Lochinvar 400 - 801 General Operation, How the boiler operates, How the control module operates

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1Service

General Operation

How the boiler operates

The Knight XL uses an advanced stainless steel heat exchanger and an electronic control module that allows fully condensing operation. The blower pulls in gas and air and pushes flue products out of the boiler through the heat exchanger and flue piping. The control module regulates blower speed to control boiler firing rate. The gas valve senses the amount of air flowing into the boiler and allows only the right amount of gas to flow.

How the control module operates

The Knight XL control module receives input from boiler sensors. The control module activates and controls the blower and gas valve to regulate heat input and switches boiler, DHW and system pumps on and off as needed. The user/installer programs the module to meet system needs by adjusting control parameters. These parameters set operating temperatures and boiler operating modes. Boiler operation can be based on boiler outlet water temperature, boiler return water temperature or system supply temperature, depending on the parameter setting.

Sequence of operation

Table 1-1 shows control module normal sequences of operation for space heating and DHW operation. The combined operation sequence is for a typical application, programmed to provide DHW priority.

Service Manual

Access modes

User

The user can adjust space heating and tank target temperatures by pressing the NAVIGATION dial when “￿SETPOINTS” is flashing at the bottom of the display. The date and time, and the temperature units can also be changed.

Installer

Most parameters are available only to the installer, accessible by entering the installer password (5309).

Saving parameters (reference the Parameter Table - Table 1-4 on pages 15 - 18 of this manual)

NOTICE

Please note that the brackets ([]) denote

screen status.

 

 

To save parameters and exit programming:

Press the RIGHT SELECT [SAVE] key and then press the RIGHT SELECT [HOME] key.

To enter a parameter and continue programming:

Press the RIGHT SELECT [SAVE] key 1 time to return to the parameter listings; press again to return to the menu listings. Remember to press the RIGHT SELECT [HOME] key when finished programming in order to save the changes made.

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Contents Models 400 Contents Handling ceramic fiber materials Please read before proceedingNiosh stated First Aid When servicing boiler Maintenance What is in this manual?Service TroubleshootingService Near boiler pipingKnight XL display Navigation DialControl inputs LOW Voltage Connection BoardSmart Control Module Control outputsHow the boiler operates Access modesGeneral Operation How the control module operatesOperation Display From previous page Sequence of Operation Display panel menu access Button Screen Operation Display StatusDisplay panel parameter access Parameter table GeneralSettings Reset Notification Date and Time Temperature units C / FViewable and changeable control parameters Software VersionData Logging Temperature SettingsFunctions DHW Settings Outdoor Reset Anti-Cycling Controlling Sensor SH Ramp DelayControl modes BMS Thermostat Input Active / InactiveCascade Offset Minimum On/Off TimeCirculation pumps Service Notification Service technician Maintenance Maintenance and annual startupOwner maintenance Maintenance Check expansion tank Flue vent system and air pipingCheck water system Check boiler relief valveCheck control settings Check ignition ground wiringCheck all boiler wiring Inspect ignition and flame sense electrodesReview with owner Check flame signalCleaning boiler heat exchanger Model Kit Part Component Number DescriptionCheck control module fuses TroubleshootingBefore troubleshooting Check the followingOperation No DisplayNo Burner Unit Does NotWire Color R/BK and Y Wire Color G and Y Checking temperature sensorsTemperature Resistance Resistance TemperatureBoiler Pump System Pump NoisyNo Pump DHW PumpSwitch/LWCO FlowAnti-cycling Flame Fail IgnHigh Limit Auto ResetFlame Sequence Fan LowFan High GV/RelayFail Fan Speed HighOutlet Temp Flue Temp HighDelta T High HighRem Ctrl Flt Service BlkParameters Progr Low 24 vac Watch Dog ErrorNo Error Stored Write EEPromOr Obstruction Combustion Analysis ProcedureGas Valve Adjustment Gas Supply PressureModel Gas valve adjustment procedureModels 601 Page