What Is a Jockey Pump and Why Is It So Important?

When discussing sprinkler fire pump systems, most people focus on the main electric or diesel fire pump. However, one of the most important components within the entire installation is often the smallest pump in the pump house – the jockey pump.

Although it is considerably smaller than the main fire pump, the jockey pump plays a vital role in maintaining system pressure and ensuring the fire pumps only operate when genuinely required.

In this article, we'll explain what a jockey pump is, how it works, why it is installed, and the common faults engineers encounter during maintenance and testing.

What Is a Jockey Pump?

A jockey pump is a small pressure-maintenance pump installed within a fire sprinkler system.

Its purpose is simple:

To maintain system pressure during normal conditions and prevent unnecessary operation of the main fire pump.

Unlike the main fire pump, which may deliver hundreds or thousands of litres of water per minute, a jockey pump only provides a relatively small flow rate.

The jockey pump continuously monitors the sprinkler system pressure and automatically starts whenever minor pressure losses occur.

Why Is a Jockey Pump Needed?

No sprinkler system is completely pressure-tight.

Over time, small pressure losses can occur due to:

• Minor valve seepage
• Pipework expansion and contraction
• Temperature changes
• Small leaks within the system
• Pressure gauge connections
• Drain valves not fully closed
• Air release valves
• General system ageing

Without a jockey pump, every small pressure drop could potentially cause the main fire pump to start.

This would result in:

• Excessive wear on the fire pump
• Increased maintenance costs
• Unnecessary electrical consumption
• Battery drain on diesel systems
• Reduced system reliability

The jockey pump prevents this by automatically restoring pressure before the main fire pump start point is reached.

How Does a Jockey Pump Work?

The jockey pump controller monitors the sprinkler system pressure using a pressure switch or pressure transducer.

When the system pressure falls below a predetermined level:

1. The jockey pump receives a start signal.
2. The pump starts automatically.
3. Water is pumped into the sprinkler system.
4. System pressure is restored.
5. The jockey pump stops once the desired pressure is reached.

This process may occur several times throughout the day without anyone noticing.

Under normal conditions, the jockey pump should be the only pump operating regularly.

How Does the Jockey Pump Interact with the Fire Pump?

The jockey pump and main fire pump operate at different pressure settings.

A typical arrangement may look like this:

FunctionExample PressureJockey Pump Stop10.0 BarJockey Pump Start9.5 BarMain Fire Pump Start8.5 Bar

Under normal conditions:

• Pressure drops slightly.
• Jockey pump starts at 9.5 Bar.
• Pressure returns to 10.0 Bar.
• Jockey pump stops.

If a sprinkler head operates during a fire:

• Pressure drops rapidly.
• Jockey pump starts.
• Pressure continues to fall.
• Main fire pump start pressure is reached.
• Main fire pump starts automatically.

At this point, the fire pump takes over and delivers the required water flow for firefighting purposes.

Why Doesn't the Jockey Pump Handle a Fire Demand?

The jockey pump is designed only to maintain pressure.

Its flow rate is extremely small compared to a fire pump.

For example:

Typical Jockey Pump

• 20–100 litres per minute

Typical Fire Pump

• 1,000–10,000+ litres per minute

The jockey pump simply cannot provide the volume of water required to support an active sprinkler system during a fire.

What Happens During a Fire?

When a sprinkler head activates:

1. Water begins flowing through the sprinkler system.
2. System pressure drops rapidly.
3. The jockey pump starts first.
4. The pressure drop continues.
5. The main electric or diesel fire pump starts automatically.
6. The fire pump supplies the sprinkler system.

The jockey pump effectively becomes irrelevant once the fire pump has started because the fire demand is far greater than the jockey pump's capability.

Common Jockey Pump Components

A typical jockey pump package consists of:

Electric Motor

Provides power to drive the pump.

Pump Assembly

Usually a multi-stage vertical or horizontal centrifugal pump.

Pressure Switch

Monitors system pressure and controls pump operation.

Pressure Gauges

Allow engineers to verify operating pressures.

Non-Return Valve

Prevents water flowing backwards through the pump.

Isolation Valves

Allow maintenance to be carried out safely.

Control Panel

Provides automatic operation and fault indication.

Common Jockey Pump Faults

During servicing and maintenance, engineers frequently encounter several recurring issues.

Faulty Pressure Switches

Pressure switches can drift out of calibration over time.

Symptoms include:

• Pump not starting
• Pump running continuously
• Incorrect start and stop pressures

Failed Non-Return Valves

A leaking non-return valve allows pressure to bleed back through the pump.

Symptoms include:

• Frequent cycling
• Unexplained pressure loss
• Excessive pump starts

Pump Mechanical Seal Failure

Mechanical seals wear naturally over time.

Symptoms include:

• Water leakage
• Pump room flooding
• Reduced reliability

Air Locked Pump

Air entering the system can prevent proper operation.

Symptoms include:

• No water delivery
• Excessive noise
• Poor pressure recovery

Worn Pump Components

Impellers and internal components may wear over time.

Symptoms include:

• Reduced performance
• Longer running times
• Failure to achieve required pressure

How Often Should a Jockey Pump Be Maintained?

Maintenance requirements vary depending on the site and applicable standards.

However, routine inspections typically include:

Weekly

• Visual inspection
• Pressure checks
• Leak inspection

Monthly

• Operational testing
• Pressure switch verification
• Control panel checks

Quarterly or Six Monthly

• Full functional testing
• Valve inspections
• Electrical inspections

Annually

• Comprehensive service
• Performance testing
• Component replacement where necessary

Regular maintenance ensures the jockey pump remains capable of protecting the fire pump from unnecessary operation.

Why Jockey Pumps Are Often Overlooked

Many people assume the fire pump is the most important component within the system.

While the fire pump is undoubtedly critical, a poorly maintained jockey pump can create numerous problems, including:

• Excessive fire pump starts
• False alarms
• Battery failures
• Increased maintenance costs
• Reduced system reliability

A healthy jockey pump contributes significantly to the overall reliability of the fire protection system.

Final Thoughts

The jockey pump may be the smallest pump in the fire pump house, but it performs one of the most important roles within the sprinkler system.

By maintaining system pressure and preventing unnecessary fire pump operation, it helps ensure that the main fire pump remains ready to perform when a genuine fire emergency occurs.

At Fire Pump Spares, we understand the importance of every component within a fire pump installation. Whether you're looking for jockey pump spare parts, pressure switches, gauges, non-return valves, controllers, or technical support, our aim is to provide engineers with the products and knowledge needed to keep critical fire protection systems operating reliably.

After all, reliability isn't just about the main fire pump – it's about every component working together when it matters most.