Removing The Resistor; Inspection; Replacing The Resistor - BIRD ECONOLOAD 8730 Series Operation Manual

Removing the Resistor

Numbers in brackets [ ] refer to the labeled parts in
shown for some models.
1. Disconnect the load from the RF line and the interlock control box, remove the water hoses, and drain off any
water still in the load.
2. Turn the load on end with the hose fittings up.
3. Remove the screws from the back of the water chamber assembly. These secure the water chamber assembly
to the load housing [0].
Note: The 8731 has only one screw, on the side of the water chamber assembly. Also, the water
chamber is threaded, and screws into place. Turn the water chamber counterclockwise until the
threads disengage before pulling the assembly out.
4. Pull the water chamber assembly out.
Note: It may be necessary to rock the chamber gently while pulling.
Note: If the resistor is intact then the entire resistor assembly [2] may be pulled straight out of the
load housing.

Inspection

When the resistor has been successfully removed, inspect it carefully to insure that it has not been fractured. In
most cases, even in the event of complete resistor burnout the resistor will remain intact.
Examine the inside of the load housing and water chamber for damage to internal parts, especially the resistor O-
Ring seal and the resistor contact strip. If the O-Ring has cracks or if the contact strip has missing fingers, replace
them. If the resistor did fracture, thoroughly rinse all parts under clear running water and dry before any assembly.

Replacing the Resistor

If the resistor breaks, there may be splinters or sharp pieces inside the load housing.
Do not remove the resistor plug. Any attempt to do so will cause leakage and resistor
1. Insert the plugged end of the new resistor into the resistor fitting of the center conductor assembly [8] to test
its tightness.
2. The resistor should be snug but should not have to be forced into the fitting.
Note: If the resistor is too loose, press the fitting fingers together slightly and try the resistor again.
Continue closing the ends of the resistor fitting until a snug fit is obtained.
3. Bottom the resistor in the fitting.
4. Put the resistor and center conductor in the load housing [0].
5. Screw the flow tube [7] into the water chamber assembly. Make sure it is screwed in completely to avoid
damaging the resistor.
6. Put the water chamber [3] back into the load, gently rocking and twisting the chamber to achieve a flat seat on
the outer housing. Line up the holes with the holes in the load.
7. Tighten the water chamber screws [4].
8. Check the dc resistance between the inner and outer conductors; it should be about 50 ohms. Record this
measurement as the new baseline reading.
9. Connect the load to the coolant supply and cycle the coolant for five minutes. Check for leaks.
Figure 7. Parts may appear slightly different than what is
WARNING
Be careful when repairing to avoid being cut.
CAUTION
damage.
Maintenance
14