Category: 

What Is a Jockey Pump?

A jockey pump works together with a fire pump as park of an indoor sprinkler system to put out fires.
Circuit breakers.
Article Details
  • Originally Written By: Dakota Davis
  • Revised By: Carrieanne Larmore
  • Edited By: C. Wilborn
  • Last Modified Date: 19 October 2014
  • Copyright Protected:
    2003-2014
    Conjecture Corporation
  • Print this Article
Free Widgets for your Site/Blog
In 18th-century England, murderers could ask for a lesser sentence by claiming a full moon made them act erratic.  more...

November 20 ,  1945 :  The Nuremberg Trials began.  more...

A jockey pump, or a pressure-maintenance pump, is a small apparatus that works together with a fire pump as part of a fire-protection sprinkler system. It is designed to keep the pressure in the system elevated to a specific level when the system is not in use, so that the fire pump doesn't have to run all the time and the system doesn't go off randomly. It can also help prevent the system from damage when a fire happens and water rushes into the pipes. These devices consist of a three-part assembly. In many places, there are governmental guidelines and recommendations for installing these devices to make sure they work properly.

How it Works

To understand how a jockey pump works, it's important to understand how a fire sprinkler system works. Sprinkler systems consist of pipes with pressurized water in them and heads that are designed to open when they reach a certain temperature. When the heads open, the water pressure in the pipes drops, since water is flowing out of them. When this happens, a large device called a fire pump starts to send more water through the pipes so that the system can continue to put out the fire.

Ad

The purpose of the jockey pump is to keep the water pressure in the pipes within a specific range when there's not a fire, so that the sprinklers won't go off randomly. Since pipes leak, over time, the water pressure inside them automatically goes down. The jockey pump senses this, and then fills them back up to normal pressure. If a fire happens and the pressure drops dramatically, the jockey pump won't be able to keep up, and the drop in pressure will trigger the large fire pump to start sending water.

Secondarily, this pump prevents sprinkler systems from being damaged when the fire pump begins sending water. If a system does not have a jockey pump keeping it pressurized, it may have a relatively low pressure. When the fire pump starts sending highly pressurized water through the pipes, the sudden change in pressure can damage or destroy the system.

Assembly

All jockey pumps consist of a pump, a motor, and a controller. The two main types of pumps available are centrifugal and regenerative turbine pumps. Both have their pros and cons: the centrifugal type is often less energy-efficient, but it needs less maintenance than a regenerative turbine one. Likewise, a regenerative turbine pump can create a lot of pressure with very little power, but it can make the system too pressurized, and needs a lot of maintenance. Which type is best for a system also depends on the size of the system, with centrifugal pumps often being preferred for smaller systems, since they sometimes create less pressure.

The type of motor used also depends largely on the size of the system. The two main choices for jockey pump motors are single-phase and three-phase. Both work largely the same way, though single phase motors are typically used for smaller, lower pressure systems since they're not as powerful. Controllers can also be either single-phase or three-phase, and differ primarily in the complexity of their assembly.

Requirements

Many places have governmental standards for installing and maintaining jockey pumps. In the US, the National Fire Protection Association's (NFPA) guidelines are the standard. These include things such as the recommended power for a jockey pump in relation to a system's size, how long it can take to repressurize the system, and the pressure that it needs to maintain.

Ad

More from Wisegeek

You might also Like

Discuss this Article

anon931084
Post 9

The Jockey pump is fitted with a pressure switch, which will cut in a cut off time. The jockey pump won't start unless there is a leak and the pressure in the pipe line decrease.

While the pressure decreases, the cut in pressure is reached and the motor starts. When the required pressure reaches the cut off pressure, then the motor stops.

Say the cut off is 150 PSI and cut in is 90 PSI. if the line pressure goes beyond 90 PSI, the jockey starts. If the cut off pressure is lower than 90 PSI and the jockey us not able to manage the pressure difference, the main electrical fire pump starts.

anon339687
Post 8

I have the same question. If we assume the water as an incompressible fluid, steel piping as non deformable piece of equipment and if we assume no hydraulic accumulator fitted in the piping system, then, in standby mode, the jockey pump (centrifugal type) should operate continuously (24h/day) because if the jockey pump stops the system pressure will drop instantly.in this way pump is under pressure in a close system without any circulation. Is this true or I missed something?

anon277231
Post 6

@anon78487: That is solved with the installation of a check valve at the discharge of the jockey pump, so that when the jockey is in standby mode, no water is going to return through the system.

anon272427
Post 5

No system will be 100 percent air free (typically air, but can include gaskets, sealing rings and given enough linear feet, pipe). That/those little air pocket(s) provides the pressure cushion, latched behind the check valves, from which the pressure switches in the pump controllers rely on to determine the sprinkler system pressure status.

mandyeats
Post 4

The turbine pump is able to push liquids to higher heights than the simple centrifugal pump. That is probably it's biggest benefit.

littlerascal
Post 3

If the regenerative pump has so many tolerances, is there any benefit to it over the centrifugal type? Is one type better suited to certain types of buildings than other types? I'm doing a unit on building safety for my engineering class and I'd like to learn more about this.

anon78487
Post 1

Nice article about the jockey pump but something confuses me:

If we assume the water as an incompressible fluid, steel piping as non deformable piece of equipment and if we assume no hydraulic accumulator fitted in the piping system, then:

In a standby mode, the jockey pump (centrifugal type) should operate continuously (24h/day) because if the jockey pump stops the system pressure will drop instantly. Is this true or I missed something?

Moderator's reply: Thank you for visiting wiseGEEK and for contributing to the discussion forums. For security reasons, we are unable to list e-mail addresses in posts. Thanks.

Post your comments

Post Anonymously

Login

username
password
forgot password?

Register

username
password
confirm
email