The Small Valve That Can Cause Big Pump Problems

The pump shuts off.

A few seconds later, the water level rises again.

The pump starts.

Stops.

Then starts again.

It is easy to blame the pump.

But sometimes the problem is sitting just downstream.

The check valve.

What Does a Check Valve Do?

In simple terms, a check valve is intended to allow flow in one direction.

When the pump is operating, water travels through the discharge piping.

When the pump stops, the check valve helps prevent water in the discharge line from flowing backwards through the system.

It is a relatively small component with an important job.

What Happens When It Doesn't Close Properly?

Imagine a sump pump has just removed water from a basin.

The pump shuts off.

If the check valve does not properly prevent reverse flow, some of the water sitting in the discharge piping can travel back toward the basin.

The water level rises.

The pump receives another start signal.

Then it pumps some of that same water again.

That can create unnecessary cycling.

Instead of operating when new water enters the system, the pump is repeatedly handling water it has already moved.

Signs of a Check Valve Problem

Depending on the application, you may notice:

• Water returning after the pump shuts off

• Frequent pump starts

• A sudden sound or movement in the discharge piping

• Longer-than-normal pumping cycles

• Pressure fluctuations

• Reverse rotation in some pumping arrangements

• Unusual noise around the valve

• A pump that seems to work harder than it used to

These symptoms do not automatically prove that the check valve has failed, but they give technicians useful clues about where to look.

Check Valve Size and Selection Matter

Installing any valve that fits between two pieces of pipe is not enough.

The valve needs to be appropriate for the application, expected flow and piping system.

A valve that does not open properly can create additional resistance.

A valve that closes poorly may allow reverse flow.

A valve that closes too aggressively in certain systems can contribute to pressure surges and noise.

The pump and the piping system need to work together.

Look Beyond the Pump

When a pumping system begins behaving differently, it is tempting to focus immediately on the largest piece of equipment.

That can lead to replacing or repairing a pump without correcting the system condition responsible for the problem.

Valves, piping, controls, water levels and system conditions all influence how the pump performs.

Good troubleshooting looks at the complete system.

A Small Component Can Have a Big Effect

A check valve costs far less than a pump, but its operation can directly affect pump cycling, system reliability and performance.

If your pump seems to start more often than it used to, water is returning after shutdown or something simply does not sound right, it is worth finding the cause before unnecessary wear adds up.

Academy Pump & Motor specializes in the sales, service and repair of pumps and electric motors in Calgary and surrounding areas.

Call 403-437-7888 or visit academypump.ca to discuss your pump system.