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Water Overflowing Above Piston
This means the piston bleed valve is not closing all the way correctly.
During the air bleed, the steel ball in the piston's bleed valve should float up and seal against an o-ring.
Two scenarios can cause this seal to fail, allowing water to enter above the piston:
Scenario 1:
Low boiler pressure during chamber fill can keep the bleed valve open, allowing water to flow through. This commonly occurs when the lever is held halfway during the air bleed.
To verify this, check your boiler pressure on either the Odyssey Argos app or the boiler gauge.
Fix:
- Once you see water in the group head, the chamber is fully filled—proceed with your shot. The downward pressure from the piston should close the bleed valve and stop water flow to that area. Any remaining water above the piston will naturally drip down after the shot.
- To prevent water from entering the group when boiler pressure is low, avoid pausing the lever halfway during air bleeding. Instead, raise it fully (in direct) or lower it completely (in spring).
⚠️ If you start the shot but water still rushes out the top we are likely encountering the second scenario
Scenario 2:
The bleed valve is not functioning correctly, causing it to fail to close.
⚠️ Common causes of bleed valve failure:
- Debris buildup preventing proper sealing
- Damaged or misplaced bleed valve o-ring
- Incorrect assembly of the bleed valve components
Check the bleed valve for any of the above issues.
Remove the piston to access the bleed valve at its base. Use the included 3mm Allen key to remove the valve from the piston—you'll find an o-ring and a ball bearing inside.
Below is how the parts are arranged within the valve.
💡 When reinstalling the bleed valve, be careful not to flip it over—the ball bearing could fall out. Often, simply disassembling the valve, cleaning all parts, and reassembling it will solve the issue. If you notice any damaged parts, send us a photo and we'll help with replacements 🙂