The booster system can be designed to operate intermittently or continuously. The majority of Canariis Corporation booster systems are designed for automatic intermittent operation in combination with a hydro-pneumatic tank.

INTERMITTENT LEAD PUMP OPERATION (Lead Pump Control Option A)

The system will remain off until a demand causes the pressure in the system to drop to a preset point and a switch that senses system pressure will close and activate the lead pump. The lead pump will continue to run until the pressure switch deactivates (opens), the pump minimum run timer elapses, and the lag pump(s) if required to meet the demand have sequenced off.

Alternately the automatic start cycle for the lead pump can be an electric 7 day time clock programmed on a predetermined basis to operate the system continuously when the building is occupied switching over to intermittent operation at nighttime and on weekends with an overriding low system pressure switch.

Pressure switches and timers are readily field adjustable and the settings are determined by field conditions and design requirements.

CONTINUOUS LEAD PUMP OPERATION (Lead Pump Control Option B)

If the system is designed with a continuous run lead pump a hydro-pneumatic tank is not required, however, the pumps must be provided with an over temperature protection device, in case the system runs for extended periods of time at little or no flow.

LAG PUMP SEQUENCING

On our standard systems the lead pump operating alone will handle the low demand requirements. When the system demand increases and exceeds the capacity of the lead pump the lag pump(s) are started automatically to share the load.

The lag pump(s) can be sequenced on and off in a number of combinations depending on the number and split of the pumps in the system, the operating efficiency desired, and control method used.

With decreasing demand the pumps are sequenced off in reverse order. (i.e. last on first off)

Duplex systems with equal size pumps can be 2 stage sequenced as follows:

Pump	(P1)	1st stage
Pumps	(P1 & P2)	2nd Stage

Pumps can be alternated

Duplex systems with unequal size pumps can be 3 stage sequenced as follows:

Pump	(P1)	1st stage
Pump	(P2)	2nd stage
Pumps	(P1 & P2)	3rd stage

Pump alternation is not recommended.

Triplex systems with a lead pump and two equal sized main pumps can be 3, or 5 stage sequenced as follows:

Pump	(P1)	1st stage
Pumps	(P1 & P2)	2nd stage
Pumps	(P1 & P2 & P3)	3rd stage

OR

Pump	(P1)	1st stage
Pump	(P2)	2nd stage
Pumps	(P1 & P2)	3rd stage
Pumps	(P2 & P3)	4th stage
Pumps	(P1 & P2 & P3)	5th stage

The two equal sized main pumps P2 & P3 can be alternated.

For other arrangements consult Canariis Corporation.

THE FOLLOWING LAG PUMP SEQUENCING OPTIONS ARE AVAILABLE

PRESSURE SWITCH (Lag Pump Control Option A)

As the system demand increases and the operating pump(s) cannot maintain the preset pressure for a predetermined period of time, the lag pump(s) will start and continue to operate until the pressure switch deactivates (opens) and the lag pump(s) minimum run timer elapses.

CURRENT SENSING DEVICE (Lag Pump Control Option B)

This method uses a control panel mounted current sensing device for each lag pump. As the capacity of a pump increases due to the increasing system demand so does the motor current. When the amp value is equal to the design capacity (duty point) of the pump the next pump in the sequence is activated.

The lag pump(s) will deactivate when the amp draw on the pump that activated the circuit decreases to a preset value and the lag pump(s) minimum run timer (s) elapses.

FLOW SWITCHES (Lag Pump Control Option C)

As the system demand increases beyond the design capacity of the lead pump the lag pump(s) are sequenced on and off by factory set field adjustable flow switch(es). Each lag pump has a switch which is set to activate and deactivate at a predetermined capacity as well as a minimum run timer to prevent short cycling.

PADDLE WHEEL FLOW SENSOR AND DIGITAL FLOW INDICATOR (Lag Pump Control Option D)

As the system demand increases the flow sensor shall be programmed to select the smallest pump horsepower combination to satisfy all conditions of system design. The flow sensor shall provide direct visual indication of flow rate, include necessary pump sequencing switches and shall be readily field adjustable to accommodate changing demand conditions. The flow sensor shall sequence the pumps off in reverse order as flow demand decreases. Minimum run timers will prevent pump short cycling.

Note:
Duplex systems can be 2 or 3 stages using Lead Option A or B and Lag Options A, B, C, or D. Triplex Systems can be 3 or 5 stages using Lead Option A or B. Lag Option A or B or C are most suitable for up to 3 stages and Option D is most suitable for 5 stage sequencing.