Lochinvar 90, 500 service manual Maximum SET Point Determination, Locating Temperature Control

Page 35

5Electrical connections (continued)

Locating Temperature Control

NOTICE

Remove the control panel door on the front of the unit in order to locate and access the temperature control.

Installation & Service Manual

Anytime that OJ1 is the only jumper cut, a new overlay is required under the Set Point knob on the temperature controller because the scale has changed to a maximum of 190°F.

Temperature Control Settings

Remove the control panel door on the front of the unit unless your unit is specified as a boiler only with an outdoor air reset option. If your unit is a boiler only with an outdoor air reset option, there are additional controls for this option. They are explained under Outdoor Air Reset Option, page 37.

The three setting knobs on the temperature control are for Set point, Differential, and High-Fire Offset (see FIG. 5-4).

Figure 5-4_Temperature Control

Maximum Set Point Determination

The maximum set point for the control is factory set. Boilers can be set to 240°F max., water heaters are set to 190°F max., and specialty state and local codes to 200°F.

These maximum set points are established by cutting the OJ1 and OJ2 jumpers located on the right side of the temperature controller. The maximum set point is determined as shown below in Table 5C.

TABLE - 5C

MAXIMUM SET POINT DETERMINATION

 

OJ1

OJ2

MAX.

 

 

SET POINT

 

 

 

 

 

 

 

 

 

 

 

Connected

Connected

240°F

 

 

 

 

 

 

 

Cut

Connected

190°F

 

 

 

 

 

 

 

Connected

Cut

200°F

 

 

 

 

 

 

 

Cut

Cut

160°F

 

 

 

 

 

 

Anytime the OJ2 jumper is cut (with or without OJ1), a new overlay is required under the Set Point knob on the temperature controller because the scale has changed to a maximum of 200°F.

Set Point

The Set Point knob specifies the target inlet (or system sensor, if used) water temperature in degrees, Fahrenheit. After the water temperature reaches the set point, the temperature control shuts off the burners.

Differential

The Differential specifies the number of degrees below the set point that the control will allow the water temperature to drop before it brings the unit back on again.

High-Fire Offset

The temperature control operates a two-stage firing system. The two stages are High-Fire and Low-Fire. High-Fire operates all burners at full rate while Low-Fire operates the burners at approximately one-half rate.

The High-Fire Offset knob specifies the number of degrees below set point that the High-Fire stage shuts down. At that point, the unit will continue to operate at the Low-Fire stage until the set point is reached.

The High-Fire Offset knob has settings between 0°F and 20°F. If set at 0°F, the High-Fire Offset is disabled and the unit will operate the High-Fire stage until the set point is reached and the temperature control shuts the unit off.

If the High Fire Offset knob is set to 0 or 1, the delay will be 10 seconds; if set to 2 or above the delay will be 120 seconds.

Boiler Application

Standard boiler units are equipped with one inlet water temperature sensor. An optional sensor is also provided for use as a remote system sensor. Boilers with the outdoor air reset option also have an outside air temperature sensor.

Water Heater Application

Water heater units are shipped with an inlet water temperature sensor and a multi-purpose temperature sensor to be used as a tank sensor. The inlet water temperature sensor is factory installed on all water heaters.

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Contents Models 90,000 500,000 Btu/hr Contents Checking equipment Please read before proceedingCodes Copper-fin =B=R Rating RatingsCopper-fin Specifications Gas connection pipe Copper-fin How it worksModels CWN270 Front View Model CWN399 Front View 422 Location of unit Determine unit location3Combustion Air Direct from Outside Determine boiler location6Combustion Air from Outside Single Opening Minimum Recommended Combustion AIR Supply to Equipment Room Vent Pipe Sizes VentingConventional Negative Draft Venting System Venting Less from Ridge From Parapet Wall Vertical Vent Termination ClearancesNumber Masonry Chimney InstallationVent Materials Sidewall Venting7CB with Vent Damper and Vent Damper Terminal Block Automatic Vent DamperManifold Pressure Gas connectionsGas Supply Gas Pressure Test Gas ConnectionGas Piping Install Piping to ControlClockwise to raise regulator gas pressure, counterclockwise Gas Manifold Pressure Adjustment Procedure4Gas Supply Pressure Checking Gas Supply PressureTwo Stage Burner Control System Combination Gas ValvesVenting of Combination Gas Valves Relief Valve Water Flow Switch if equippedHydronic piping General Plumbing Rules Typical Heating Boiler InstallationsLow Water Cutoff if equipped Minimum Required Flow For Heating BoilerPiping of the Boiler System System Temperature Rise ChartCirculator Pump Requirements Heat Exchanger Pressure Drop ChartCirculator Pump Specifications Water Connections Heating Boilers OnlyPrimary/Secondary Boiler Piping Boiler Flow Rates Three Way Valves4Primary / Secondary Piping of a Single Boiler Primary / Secondary PipingNot to Exceed 4 Pipe DIA or MAX. of 12 Apart 8Multiple Boilers Zoned with Circulators Electrical connections Terminal Strip WiringBoiler Operating Temperature Control Power Venter Connection to Terminal StripOperating Temperature Control Temperature AdjustmentPump Wiring for a Heating Boiler Maximum Set Point Determination Locating Temperature ControlTemperature Control Settings Maximum SET Point DeterminationOutdoor Air Temperature Sensor Temperature Control SensorsInlet Water Temperature Sensor Multi-Purpose Temperature SensorInstallation of a Tank Sensor Water Heater Application Outdoor Air Reset OptionInstallation of a Remote Sensor Boiler Application Additional Temperature Controls Manual Reset High Water Temperature Limit Control Blocked Vent and Flame Roll-Out / Flame Interlock SwitchInitial Start-up Pre-start ChecklistStart-up 1Gas Valve 90,000 270,000 Btu/hr Models Lighting InstructionsTo Turn OFF GAS to Appliance Safety Shutoff Test For Standing Pilot Ignition SystemOperating Instructions To Turn Off Gas to Appliance Safety Shutoff Test for Spark Ignition Pilot SystemIntermittent Pilot Spark Ignition System F9/M9 Freeze ProtectionFreeze Protection for a Heating Boiler System if required Water TreatmentDomestic Water Heaters 90,000 500,000 Btu/hr Models Required Temperature RiseRequired Temperature Rise Domestic water heatersPump Operation Water ChemistrySoftened Water Systems 1Single water heatersingle tank 2Single water heatermultiple tank 3Multiple water heatersingle tank Heat Exchanger Remote Sensor InstallationThermostat Settings Minimum Pump Performance5Danger Warning Cathodic Protection Water Flow Switch if equippedPressure Only Relief Valve Thermal ExpansionSee the User’s Information Manual for instructions Maintenance and annual startupService technician Owner maintenanceMaintenance Check Relief Valve Check Expansion TankPerform Start-up and Checks Check All WiringCheck Control Settings Combustion Air AdjustmentInspection and Cleaning Procedure Inspect and Clean BurnerHeat Exchanger / Burner Access Water Circulating Pump Pilot Flame Adjustment ProcedureClear Area Inspection of Heat Exchanger WaterwaysGas Train and Controls Review with ownerTroubleshooting Pilot or replace 90,000 270,000 Btu/hr Models DiagramsSchematic Diagram F1 Unit Wiring Diagram F1 Unit315,000 399,999 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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