Fusion AP Cross-Over Troubleshooting Guide
A cross-over occurs when ISO and resin are allowed to communicate inside the Fusion AP gun. Mixed or partially reacted material can then harden in the gun, manifold, whip hose or fluid passage. Shut the equipment down and relieve pressure before disassembling the gun.
Common causes
- Damaged, worn or contaminated side seals
- Scratched side-seal surfaces on the mix chamber
- A plugged or partially restricted mix-chamber impingement port
- Side seals that do not move freely in their bores
- Weak, damaged or incorrectly assembled side-seal springs
- Worn side-seal O-rings allowing chemical to bypass the seal
- A loose, damaged or improperly seated mix chamber
- Severe A-to-B pressure imbalance caused by restrictions elsewhere in the system
What to inspect
- Remove and clean the mix chamber and side seals using procedures appropriate for the chemical being sprayed.
- Inspect both flat sealing faces of the chamber. Replace a chamber with scratches, grooves, pitting or hardened material that cannot be removed safely.
- Inspect the side seals for chipped edges, uneven wear and chemical buildup. Confirm that each seal slides freely and is spring-loaded against the chamber.
- Replace damaged O-rings and verify that the correct seals, springs and O-rings are installed.
- Clean the chamber ports with the correct-size drill or cleaning tool. Do not enlarge the ports.
- Before returning the gun to service, verify balanced pressure and check the A- and B-side screens, check valves, hoses and supply system for restrictions.
Heat-related cross-over problems
Hot weather can soften seals, reduce chemical viscosity and increase leakage through worn sealing surfaces. A gun that operates normally when cool but repeatedly crosses over after heating up usually has a marginal side seal, chamber face, O-ring or restricted passage that should be corrected rather than masked by changing pressure.
Need help identifying the failed parts? Contact SPF Depot at 318-742-8000 with the Fusion AP chamber size, which side is contaminated, operating pressures and photographs of the chamber and side seals.
