tekmar 263 Boiler Control User Manual

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Section C1: Pump Operation

Section C: Pump Operation

Section C1

Pump

Operation

PRIMARY PUMP OPERATION

The primary pump operates under the following conditions:

• A boiler demand is present and the control is not in Warm Weather Shut Down (WWSD).
• A DHW demand is present and DHW MODE is set to 3 or 4.
• A setpoint demand is present and Setpoint MODE is set to 3.

Primary Pump Purge

After a demand is removed, the control continues to operate the primary pump for a period of time. The maximum length of time that
the primary pump continues to run is adjustable using the Primary Pump Purge setting. The primary pump continues to run until either
the purging time has elapsed or the boiler supply temperature drops more than a differential below the Boiler Minimum setting.

BOILER PUMP OPERATION (MODE 2 ONLY)

When the control is operating in Mode 2 - One Modulating Boiler and Pump, the control can operate the boiler pump on the boiler
in addition to the primary pump. The boiler pump turns on prior to the boiler firing (pre-purge) and continues to run after the boiler
is turned off (post-purge). The boiler pump pre-purge time is determined by the Boiler Mass setting. As the Boiler Mass setting is
increased, the boiler pump pre-purge time of the boiler also increases. However, if the control is operating based on a setpoint
demand, the boiler pump turns on prior to the boiler.

Boiler Pump Purge (Mode 2 Only)

The amount of time that the boiler pump continues to run after the boiler turns off is adjustable using the Boiler Pump Purge setting.