Expansion Block/Orifice Tube: Service and Repair
Removal Procedure1. Remove the air cleaner cover and duct assembly.
2. Recover the refrigerant.
3. Disconnect the liquid line fitting at the orifice.
Important: Cap or tape the open end of the condenser line immediately to prevent contamination.
4. Using needle nose pliers, CAREFULLY grasp the edge of the expansion (orifice) tube without touching the filter screen and pull to remove the tube; cap or tape the evaporator tube to prevent contamination.
If you encounter difficulty during the removal of a restricted or plugged expansion (orifice) tube, perform the following steps:
4.1. Remove as much of any impacted residues as possible.
4.2. Carefully apply heat approximately 1/4inch from the dimples on the inlet pipe. DO NOT overheat the pipe.
Use of the following heat devices:
^ A heat gun
^ A hair drier
^ An epoxy drier
^ An equivalent to one of these heat devices
4.3. While applying heat, use needle-nosed pliers in order to grip the orifice tube. Use a turning motion along with a push-pull motion.
This will loosen the impacted orifice tube and remove the tube.
4.4. Swab the inside of the evaporator inlet line to clean any contamination from the line.
5. Inspect the expansion (orifice) tube for the following conditions and clean or replace with a new tube as indicated:
^ Broken plastic frame; replace tube
^ Filter screen (1,2) torn, damaged or plugged with fine gritty material; replace tube
^ Brass orifice tube (3) damaged or plugged; replace tube
^ Filter screen (1) coated with metal chips, flakes, or slivers; coating may be removed with low pressure shop air and reused if cleaned satisfactorily
If reusing the tube, install a new O-ring (4)
Installation Procedure
1. Lightly coat the new orifice tube O-ring seal (4) with mineral base 525 viscosity refrigerant oil.
2. Remove the cap or tape from the evaporator line.
3. Using needle-nose pliers, CAREFULLY grasp the edge of the expansion (orifice) tube (long filter screen (1) inlet side of tube) without touching the filter screen and insert the tube (short filter screen (2) outlet side first) fully into the evaporator line.
4. Remove the cap or tape from the condenser line.
5. Using a lint-free clean, dry cloth, carefully clean the sealing surfaces of the line fittings.
6. Lightly coat the new O-ring seal (1) with mineral base 525 viscosity refrigerant oil.
Important: DO NOT allow any of the mineral base 525 viscosity refrigerant oil on the new O-ring seal to enter the refrigerant system.
7. Carefully slide the new O-ring seal (1) onto the line fitting until seated.
8. Install the liquid line fitting at the orifice.
Tighten
Tighten the fitting to 27 N.m (20 lb ft).
9. Evacuate, charge and leak test the system.
10. Install the air cleaner cover and duct assembly.