///A check valve or sealing head gets hot
Intensifier: high-pressure side

A check valve or sealing head gets hot

Both sides of a healthy pump run at about the same temperature. A clearly hotter check valve leaks internally.

Safety first: Switch off the pump, release all pressure (open the on/off valve or bleed-down valve) and lock out before you open any high-pressure part. Never put a hand or tool near a running jet.
1Quick questionsYour answers put the most likely cause on top.
Where is the heat?
2Check the causes, most likely first 0 of 4 checked
01Leaking discharge (outlet) poppet or seat Most likely

Water flows back from the outlet into the cylinder and heats up.

How to check: Compare left and right after cutting with pressure released. Hot outlet side = outlet valve.

PhotoArt. no.DescriptionReplaces OEMExcl. VAT
10085 Spring Check valve, 05147863
SpringKMT, H2O
 KMT 05147863 · KMT 49894116 € 1.90
10088 Flat Outlet Poppet, 05116561
PoppetKMT, H2O
 KMT 05116561 · KMT 05112776 € 31.80
10089 Retainer, Poppet, LP-IN SLIV, 10118552
PoppetKMT
 KMT 10118552 · KMT 05144670 € 42.29
10090 Spring Guide, Poppet, 05116751
PoppetKMT, H2O
 KMT 05116751 · H2O 102008-1 € 37.80
10091 Valve, Poppet, LP Inlet SLIV 10107894
PoppetKMT
 KMT 10107894 € 19.90

02Leaking inlet poppet Possible

Water is pushed back to the low-pressure side on the pressure stroke; the inlet manifold gets warm.

How to check: A warm inlet water line or manifold points to the inlet poppet.

03Cracked check valve body Less likely

A body crack gives the same heat without visible leaks.

How to check: Inspect the body when the valve is apart.

04Gland nut or output adapter loose Less likely

A loose part lets water pass the seat.

How to check: Torque per manual with pressure released.

Related problems

General advice based on manufacturer manuals and service practice. Always follow the manual of your machine. Not sure? .