Definitions Pump Differential Pressure Required System Capacity Sizing & Capacity Split Equipment Selection System Controls

System Controls


Canariis Corporation uses standardized industrial grade U/L listed and/or recognized components with a "unit circuit" concept when possible. A variety of standardized "unit (or sub) circuits" are combined to provide optimum results with a minimum of components. While each panel is custom, it is comprised of the same circuits over and over - panel to panel. When additional flexibility and circuit complexity is required an industrial grade programmable controller may also be used. These approaches, we believe, give the best of both worlds, a custom approach coupled with recognized circuitry which field service personnel should be easily able to trouble-shoot or field modify if necessary.

The control panel consists of two major circuits. The motor power circuit and the control circuit all housed in a suitable enclosure. All Canariis Corporation panels are U/L LISTED ENCLOSED INDUSTRIAL CONTROL PANELS.

The motor power circuit consists of the main disconnect(s), fuse blocks and fuses, or circuit breakers, magnetic starters with 3 leg overload protection, resets, and all necessary power wiring.

The control circuit consists of a fused 115 volt control transformer with low voltage control wiring and all necessary relays, timers, switches, lights, push buttons, alarms, contacts, alternators and phase and voltage protection devices as necessary. The control circuit can incorporate a programmable controller which will replace all applicable relays, timers and alternators.

Sequencing of Pumps


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.


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.


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.


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:


1st stage
(P1 & P2)
2nd stage

Pumps can be alternated

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

1st stage
2nd stage
(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


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.


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.


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.

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, B or C are most suitable for up to 3 stages and Option D is most suitable for 5 stage sequencing.

Control Panel Features and Options

  1. Control Panel Enclosures - refer to NEMA definitions for all control panel options.


  2. Power Circuit Options - one main disconnect with fused motor circuits, individual disconnects with fused motor circuits, or one main disconnect with motor branch circuit breakers.


  3. Each A/C motor starter is a full voltage, non reversing magnetic starter and is provided with adjustable 3 leg overload protection with manual overload reset push button.


  4. Each pump is provided with a panel mounted light (green) which illuminates when the pump is running, and H-O-A switch for manual and automatic operation. The hand or manual mode will not override system protection devices such as over temperature protection.


  5. Control Circuit will be 115 volt A/C and the transformer will be provided with two fuses on the primary and one fuse on the secondary.


  6. Thru the Door Reset buttons allows resetting the motor overloads when tripped without opening the panel. Reset is manual.


  7. Motor Overload Indicating Light (red) when illuminated indicates a tripped motor overload. This circuit will automatically start the next pump in the sequence. The motor reset is manual.


  8. Control Power (on-off) Switch and Light (amber) provides a means of isolating the control circuit without disconnecting the incoming power at the main disconnect. The light provides visual indication of power to the control circuit.


  9. a) Low Suction Pressure Shutdown with light (red) - suitable only if suction pressure is normally over 15 PSI. This equipment safety feature senses the pressure in the suction manifold; if the pressure drops below a preset point (determined by job conditions), all pumps will immediately shut off. Reset is automatic upon rise in suction pressure. This option guards against loss of suction pressure and potential contamination of the water supply.

    b) Low Suction Level Shutdown with light (red) - this option involves the use of a level sensor on systems taking suction from a tank or reservoir. It protects pumps against running dry. The level sensor is provided for installation by others. It is a displacement type liquid level sensor (which avoids having mercury filled switches in the potable water). Reset is automatic upon rise in tank level. Example: Many cities require an "air gap"; they will not allow pumping directly from their mains; consequently a tank is used. Note: It may be appropriate to use a booster system without PRV's in this situation, since suction pressure is constant.


  10. Low System Pressure Circuit with light (red) - Often called "Lead Pump fail protection". This feature automatically starts one of the main pumps after a time delay if the pressure sensed in the booster's discharge manifold drops below a preset point (determined by job conditions). Panel indicator light remains on until manually reset.


  11. High Suction Pressure Shutdown with light (amber) - This energy saving option senses the suction pressure by means of a pressure switch. If the supply pressure rises above the system switch-off point and remains there for at least 20 seconds all pumps are turned off because the supply pressure is sufficient to satisfy water demands without them. The system automatically restarts when the suction pressure drops.


  12. High System Pressure Shutdown with light (red) - Instantly shuts down all of the pumps and illuminates an alarm light if the discharge pressure exceeds a predetermined value (15 PSI above design) in order to protect piping, valves and other building fixtures from damage by over pressure. Reset is manual


  13. Audible Alarm - This consists of a buzzer which is activated whenever any of the alarms are energized. It also includes a silence button.


  14. Manual Alternation (2) equal pumps - Selector Switch provides manual selection of the pump sequencing.


  15. Manual Alternation (3) equal pumps - Selector Switch provides manual selection of the pump sequencing.


  16. Auto Alternator - Two equal pumps. This feature will automatically alternate the sequence of the pumps on each shutdown cycle and equalize their running time.


  17. Auto Alternator - Three equal pumps. This feature will automatically alternate the sequence of the pumps on each shutdown cycle and equalize their running time.


  18. 24 Hour Time Clock - Two equal pumps. This feature will automatically alternate the sequence of the pumps at a predetermined time once every 24 hours.


  19. Seven Day Time Clock will automatically start and stop the booster system to coincide with the predetermined hours of building occupancy and provide intermittent system operation. This option is provided with an overriding low system pressure circuit and must include option 20 or 21.


  20. System Temperature Probe and Purge Valve. A temperature sensing device senses heat buildup in the system. If the water temperature increases to an excessive value, (approximately 110°F) the temperature probe circuit will open a valve. The opened valve allows the heated water to flow out, and cool water from the suction side to flow in. Reset is automatic.


  21. Individual Pump Temperature Probe and Purge Valve. The operation and purpose of this device is the same as described for option 20 above except each pump is equipped with a temperature sensing probe and valve device mounted on or as close as possible to the pump volute. Reset is automatic.


  22. Flow Switch to limit lead pump on/off cycling. This feature is used in conjunction with intermittent lead pump operation and the hydro-pneumatic tank option. A flow switch is mounted on one of the system manifolds and is wired in parallel with the lead pump start pressure switch and minimum run timer. This prevents high flow rate shutdowns, lead pump short cycling and maximizes the amount of stored water available from the hydro-pneumatic tank.


  23. Elapsed Time Meters are not reset able and provide a record of the hours of operation for each pump.


  24. Remote Alarm Panel with silence push button and light notifies personnel in a remote location of a system problem. The silence button does not extinguish the light. The problem must be corrected before the light goes out.


  25. Auxiliary Relay Contacts provides a means of tying the booster system operation into another control system.


  26. Test Button for purge valve allows manual operation of the temperature protection system, option 20 or 21.


  27. Phase Loss, Low/High Voltage Shutdown provides protection for the electric circuits from single phasing or excessively low or high voltage input.


  28. Key Lockable Enclosure provides protection from unauthorized access or tampering with the system control panel.


  29. Programmable Controller (P.C.) with EEPROM memory and status LEDs for both inputs and outputs. The P.C. replaces applicable standard relays, timers and alternator(s) and is most suitable for complex circuits.


  30. Lightning Arrester (secondary surge arrester) provides protection for the control panel and its components from lightning surges.


Definitions Pump Differential Pressure Required System Capacity Sizing & Capacity Split Equipment Selection System Controls