Lochinvar 402 - 2072 Service, Outdoor air reset boiler only, 1 OutdoorAir Reset Curve

Copper-fin II/IIE Boiler and Water Heater Service Manual

1 Service

Figure 1-1_Outdoor Air Reset Curve

Outdoor air reset (boiler only)

Outdoor air reset operation

When the outdoor air sensor is installed, the control will calculate the water temperature setpoint based on the outdoor air temperature. As the outdoor air temperature drops, the water temperature setpoint increases. This feature allows the unit to be more efficient in periods of mild weather, see FIG. 1-1.

Minimum air temperature

When the outdoor air temperature drops to this point, the water temperature will be at its maximum setting (FIG. 1-1). The setpoint will continue to increase as the outdoor temperature drops below this setting. The water temperature will be limited by the user setpoint. The temperature range of this parameter is -22°F (-30°C) to 86°F (30°C). The default value is 25°F (-4°C).

Maximum air temperature

When the outdoor air temperature rises to or above this point, the water temperature will be at its minimum setting (FIG. 1-1). The temperature range of this parameter is -22°F (-30°C) to 86°F (30°C). The default value is 70°F (21°C).

Maximum SH setpoint

When the outdoor temperature drops to its minimum setting (F1) the water temperature setpoint will be at this value, if the SH setpoint is set higher (FIG. 1-1). The temperature range of this parameter is 32°F (0°C) to 248°F (120°C). The default value is 180°F (82°C).

Minimum SH setpoint

When the outdoor temperature rises to or above its maximum setting (F2) the water temperature will be at this value (FIG. 1-1). The temperature range of this parameter is 32°F (0°C) to 248°F (120°C). The default value is 70°F (21°C).

Outdoor air shutdown

When the outdoor temperature rises above this point, the control will block all SH demands (DHW demands will still be active). The temperature range of this parameter is 32°F (0°C) to 122°F (50°C). The default value is 80°F (27°C).

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