5
Table A
Input 1
Low Level
Input 2
Pump Stop
Input 3
Pump Start
Input 4
High Level
Pump
State
Alarm
Closed
Open/Closed
Open
Open
Off
-
Closed
Open/Closed
Closed
Open
On
-
Closed
Open/Closed
Closed
Closed
Both on High level (after timeout)
Closed
Open/Closed
Open
Closed
Both on High level (after timeout)
Open
Open/Closed
Open
Open
Off
-
Open
Open/Closed
Closed
Open
Off
Low level
Open
Open/Closed
Open
Closed
Off
Low level
Open
Open/Closed
Closed
Closed
Both on High level (after timeout)
Mode C: Standard Configuration plus Prime Loss
As per Mode A, except Input 1 is connected to a prime loss/flow switch. If at any stage, after pump start
or whilst a pump is running, the prime loss input closes, for a continuous 2 minute period, a fault is immediately
triggered for that pump and duty alternates. Input functions are as follows:
Input
Function
Input 1
Prime Loss
Input 2
Pump Stop
Input 3
Pump Start
Input 4
High Level
Mode D: Pressure Pumping Configuration
Duty Pump: Lead Pump
Standby Pump: Lag Pump
Input functions are as follows:
Input
Function
Input 1
Not used
Input 2
Input 3
Input 4
If there is a low level alarm , then both pumps will be locked out until the alarm is manually reset.
This lockout will only be overidden upon a high level condition where both the Pump Start and High
Level inputs are closed.
Note that after a high level is triggered, the pumps will both run until the pump Start and Stop
inputs are opened.
Typical operation for Mode D
Low pressure switch (set at say 200kPa)
Lag pump pressure switch (set at say 350kPa)
Lead pump pressure switch (set at say 350kPa)
Pressure drops to 400kPA: Lead (for this cycle) Pump cuts in.
Pressure increases and Pump cuts out.
Cycle continues with duty (Lead and Lag) alternating between the two pumps.
If pressure drops to 350kPA, Lag Pump will cut in and remain running until Lead Pressure switch
opens circuit. Then duty alternates.
No faults are logged against the Lead Pump if the Lag Pump starts.
The controller has inbuilt timers for”Delayed” Start and Stop to obviate pump chatter. Upon Input 1
contact closure, the pump will not start (delay start) for 3 seconds and will not stop (minimum run time)
for 30 seconds (or 33 seconds from close of Input contacts). This “run on” occurs even if Lead Pressure
switch opens circuit during this initial period. If however run time exceeds 33 seconds,
the pump will stop immediately upon “open circuit” occuring.
If the Lead Pressure Switch input closes circuit as well as the Low Pressure Switch input, both
pumps will be turned on and the Low Pressure Timer will begin counting.If this condition exists for a
period of 60 seconds, then both pumps are shut down and the system signals a level alarm. This
would be typical of a Loss of Prime or Burst Main situation.
Pressure switches are normally Closed and Open on High pressure
