Problem 1 – Check valve leaks (does not seal)

Symptoms: Fluid flows backward when pump stops.
Causes: Worn disc seat, debris stuck on seat, or damaged spring.
Fix: Disassemble and clean; replace disc or seat if worn. If debris is frequent, install an upstream strainer. If the valve body is damaged, buy a replacement check valve of the same size.

Problem 2 – Check valve won’t open (no flow)

Symptoms: Very low or zero flow despite pump running.
Causes: Valve installed backward, spring too stiff, or disc stuck by debris.
Fix: Check arrow direction. For springtype, verify that line pressure exceeds the cracking pressure. If the valve is old and stuck, order a new check valve with lower cracking pressure.

Problem 3 – Loud banging noise (water hammer)

Symptoms: Knocking sound when pump stops or valve closes.
Causes: Fastclosing swing check valve in highvelocity system.
Fix: Replace with a silent check valve for water hammer. Many users buy a silent check valve online to solve noise complaints.

Problem 4 – External leakage

Symptoms: Water or fluid dripping from flange or bonnet.
Causes: Loose bolts, damaged gasket, or cracked body.
Fix: Retighten bolts evenly. If gasket is old, replace it. A cracked body means you must purchase a new check valve immediately.

Problem 5 – Disc chattering (rapid opening/closing)

Symptoms: Fluttering sound at certain flow rates.
Causes: Flow velocity too low or too high, or wrong valve sizing.
Fix: Adjust system flow or install a smaller/larger check valve.

When should you buy a new check valve?

If repairs cost more than 50% of a new valve.

If the body is cracked or corroded through.

If the valve has failed multiple times in one year.

Where to find affordable check valves? Search for “check valve for sale near me” or contact check valve suppliers for bulk order pricing. For standard sizes (DN50, DN80, DN100), many suppliers keep check valves in stock.