Sentry Industries Sentry Xpress 4.0 manual Problem Controller display turns on. No heat in kiln

Models: Sentry Xpress 4.0

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(in AC mode) to both INPUT connections (the white and orange wires). (See photo on previous page.)

CAUTION: Do not let the back of the board touch a grounded object. Make sure the voltmeter is in the AC mode when placing the probes on INPUT connections.

Controller Power Input Test Result: No voltage UNPLUG kiln. Check the switch box for disconnected

wires between the cord, transformer, and controller. If wir- ing is okay, replace the transformer.

Controller Power Input Test Result: 20 - 24 volts AC Correct current is reaching the board from the trans-

former. But since the board is not lighting up, it is probably defective. Return the controller for repair or replacement.

Controller Power Input Test Result: less than 20 volts Did you recently replace the transformer? It may be the wrong voltage. The voltage is below 20, which is not enough power for the controller. To find out the cause of low volt-

age, continue below:

Controller Input Test #2

The back of the board is still facing you and the kiln is pluggedin. Remove the INPUT plug, which is the white, or- ange, and blue wires, from the back of the controller. Touch a voltmeter probe to the white wire and the other probe to the orange wire.

Input Test #2 with disconnected plug: Touch the voltmeter probes to the white and orange wires to test voltage going to the controller. The voltmeter must be in AC mode.

Input Test #2 Result: Less than 20 Volts AC

There are two possible reasons: 1) Low voltage at the wall receptacle; 2) defective transformer. If wall receptacle voltage is correct, replace the transformer.

Input Test #2 Result: 20 - 24 Volts AC

The transformer is sending correct voltage to the con- troller. Yet when the INPUT plug was connected to the controller, voltage was less than 20. This means the control- ler is draining the voltage and may be defective. Return the controller for repair or replacement.

Problem: Controller display turns on. No heat in kiln.

Is the relay making its normal clicking sound?

Test the elements with an ohmmeter:

Element Resistance Test

UNPLUG kiln/disconnect the power. Open the kiln’s switch box. Make sure the wires connecting the relay to the elements are secure. If connec- tions are okay, continue to step 2:

Touch the ohmmeter leads to the two element con- nectors of each element. A no-needle-movement reading on an analog meter, or OPEN on a digital meter, indicates a broken element.

If the elements check out okay, replace the relay.

Note: To replace relay, see your kiln’s instruction and service manual.

We know the controller is receiving voltage, because the display is lit. But the voltage from the transformer may be too low to power the relays. Perform the “Controller Power Input Test,” page 13. If your controller passes the Input Test, perform the “Controller Power Output Test”:

Controller Power Output Test

Is the controller sending voltage to the relay? Test OUT- PUT with a voltmeter:

UNPLUG the kiln/disconnect the power. Remove the 4 screws holding the controller faceplate to the switch box. Lift faceplate out of box and let the controller hang on the outside of the box with the back of the board facing you. Then plug the kiln back in. Program the controller to fire to 1000°F at

FULL rate in Ramp-Hold mode. Press .

Put the voltmeter in DC mode. (It must be in DC mode when testing OUTPUT voltage.) Touch probes to the red wire and black wire connections. Measure voltage when the relay clicks on.

Output Test Result: No voltage at red and black wires The controller is not sending power to the relay. Return

the controller for repair or replacement.

Output Test Result: 10 - 14 v. at red and black wires The controller is sending correct power to the relay. Un-

plug kiln/disconnect power. Remove the kiln switch box. Look for disconnected wires between the controller, relay and elements. Check the wiring diagram to be sure wires are connected to the correct terminals. Be sure connections are tight. If the wiring is okay, replace the relay.

Note: To replace relay, see your kiln’s instruction and service manual.

14 Single-Speed/Ramp-Hold

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Sentry Industries Sentry Xpress 4.0 manual Problem Controller display turns on. No heat in kiln