Problems, Adjustments, and Troubleshooting

Uneven Temperature Uniformity

Air circulation is very important to proper oven operation. Improper air circulation could result from:

Overload Oven. Leave space between articles on each shelf to allow air to move between parts. Stagger parts from one shelf to another to prevent dead spots in the air pattern.

Cold Spots at Front of Oven. Open the exhauster and intake damper is enough to prevent fouling of the work. Where significant amounts of solvent or moisture are being driven off in the oven, it is necessary to exhaust enough air to remove this material. When the exhaust is increased, the fresh air intake must also be increased. Failure to do this will result in cold spots within the oven, particularly around the doors, since air will be drawn in past the gaskets. When the fresh air intake damper is properly adjusted it will equal out your hot and cold spots within the oven. Maximum rating is with exhaust dampers full open.

CAUTION: Do not exceed maximum permissible solvent load stated on control panel door label.

Hot or Cold Spots within Oven. Ovens are equipped with louvered ductwork. The louvers are factory adjusted for the best temperature uniformity, but may be adjusted to give the best performance for your particular process. These louvers are not designed for frequent adjustment and should be changed only when load requirements make it necessary. Louvers should be opened where the work space is cold and closed where it is hot.

Failure to Reach Set Temperature or Slow Heat-Up

BURNED OUT FUSE. In addition to any fuses in your fused disconnect switch, check all fuses located inside the control panel as shown on the wiring diagram. Depending upon the particular oven involved, it is possible for a fuse to open without affecting the pilot lights or other visible signs and still affect the heat circuit.

IMPROPER LINE VOLTAGE. Check oven nameplate voltage to assure it matches incoming voltage. Measure voltage at oven to determine if excessive line drop is causing a reduced power input. This could be caused by too many devices connected to the same circuit, or by undersized wiring between the oven and line power source.

REDUCED BLOWER SPEED. Loose or worn drive belts could prevent the recirculating fan from attaining its design speed. This results in reduced air flow and inefficient heat transfer from the heat source to the work area.

INCORRECT BLOWER ROTATION. This results in reduced air flow and inefficient heat transfer from the heat source to the work area. (See your installation instructions)

MOTOR DOES NOT RUN. The magnetic motor starter “Motor On” light will not remain on if the overload has tripped. Disconnect power to the control cabinet before opening. Then push the reset button, located on the motor overload relay. In high ambient temperature conditions, nuisance tripping may occur. Note: If high ambient temperature conditions exist, adjusting the overload to a higher setting may be needed.

DEFECTIVE OR IMPROPERLY CALIBRATED TEMPERATURE CONTROLLER. See your temperature control manufacturer’s instructions for the proper operation and adjustment.

TRIPPED OUT EXCESS TEMPERATURE CONTROLLER. On ovens so equipped, the control may require manual resetting. Depending upon the specific devices used, they may be tripped by either an excessively high oven temperature, and unusually low ambient temperature or a sensing failure. Before placing the equipment back into operation determine what caused the safety device to actuate and correct the condition.

DEFECTIVE OR IMPROPERLY CALIBRATED EXCESS TEMPERATURE CONTROL. See the excess temperature control manufacturer's instruction in your manual for the proper operations and adjustment.

CAUTION: If the oven is equipped for use with flammable solvents or vapors, the excess temperature control is factory set at the maximum temperature and must not be exceeded.