Lochinvar 402 Anti-cycling, Outdoor air shutdown differential, Shift reset curve, Boost time

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

1 Service (continued)

Outdoor air shutdown differential

The outdoor air shutdown differential parameter is the number of degrees below parameter F5 the outdoor air temperature must go before the unit will respond to a SH demand. The temperature range of this parameter is 0°F (0°C) to 90°F (50°C). The default value is 10°F (5°C).

Shift reset curve

The shift reset curve parameter shifts the actual setpoint above or below the calculated setpoint the number of degrees in this parameter. The temperature range of this parameter is -27°F (-15°C) to 27°F (15°). The default value is 0°F (0°C). This feature will be active if this parameter is set to anything other than 0°F (0°C).

Boost temperature

If a SH demand lasts longer than the programmed time delay setting (F9) and there have been no DHW demands, the control will increase the SH setpoint by the amount in this parameter. If the SH demand continues through another time period, the setpoint will be increased again. This will continue until either the SH demand ends, a maximum of 20 increases has occurred, or the SH user setpoint has been reached. Once the SH demand has been satisfied the setpoint will revert back to its calculated setting. The temperature range of this parameter is 0°F (0°C) to 45°F (25°C). The default value is 0°F (0°C). This feature will be active if this parameter is set to anything other than 0°F (0°C).

Boost time

The boost time parameter sets the amount of time that must elapse with a SH demand before the water temperature setpoint will be increased. The time range for this parameter is 1 minute to 250 minutes. The default value is 20 minutes.

Anti-cycling

Anti-cycle time

Once a demand has been satisfied, a set amount of time must elapse before the control will respond to a new demand. The control will block the new heat demand and anti-cycling will be shown in the display until the time has elapsed or the water temperature drops below the Anti-cycle Override Differential parameter. The time range for this parameter is 0 minutes to 40 minutes. The default value is 1 minute.

Anti-cycle override differential

The control will bypass the anti-cycling time if the inlet water temperature drops too quickly. The control will use the water temperature at the time it shut off as the starting point. If the temperature drops below the temperature parameter the control will abort anti-cycling and allow the unit to fire. The temperature range of this parameter is 0°F (0°C) to 54°F (30°C). The default value is 10°F (5°C).

Minimum On/Off delay Stages 1, 3

Whenever Stage 1 or Stage 3 (if used) starts or stops, a timer is started. This timer must expire before that stage can turn off or back on. The range of this parameter is 0 to 255 seconds. The default value is 60 seconds.

Next on delay

Whenever Stage 1 or Stage 3 (if used) turns on, a timer must expire before another Stage 1 or 3 can turn on, whether in the same heater, or in another heater in a Cascade. The range of this parameter is 0 to 255 seconds. The default value is 60 seconds.

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