When checking the wattage of a heat element with an amp probe, you are allowed a 10% fluctuation either way. Example: If the required wattage is 250W, and the amp reads anywhere from 225-275W, the heat element will work adequately for that refrigerator. If the amp reading is lower than or exceeds the 10% fluctuation, replace the heat element with a new heat element. NOTE: Don’t take for granted that a new one will be the correct wattage. Check it with an amp probe.

My students and customers have often inquired about a plugged cooling unit. On the older model refrigerators, when the refrigerator is operating in an unleveled position, it is supplying unsatisfactory cooling to the refrigerator compartment. This allows the liquid portion of the chemicals in the cooling unit to pick up debris that is lying on the bottom of the cooling unit. (Debris finds it’s way into the unit during factory assembly). The old style boiler tubes have a small inside diameter. This was a contributing factor to a plugged cooling unit. Depending on how much debris is in the cooling unit and how long the refrigerator runs out of level plays a part in how long it runs before it plugs. During detailed testing I found some cooling units would plug in just over one hour, while others would run with insufficient cooling for up to five days before plugging.

When a heat source, (gas or electric), is applied to the cooling unit boiler, it perks like a coffeepot. At the strongest point of perking, the debris is picked up and carried up the boiler tube. Eventually, because of its size and weight, it becomes too heavy to be carried up the full length of the boiler tube. It falls, collects in one area, and forms a blockage. If left running in this condition, the cooling unit overheats and the blockage is baked until it is as hard as a rock. From about 1980 to 1990, I repaired boiler tubes in approximately 30% of the cooling units that I reconditioned. This was the only place I ever found a cooling unit to be plugged. In the case of a plugged boiler tube, follow “The Ford Procedures”.

Troubleshooting

The following conditions would indicate that boiler tube is plugged:

After unit has run for approximately one hour:

• No rapid boil

• No temperature at the top of the steam line just before condenser

• No temperature in the freezer

• Little or no temperature in the bottom absorber coil

• Steam line is extremely hot where it exits the boiler pack.

Reconditioning

The first option is always to try to unplug the boiler tube, then clean and flush the entire cooling unit. If cleaning the boiler tube is unsuccessful, the next option would be to remove the plugged boiler tube and replace it with new tubing. It is critical to pay close attention to the tube length, the inside diameter of the tube, and the size, shape, bends, and turns of the tube. The replacement boiler tube needs to be an exact replacement. Heat element sleeves and flue tubes also have to be removed from the old boiler tube and rewelded on to the new boiler tube. Again, this requires an exact replacement. The good news is that the refrigerator manufacturers have been using a new style of boiler for some time. The plugged cooling unit will only be found on very old models. My compliments to the refrigerator manufacturers.