Lochinvar 500, 90 service manual Additional Temperature Controls

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Installation & Service Manual

5Electrical connections

Shutdown

The Shutdown knob specifies the outdoor air lockout temperature at which the control would prevent the unit from operating.

Outdoor Air Max (O.A. Max)

The O.A. Max knob allows a reset up to the maximum outdoor air temperature specified by this knob setting. When the outdoor air temperature is above the specified setting, the unit will not function in the O.A. Reset Mode, but will continue to run at the selected set point temperature.

Note that the set point knob will now indicate the “minimum” boiler temperature. Target temperature is determined by the ratio and outdoor air temperature below the O.A. Max setting.

Ratio

The Ratio knob allows control over the reset ratio to be used during Outdoor Air Reset. The allowable ratios are as low as 0.5:1 or as high as 1.5:1.

Selecting the 0.5:1 ratio will increase the set point 0.5° for every 1.0° drop in outdoor air temperature up to the maximum set point temperature.

Selecting the 1.5:1 ratio will increase the set point 1.5° for every 1.0° drop in outdoor air temperature up to the maximum set point temperature.

If the outdoor design and boiler design temperatures are known, the Ratio setting can be calculated using the following formula:

Ratio = (boiler design temperature - operator set point)

(O.A. Max. setting - outdoor design temperature)

Note that the reset set point cannot exceed the maximum set point of the boiler thermostat.

These settings are illustrated graphically in FIG. 5-7.

Figure 5-7_Outdoor Air Control Example Chart

Outdoor Air Shutdown Enable/Disable Switch

The Outdoor Air Shutdown Enable/Disable switch turns the outdoor air shutdown feature On and Off. Disabling the Outdoor Air Shutdown feature allows the unit to operate regardless of the outdoor air temperature. This is needed for indirect domestic hot water systems for example.

Additional Temperature Controls

High Water Temperature Limit Control

The appliance is supplied with a fixed setting, auto-reset high water temperature limit control. The setting of this control limits maximum discharge water temperature. If water temperature exceeds the setting, the limit will break the control circuit and shut down the appliance. The limit control will only be reset after the water temperature has cooled well below the setting of the limit. The auto-reset high water temperature limit control is mounted in the outlet side of the front header.

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Contents Models 90,000 500,000 Btu/hr Contents Please read before proceeding Checking equipmentCodes Ratings Copper-fin =B=R RatingCopper-fin Specifications Copper-fin How it works Gas connection pipeModels CWN270 Front View Model CWN399 Front View 422 Determine unit location Location of unitDetermine boiler location 3Combustion Air Direct from Outside6Combustion Air from Outside Single Opening Minimum Recommended Combustion AIR Supply to Equipment Room Vent Pipe Sizes VentingConventional Negative Draft Venting System Venting Vertical Vent Termination Clearances Less from Ridge From Parapet WallSidewall Venting Masonry Chimney InstallationVent Materials NumberAutomatic Vent Damper 7CB with Vent Damper and Vent Damper Terminal BlockGas Connection Gas connectionsGas Supply Gas Pressure Test Manifold PressureInstall Piping to Control Gas PipingGas Manifold Pressure Adjustment Procedure Clockwise to raise regulator gas pressure, counterclockwiseChecking Gas Supply Pressure 4Gas Supply PressureTwo Stage Burner Control System Combination Gas ValvesVenting of Combination Gas Valves Relief Valve Water Flow Switch if equippedHydronic piping Minimum Required Flow For Heating Boiler Typical Heating Boiler InstallationsLow Water Cutoff if equipped General Plumbing RulesSystem Temperature Rise Chart Piping of the Boiler SystemWater Connections Heating Boilers Only Heat Exchanger Pressure Drop ChartCirculator Pump Specifications Circulator Pump RequirementsPrimary/Secondary Boiler Piping Three Way Valves Boiler Flow RatesPrimary / Secondary Piping 4Primary / Secondary Piping of a Single BoilerNot to Exceed 4 Pipe DIA or MAX. of 12 Apart 8Multiple Boilers Zoned with Circulators Power Venter Connection to Terminal Strip Terminal Strip WiringBoiler Operating Temperature Control Electrical connectionsOperating Temperature Control Temperature AdjustmentPump Wiring for a Heating Boiler Maximum SET Point Determination Locating Temperature ControlTemperature Control Settings Maximum Set Point DeterminationMulti-Purpose Temperature Sensor Temperature Control SensorsInlet Water Temperature Sensor Outdoor Air Temperature SensorInstallation of a Tank Sensor Water Heater Application Outdoor Air Reset OptionInstallation of a Remote Sensor Boiler Application Additional Temperature Controls Blocked Vent and Flame Roll-Out / Flame Interlock Switch Manual Reset High Water Temperature Limit ControlInitial Start-up Pre-start ChecklistStart-up Lighting Instructions 1Gas Valve 90,000 270,000 Btu/hr ModelsSafety Shutoff Test For Standing Pilot Ignition System To Turn OFF GAS to ApplianceOperating Instructions Freeze Protection Safety Shutoff Test for Spark Ignition Pilot SystemIntermittent Pilot Spark Ignition System F9/M9 To Turn Off Gas to ApplianceWater Treatment Freeze Protection for a Heating Boiler System if requiredDomestic water heaters Required Temperature RiseRequired Temperature Rise Domestic Water Heaters 90,000 500,000 Btu/hr ModelsPump Operation Water ChemistrySoftened Water Systems 1Single water heatersingle tank 2Single water heatermultiple tank 3Multiple water heatersingle tank Minimum Pump Performance Remote Sensor InstallationThermostat Settings Heat Exchanger5Danger Warning Thermal Expansion Water Flow Switch if equippedPressure Only Relief Valve Cathodic ProtectionOwner maintenance Maintenance and annual startupService technician See the User’s Information Manual for instructionsMaintenance Check Expansion Tank Check Relief ValveCombustion Air Adjustment Check All WiringCheck Control Settings Perform Start-up and ChecksInspection and Cleaning Procedure Inspect and Clean BurnerHeat Exchanger / Burner Access Inspection of Heat Exchanger Waterways Pilot Flame Adjustment ProcedureClear Area Water Circulating PumpReview with owner Gas Train and ControlsTroubleshooting Pilot or replace Wiring Diagram F1 Unit DiagramsSchematic Diagram F1 Unit 90,000 270,000 Btu/hr Models315,000 399,999 Btu/hr Models Schematic Diagram F9 UnitWiring Diagram F9 Unit Diagrams Diagrams Page Revision a ECO #C06290 initial release CFA-I-S Rev a 09/10
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