VALVE USAGEFACTS TO CONSIDER ABOUT LOCATION HANDLE INSTALLATION Access To EARTHQUAKE ZONESTop Casing Front ScrewsAPPLIANCES IN UNCONFINED SPACES COMBUSTION AIR AND VENTILATIONAPPLIANCES IN CONFINED SPACES B. ALL AIR FROM OUTDOORS See Figures 12, 13 and WATER PIPING CHEMICAL VAPOR CORROSIONCLOSED WATER SYSTEMS THERMAL EXPANSIONTEMPERATURE-PRESSURE RELIEF VALVE HARD WATERT&P Valve and Pipe Insulation if supplied SEDIMENT TRAPS GAS PIPINGGAS LINE PURGING HIGH ALTITUDE INSTALLATIONSFLOODING/FREEZING FILLING THE WATER HEATERVENT PIPE TERMINATION If using 2 inch vent pipePLANNING THE VENT SYSTEM RODENT SCREEN INSTALL INTO ELBOW GROUND LEVEL OR MAXIMUM SNOW LINE If using 3 inch vent pipeTERMINATION ELBOW ELBOW STRAPVENT TERMINAL INSTALLATION, SIDEWALL INSTALLATION OF VENT SYSTEMCONDENSATE CONDENSATION WARNINGINSTALLATION SEQUENCE SEQUENCE OF INSTALLATIONSVent terminals supplied with heater must be used INSTALLATION OF VERTICAL VENT SYSTEM INSTALLATION OF VENT SYSTEM, SIDEWALLVENT PIPE PREPARATION STEP A RECOMMENDED BRUSH* SIZE FOR PRIMER AND CEMENT APPLICATIONSSTEP B STEP E U.S. POWER VENTSTEP F STEP G CONNECTION TO VENT PIPEVENT HOODS MAY BE EXTREMELY HOT DURING OPERATION CALIBRATION ELECTRICAL CONNECTIONSFIGURE 33a “OFF”, “up”DISPLAY PANEL OPERATING INSTRUCTIONSNumeric Display DISCONNECTION WHEN SERVICING CAUTION LABEL ALL WIRES PRIOR TOCONTROLS. WIRING ERRORS CAN CAUSE IMPROPER AND DANGEROUSFOR YOUR SAFETY READ BEFORE LIGHTING LIGHTING INSTRUCTIONSOPERATING INSTRUCTIONS TO TURN OFF GAS TO APPLIANCESTATE HEAT CYCLE DEFINITIONSDESCRIPTION TEMPERATURE REGULATION Temperature Probes UNIQUE HYBRID FEATURESWater Circulation Pump Line Voltage Monitor Detection of Failure to Maintain Desired Constant Temperature CONSTANT OUTPUT TEMPERATURE CONTROLSTART UP CONDITIONS OPERATIONAL CONDITIONSHOUSEKEEPING MAINTENANCEVENTING SYSTEM INSPECTION BURNER OPERATION AND INSPECTIONCLEANING THE INLET WATER FILTER ANODE ROD REPLACEMENTTEMPERATURE-PRESSURE RELIEF VALVE OPERATION MOTORSFLUSHING THE HEAT EXCHANGER LIME BUILD- UP CLEANING THE HEAT ENGINEDRAINING THE TANK FAULT INDICATION AND ERROR CODESDiagnostic DIAGNOSTIC DISPLAYCode and DisplayedLockout FaultCause RemedyLockout FaultCode DescriptionLockout TROUBLESHOOTING Check if there is any error code on WHEN THE TAP IS OPENEDb.The unit display is an error code system installed, or there is aLEAKAGE CHECKPOINTS SERVICEITEM # PARTS IDENTIFICATIONA Baffle, Flue B Hot Water Outlet Nipple w/ Anode, Heat Trap AB C DEF G T SH R I Q P KIT # REPLACEMENT PARTS DESCRIPTIONSERVICE AND LABOR RESPONSIBILITY LIMITED RESIDENTIAL GAS WARRANTYCLAIM PROCEDURE CONDITIONS AND EXCEPTIONSPage Page 500 TENNESSEE WALTZ PARKWAY ASHLAND CITY, TN PHONE 1-800-433-2545 FAX