How to Repair a KMT Style On/Off Valve Using Kit #11241

Introduction

Hypertherm is in no way affiliated with the above mentioned manufacturer.

Step 1 — How to Repair a KMT Style On/Off Valve Using Kit #11241

⚠️ Always make sure all high-pressure water has been removed from the valve by the following machine manufacturers' safety instructions. Failure to do so can cause severe injury or death.

• Turn OFF all water pressure to the on/off valve.
• Turn the on/off valve ON to raise the valve stem from the seat.

Image Description: A control panel display shows pressure readings (PSI/(BAR) 0 0) and various icons. Next to it, a gloved hand is shown turning a valve handle on a panel labeled "WATERJET", positioned between "OFF" and "ON" settings.

Step 2

The valve components can be replaced with the valve body mounted to the table.

• Loosen the high-pressure gland fitting using a 1-1/4" wrench.
• Turn the air to the actuator OFF at the controls.

Image Description: A valve body is mounted to a black fixture. A gloved hand is using a 1-1/4" wrench to loosen a fitting connected to the valve body.

Step 3

• Disconnect the air line from the actuator.
• Unthread the actuator from the valve body.
• Remove all the valve components from the valve body with the included dowel.

Image Description: A sequence of images shows hands disconnecting an air line, unthreading an actuator from a valve body, and using a dowel to remove components from the valve body.

Step 4

• Thoroughly clean the interior of the valve body with isopropyl alcohol or a similar cleaning agent before replacing the components.
• ? Visually inspect the top and bottom of the valve bore for cracks/blemishes. If excessive wear or cracks are visible, replace the valve body.
• Slide the O-ring on to the point of the valve stem.

Image Description: A gloved hand cleans the inside of a valve body with a swab dipped in isopropyl alcohol. Another image shows a gloved hand holding a valve stem with a black O-ring being slid onto its pointed tip.

Step 5

• Slide the stainless steel back-up ring on to the valve stem point with the chamfer side towards the O-ring.
• Slide the brass back-up ring on to the valve stem point with the chamfer side away from the stainless steel back-up ring.
• Put the hoop on the high-pressure seal with the sharp edge of the hoop towards the seal.

Image Description: A sequence of images shows a gloved hand holding a valve stem with a stainless steel back-up ring already installed, then sliding a brass back-up ring onto the stem, and finally placing a hoop onto a seal assembly.

Step 6

• Slide the hoop and the high-pressure valve seal onto the valve stem with the hoop towards the brass back-up ring.
• Apply the high-pressure lubricant to the outside diameter of the high-pressure valve seal.
• Put the point of the valve stem into the valve body.

Image Description: A sequence of images shows a gloved hand sliding the hoop and seal assembly onto the valve stem, applying lubricant to the seal, and then inserting the valve stem into the valve body.

Step 7

• Push the valve stem with the dowel until it bottoms out.
• Apply Blue Goop to the actuator threads.
• Thread (hand tighten) the actuator into the top of the valve body until it bottoms out.

Image Description: A sequence of images shows hands pushing the valve stem with a dowel, applying Blue Goop to actuator threads, and threading the actuator onto the valve body.

Step 8

• Reconnect the air line to the top of the actuator.
• Turn the air to the actuator ON at the controls.
• Apply Blue Goop to all surfaces of the seat.

Image Description: A sequence of images shows reconnecting an air line to the actuator, a control panel with the valve set to "ON", and applying Blue Goop to a valve seat.

Step 9

• Put the seat into the bottom of the valve body.
• Clean the high-pressure gland fitting threads and at the top of the nozzle tube of all Blue Goop.
• Reapply Blue Goop to the threads of the high-pressure gland fitting and at the top of the nozzle tube.

Image Description: A sequence of images shows placing the seat into the valve body, cleaning threads of a fitting and nozzle tube, and reapplying Blue Goop to these parts.

Step 10

• Thread the high-pressure gland fitting into the bottom of the valve body.
• Tighten the high-pressure gland fitting using a 1-1/4" wrench.
• Turn the air to the actuator OFF at the controls.

Image Description: A sequence of images shows threading the high-pressure gland fitting into the valve body, tightening it with a 1-1/4" wrench, and turning the air to the actuator OFF on a control panel.

Step 11

• Apply water pressure to the valve assembly to verify there are no leaks.
• Quickly cycle the valve on and off a few times to purge the system of all contaminants before installing the cutting head.
• Re-install the cutting head and continue the cutting process.

Image Description: A control panel display shows high pressure readings (PSI/(BAR) 60000 (4137)). Another image shows a gloved hand turning a valve handle to the "ON" position. A third image shows a valve assembly connected to a hose.