Keating Of Chicago 028951 service manual Troubleshooting The Thermostat

TROUBLESHOOTING THE THERMOSTAT
Temperature reading is incorrect,		• Sensor or controller may be bad.	Place a jumper wire across the
showing a sensor error,	or	Sensor connections may be bad.	thermocouple input terminals. The
LOAD LED is switching at the			display should indicate ambient
wrong temperature.			temperature. If it does, the
			controller is ok. If not, replace
			controller.
			Decrease set point below ambient
			temperature, LOAD LED should be
			off for heating controllers. If it is, the
			controller is OK.
			Increase set point above ambient
			temperature. LOAD LED should be
			on for heating controllers. If it is, the
		• Controller is wired incorrectly.	controller is OK.
			Verify proper wiring. Call 1-800-
			KEATING for a diagram.
Temperature reading is decreasing,		• Thermocouple polarity is reversed.	Check thermocouple connections.
but actual temperature is increasing.		Red wire denotes negative wire.	All connections, including extension
			wire, must maintain the correct
			polarity. Correct if needed.
		• Ambient temperature in the control	Measure temperature in cabinet to
		cabinet is over 70°C.	ensure it is below 70°C.

For troubleshooting the thermocouple, use the chart below

Temperature (°F)	Resistance (Ohm)
95	0.30
100	3.80
125	4.60
150	5.50
175	6.40
200	7.90
225	8.40
250	9.70
275	10.90
300	12.40
325	13.80
350	15.10
375	17.00
400	18.40
425	20.20
450	21.30
475	23.30

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