Replace the valves on the Hypro D252 Diaphragm Pump with the replacements included in the Hypro D252 Valve Repair Kit - 9910-KIT2408.
Typically, if your Hypro D252 is in constant use, it is recommended to make sure the valves get replaced every 6 months or 1000 hours to keep your pump performing up to standards.
The valves may be worn out if you notice you are not getting the same pressure you used to. Examine the valves and check if there is any damage to them and replace when necessary.
Hypro 9910-KIT2408 Valve Repair Kit includes: