Trash compactor repair

A compactor is a device to compress rubbish. It consists of a ram or crushing device that has 2,000 or more pounds of pressure and a motor to push it. The motor assembly, at the rear, is a chain drive and sprocket combination. Threaded shafts, turned by the chain drive, force the ram down.

There are various electrical controls and safety devices . Some models have blowers to keep heat and odor levels down. No maintenance is required, but electrical and mechanical problems can arise. Electrical problems are those common to all motored appliances — switches and the motor, the leads and their connectors. These appliances do have a number of switches. Thus a typical KitchenAid model has a filter switch, key interlock switch, start-stop program switch, directional switch, drawer front interlock switch, interlock bypass switch, and ram switch.

All these switches can be tested for continuity. They control the operation and safety features. If the trash compactor refuses to start, you go through the usual steps — first check power sources including the cord, plug, the wall plug itself, the fuse or circuit breaker involved, then check out the front safety switch and rear safety switch. Any switch can fail.

Next, the motor and relay (if it has one — the KitchenAid under discussion uses a starting winding rather than a relay) must be checked out. Always assume that the motor is not the culprit in an appliance with a heavy duty motor, such as this one, but distrust everything up to the motor. 

Among principal switches on a compactor are filter switch, key interlock switch, and start-stop program switch. In the Kitchen Aid model, the small fan motor (a 2-speed motor) is not in the main motor circuit. The electrical circuit goes from the three prong, grounded switch (ground is a green wire) to the interlock front switch via the black wire, to the key interlock switch, to the start-stop switch and the ram switch. The ram switch is wired with brown and orange leads off the start-stop switch. Next is the blue lead from the start- stop switch to the directional switch, then to the motor. The Perils of Pauline have nothing on the flow of electrical current to the motor. The motor's start windings are black and red. The main winding lead is blue; a black lead that becomes brown feeds into the motor protection device, then goes to the opposite pole of the main winding, turning on the motor.

The interlock switches, and the ram switch, are simple, basically 2-lead affairs. The directional switch that controls motor operation has six positions. The start- stop switch has two leads for the ram switch and two for the key interlock and directional switches.

If you test switches for continuity, you have to sort out the leads. Some leads can be tested from nearby connectors that come apart. Others will require clips or prongs that penetrate the insulation. On trash compactors with relay switches instead of starting windings in the motor, the relay should be tested for continuity before anything else.

In making continuity tests, you can test often by the color of the leads. (When only two leads are involved, there is no problem.) But in a switch such as the directional switch of the KitchenAid compactor, with six leads in and out, and not necessarily on opposing sides of the switch, it becomes tricky to test all the leads. You need a color-coded chart of wiring destinations to do a thorough test.

As it happens, the only way to test the motor in this unit is by eliminating that directional switch from suspicion. Of course, you can disconnect the motor and test it, or you can use probes that penetrate the insulation and test its leads. But testing a motor for continuity or resistance, using an ohmmeter or a light tester, can be deceptive with its leads connected. If the leads go to switches that are defective, the motor will give a false reading. To some extent, the reverse of this situation is true; a defective switch reading can be falsified because of its connection to a motor, but that would generally be true only in the closed-switch position.

Mechanically, the trouble spots in a compactor would involve the sprockets, the gears, the drive chain, and the threaded shaft or jack-like posts which drive the ram. The chain can break or wear, and the shafts or posts can get so gummed up that the ram can't move completely through its cycle (down and up).

Trash compactors are both free-standing and under- counter types. If you deal with the latter, you have to disassemble mounting brackets. If yours is freestanding, you have the usual peeling of the outer skin. Anyone who has taken off the outer metal covering (or plastic) on any appliance will have no difficulty with this one. Having said that, it should be noted that a special, slotted tool is required for top removal on some Whirlpool compactor models. Mostly, the old screwdriver, pliers, and sockets are involved. Top removal exposes switches; back panel removal exposes the motor, motor relay, and various other electrical and mechanical components.

The reason for so many switches in compactors is that safety precautions are required in a kitchen appliance that crushes things. Some models have two or more switches designed to stop the operation when the door is opened during the actual movement of the crushing ram. These fail-safe switches can, of course, stop the appliance from functioning altogether if they fail.

When the trash compactor refuses to budge, the order of procedure in troubleshooting is: Check out the cord, the plug if any, and the circuit breaker or fuse box.

Look at the drawer (which slides open to receive the trash). If it is not completely closed, because of some object or defect, the motor will not run. Check the safety key lock position (which works much like your car ignition key).

The drive sprocket may be binding, either because of the drive belt or the chain being too tight. The chain should flex about one-eighth to one-quarter inch, the belt about the same or a little more.

Begin the check of the switches. When you close the drawer and turn on the key, you have already sent electrical current through the key switch, and drawer interlock switch. When you push the start switch, the circuit breaker overload switch also comes into play. All these switches must be tested for continuity if the appliance does not start.

The top limit switch keeps the appliance in operation when you take your finger off the start pushbutton switch. The top limit switch, at the top of the power posts, is normally open, and it closes only when the ram moves away from its resting position at the top.

The unbalance switch will operate when the drawer is forced out of position by the incorrect placing of trash. Large objects are supposed to be centered; if they are not, the appliance can go out of balance and force the drawer open, which opens the unbalance switch and stops the motor. At that point, you can push the start button, thus causing the ram to rise. This will confirm the problem — unbalanced load, rather than any defect in the unit.

The direction switch reverses the motor. It is near the top limit switch and is a double-pole, double-throw switch. This switch is in down position when the ram is near the top; it is in its up position the rest of the time excepting at the very beginning and very ending of the compacting cycle. If the ram doesn't reverse correctly, or stops at the bottom of the cycle, it is probably the top limit switch, or something other than the direction switch — for example, the circuit breaker, or fuse.

Because of the unusual number of switches — probably more than in any other appliance — the odds rise that a switch is at fault, rather than the motor or some other aspect, when the appliance fails to operate. If any mechanical problems arise involving the chain or belt, or the posts, pulleys, gears, and other components, these can be checked visually. Don't rush into disassembly without checking the guarantee. In any case, because of the switching complexity, don't take any switches out without marking the leads and consulting the wiring diagram which is pasted on an inside panel and is color-coded.