Drain Cleaner: Won't Turn on

The armature is the power-producing unit of an electric motor, located inside of a magnetic field. The armature has a commutator, located on its shaft, that has brushes riding on it that supply power to the armature.

To inspect and test the armature, pull the cable out of the drum and then remove all screws on the outside of the drum. Separate the two halves of the drum. Remove the crown nut, washer and the rear drum as well as the screws on the gear case. For this step, you may have to gently tap the gear case off. Separate the two halves of the handle and locate the brush holder. Remove the brush holders and then the armature from the housing.

With the armature removed from the unit, clean it thoroughly with thinner and dry it completely. Next, stand it up on a bench. With an ohmmeter, attach the two ends to both sides of the commutator to measure the resistance of the winding. As you move it around the commutator, the reading number is not important. You are looking for a consistent reading, indicating all windings are good. If it varies, radically reading zero or open circuit, then the armature is bad. Another test is reading. If the ohm reads zero or open circuit, then that indicates a bad armature. The last one is a bar to ground test, which is done by placing one end of the ohmmeter to the tip of the shaft of the armature and the other end to the commutator. If the armature is bad, install a new one.

Install the armature in the housing, reinstall the brushes and reattach the two halves of the housing. Reinstall the gear case, rear drum, crown nut (with washer), the front part of the drum and tighten. Reconnect the cable by pulling up on the power grip shield, inserting the cable in the drum. Use an up-and-down motion until the cable begins to bend and starts to install in the drum. Install the entire cable with the grip shield in the “up” position.

A field coil is an electromagnet used to generate a magnetic field in an electro-magnetic machine. To inspect and test the field, remove the cable from the drum by simply pulling it out. Remove all screws on the outside of the drum and separate the two halves of the drum. Remove the crown nut, washer, and the rear drum. Remove the screws on the gear case. For this step, you may have to gently tap the gear case off. Separate the two halves of the handle and locate the brush holders. Remove them along with the brushes. Remove the armature from the housing and the screws securing the field to the housing. Take the field out.

To test the field, place one end of the multimeter, set to an ohmmeter, on the inlet wire side and the other on the outlet wire side. Do this procedure for all field coils on the field. The readings should be the same – zero or close to. If they are different, or the multimeter reads infinity, then replace the field.

Install the armature in the housing, reinstall the brushes and reattach the two halves of the housing. Reinstall the gear case, rear drum, crown nut (with washer), the front part of the drum and tighten. Reconnect the cable by pulling up on the power grip shield, inserting the cable in the drum. Use an up-and-down motion until the cable begins to bend and starts to install in the drum. Install the entire cable with the grip shield in the “up” position.

The power cord supplies power to the unit. Begin by inspect the power cord for damage. You’re looking for cuts in the wire, exposed wire, missing insulation or anything else that looks suspicious with the cord. To install a new cord, separate the two halves of the handle. Inspect the connection points for tightness and any burn marks (indicating a short). Disconnect the power cord from its connection points. Slide the cord protector off of the power cord and slide it on the new cord. Attach the new power cord to the connection points and position the cord protector in the housing. Rejoin the two haves of the drain cleaner back together.

The switch allows you to control the power to the electric motor. If the unit is not receiving power when you pull the switch, it may require a replacement. Separate the two halves of the housing on the handle. Locate the switch and disconnect any surrounding wires and remove all fasteners holding it to the housing. With the switch now removed, you can test it by attaching a multimeter set to an ohmmeter to the connection points on the switch. The ohmmeter should read zero, or close to zero, in the “on” position. While in the “off” position, it should read infinity. If your switch is reading infinity in both positions, it will need to be replaced. Install the new switch and fasten it down. Reattach any wires and rejoin the two haves of the handle back together.

The brushes supply the motor with electrical power by riding on the commutator. As the brushes wear down, or build up heavy dirt and debris, it can stop the flow of electricity to the motor. To check the condition of the brushes, separate the two haves of the handle on the drain cleaner. With the motor exposed, locate the brush caps, or holders, at the rear of the motor and remove them. Now, inspect the brushes. If the brushes are less than 1/8 of an inch from the wire, they are worn out and need to be replaced. If they have heavy build up of dirt, you can clean them and reinstall them. Install the brushes back into the caps and reinstall back in the motor housing. Reattach the two halves of the unit back together.