W-Series W-455A

This is an industrial/commercial sealer. Costing between $400 and $700, this device is primarily used to seal and/or make bags from plastic materials using heat and pressure in varying timed measurements, controlled by a set of 3 potentiometers on the front panel.

The first thing to check are the two fuses in the back. This device will not work if either are blown. Regardless of what the outside of the machine says, these are 125/250V 1A and 125V/250V 10A Fast blow. This is due to the ratings on the board, not on the outer casing, and the least rating takes priority for safety.

There are other models of this device, with differing features, including a series intended for 220V applications. Since this device uses a heater element, and timing circuitry, it is best to keep to the voltage that is indicated unless you are familiar with such modification.

How it works
This device is made up of a few basic parts.

3 timers.
The knobs and status lights indicate which of these timers is in effect, and they run in order on each application.
 * Green: Length of heat application.
 * Yellow: Length of solenoid pull (the device that pulls down and holds down the arm over the heater.)
 * Red: Length of time before another application can run, or automatically does run

Heater element
Potentially the most important part, and the one most likely to burn out, as it is being heated when power is applied. This is mounted using two screws, and a number of nuts, mounted on rubber offset mount to prevent contact with the casing.

Solenoid
This device is used to pull the arm down on top of the heater plate, and hold it down after the heater is off to assure a good hold.

PTFE Cover
This cover, mounted to the front, then wrapped around the heater plate and rolled around the tention bar, is important for keeping the bag from melting to the heater element. If any holes develop, this should be cut and advances slighty, until the element is no longer exposed. This is a normal part of maintenance on the machine, and one role can be used for a significant amount of time.

These covers are the same material used on PTFE, or "teflon" oven mats, used for baking. They are interchangeable, and this provides an inexpensive replacement route, even if some cutting to fit may be required.

Small Screws
Since this machine uses a large solenoid against spring steel to crash a spring loaded bar onto the heater plate, the screws are going to come loose. They need to have a decent amount of tightening, as part of the general maintenance. Thread locker can be used, but is not required. The typical small machine screws used in this machine are M4, and sometimes longer screws can be used to accommodate this umping around, but be sure the length does not cause the casing screw to touch anything electrical, including the element. If the casing wears and will no longer take a screw, a longer screw can be used, but may need to be cut to make it short enough to avoid interference.