Caleffi Valves
Caleffi manufactures Italian-engineered pressure reducing valves, thermostatic mixing valves, zone valves, backflow preventers, air separators, and expansion vessels for hydronic heating/cooling and domestic plumbing systems. Their 535H Series PRV and 521 Series mixing valves are widely specified in commercial and residential applications.
Caleffi Valves Product Lines
Certifications & Standards
Valves How-To Guides
View All →How to Replace a Shut-Off Valve
Swap a stuck, leaking, or unreliable shut-off valve for a modern quarter-turn ball valve -- compression, threaded, and push-fit connections all covered.
How to Adjust a Pressure Reducing Valve
Test your water pressure, find the PRV on your main line, and adjust it to a safe 50-60 PSI -- before high pressure wears out your fixtures, appliances, and water heater.
How to Fix a Leaking Gate Valve
Stop a dripping gate valve stem -- tighten the packing nut, replace the packing, or swap the whole valve for a ball valve, depending on what the situation calls for.
Common Valves Problems
View All →Stuck Shut-Off Valve
Usually discovered during an emergency -- something is leaking and the valve will not budge. Older gate valves seize after years of disuse. Fix ranges from penetrating oil and patience to full replacement.
Leaking Valve Stem
Water dripping from around the valve handle or packing nut -- packing failure, not a pipe leak. Fix is usually tightening the nut or replacing the packing, often with the water still on.
PRV Failure -- High Water Pressure
Failing PRV lets dangerously high pressure into the house. Bursts supply lines, damages appliances, causes hammer, shortens fixture life, leaks everywhere. Normal is 40-60 PSI. Above 80 is dangerous and needs immediate attention.