Sterlco 140 to 6,285 Gallon Pump Tanks - Manual (Page 37)

Pump Tanks Chapter 4: Operation 37 of 67
4-11 Standby Pump Control
The stand pump’s required IO (one digital output and one digital input per pump) will start
with the first available input and output after the recirc pumps have been assigned their
required IO. The process pump standby will be assigned the first available IO and the recirc
pump standby will take the next.
Standby pumps, if enabled, will activate if the primary pump fails. If pump rotation is
enabled, the standby pump will be used in place of a the primary pump if the primary pump
has more runtime hours than the standby pump when the system is started.
If only one standby pump is installed, the standby pump can function as a process or recirc
pump (SHARED SB). When enabled it will activate whenever the control determines a
process/recirc pump is required. Please see the Process Pump Control and Recirc Pump
Control sections of this document.
4-12 Tower Fan Control
The tower fan’s required IO (one digital output and one digital input per pump) will start with
the first available input and output after the standby pumps have been assigned their required
IO. If there is a VFD on the first fan, the first available analog output after the process VFD
(if present) is assigned its required IO, will be allocated to the tower fan VFD speed signal.
Tower fans are staged on and off to control the tank temperature. When the tank temperature
rises above the FAN ON SP, a fan will activate. If more fans are available, the system will
wait for a period of time (FAN ON STG DLY) before allowing another fan to activate.
When the temperature drops below the FAN OFF SP, a fan will de-activate. When more fans
are active, the system will wait for a period of time (FAN OFF STG DLY) before allowing
another fan to de-activate.
If fan rotation is enabled, the fan with the least amount of runtime hours will activate first and
the fan with the most runtime hours will de-activate first. If rotation is not enabled, fan 1 will
always activate first and fan 2 will always de-activate first. If a VFD is installed on the first
pump, pump rotation is not available.
Note: At least one recirc pump must be active before a tower fan will start.