Erratic Temperature Readings; Overfire; Stuck Display; Relay Chatters Or Buzzes - Paragon DTC 1000 Operation & Maintenance Instructions Manual

Erratic Temperature Readings

Problem:
Probable Causes:
Thermocouple Lead Wires Attached to Wrong Terminals or Too
Close to Other Wires
Thermocouple Lead Wires Touch at Bare Ends
Electrical Noise
Poor Electrical Circuit Ground
Defective Relay or Transformer
Defective Thermocouple
Thermocouple Touching Metal Case of Kiln
Even though protected by insulation, the thermocouple
wires are sensitive to electromagnetic waves. Position them
away from other wires inside the switch box. Thermocouple
wires must be attached to the correct terminals. Check that
the thermocouple wire ends are separated where the insula-
tion has been stripped. Electrical "noise" from a chattering re-
lay or nearby arc welding machines can cause erratic readings.
If erratic temperatures display momentarily each time the
relays click on, have an electrician check the electrical circuit
for a poorly connected grounding wire.
If the erratic temperture readings display only while the el-
ements are powered, the problem may be a defective relay or
transformer.
A worn thermocouple can cause erratic temperature read-
ings. Wiggle the thermocouple tip. If the temperature jumps
by a wide margin, replace thermocouple.

Overfire

Problem:
Probable Causes:
Thermocouple Pushed Out of Firing Chamber
Stuck Relay
Defective Thermocouple
Thermocouple Touching Metal Case of Kiln
(Ceramics: use witness cones.) Check that the thermocou-
ple is protruding into the firing chamber by at least
Sometimes bumping a shelf against the thermocouple pushes
it out of the firing chamber, altering the temperature readings.
If an element stays on after pressing STOP , a relay is stuck.
Replace the relay. If the temperature reading is over 100°
higher than the actual temperature, replace the thermocouple.
Note: a defective thermocouple can read correct room tem-
perature and be inaccurate at high temperatures.
Make sure the thermocouple, including the spring on the
end of the thermocouple, is not touching the kiln's metal case.

Stuck Display

Problem:
Probable Causes:
Stuck Key
Electrical Noise
Sometimes a chattering relay or other source of electrical
noise freezes the display message. Turn off the power for ten
seconds. If that does not correct the problem, return the board
for servicing.
20
Problem:
Probable Causes:
Voltage at controller board connectors 3 and 6 should be 12
- 14 volts DC. Voltage in the 10 - 11 range may not be enough to
drive the relays, or may cause a relay to chatter. See "Controller
Display Lights Up Normally, Some or All Heating Elements
Do Not Fire," page 16, to check the board with a voltmeter.
Low voltage at connectors 3 and 6 can be caused by a defec-
tive transformer, a defective transistor on the board, or low line
voltage. To diagnose the cause, check the voltage from the
transformer at connectors 5 and 7. Correct voltage is 20 - 24
volts AC. When voltage falls below 20 volts, the board will mal-
function or will not have enough voltage to drive the relays.
If low voltage is detected at connectors 3 and 6 or 5 and 7, re-
place the transformer.
Problem:
Probable Causes:
Check the fuse in the kiln's switch box. The fuse holder is
near the bottom of the switch box. Remove fuse by pressing on
the fuse holder and turning counter-clockwise half a turn.
The correct fuse:
Refer to the diagram on page 22. Disconnect the orange,
white and black wires (#5, 6, 7) from the back of board. Apply
" - ".
1 5
2 8
power to kiln. If fuse blows, replace the transformer. If the fuse
does not blow, then the problem is a board or relay.
Connect #5, 6 and 7 wires to the board again. Disconnect
red wire, #3. Apply power. If the fuse blows, replace or service
the board. If the fuse does not blow, the problem is caused by a
short in the coil of a relay.
Disconnect each relay, one at a time, until you find the relay
that blows the fuse.
Problem:
Cause:
When the controller emits a beeping sound at the begin-
ning of firing, the alarm was probably set to 0000 or a tempera-
ture below room temperature. See "Temperature Alarm,"
page 13.

Relay Chatters or Buzzes

Defective Transformer
Defective Transistor on Controller
Low Line Voltage
Weak Relay
Kiln Switch Box Fuse

Blows Repeatedly

Wrong Fuse
Defective Transformer
Shorted Relay
Defective Controller
AGC ½ A 250V AC

Unwanted Beeping Sound

Alarm Set to 0000