Programmable Electronic Thermostat
(630-0640)                 TroubleShooting            Faxback Doc. # 45265

Because of the simplicity of this programmable thermostat, it will rarely
give you any concern.  If it should fail to function properly, this
section will help you to get the unit back into service quickly.


SYMPTOM:  Thermostat loses program
Procedure:

1. You may have a dead battery.

2. The POWER switch may have been accidentally switched to OFF.


SYMPTOM:  No Display
Procedure:

1. Check to see that the POWER switch is ON.

2. Check main switches, fuses, and circuit breakers on heating equipment
   to make sure it has power.  The heating control circuit powers the
   thermostat even when it is used to control air conditioning equipment.

3. Check the wiring connections to the thermostat.

4. Make sure your system uses 24V AC.  The thermostat will not operate
   on a millvolt system.

5. See symptom below "Display Goes Blank."

SYMPTOM:  Display goes blank before or after a furnace burn cycle.
Procedure:

  Your furnace is interrupting power to the thermostat.  This is not a
  problem.  The 9-volt battery will be adequate to carry the program for
  the entire heating season.

SYMPTOM:  Display goes blank for several minutes during long furnace burn
cycle.  Procedure:

  The furnace is probably not operating properly.  Check for dirty air
  filters or blocked registers.

SYMPTOM:  Incorrect Temperature Display.
Procedure:

  1. Make sure that the thermostat has been on for at least two hours.

  2. Place a room thermometer on the left side of the thermostat.

  3. Open the left door of the thermostat.

  4. Locate the small circular dial (Potentiometer).  See Page 7.

  5. Turn the dial clockwise to increase the indicated temperature, or
     counterclockwise to decrease the indicated temperature.  Each turn
     should be made very slightly.  After each turn, allow the thermostat
     to stabilize for about 30 seconds.

  6. Continue this procedure until the thermostat has the same temperature
     reading as your room thermometer.

SYMPTOM:  Noisy gas valve.

A.  Humming noise with the gas valve not actually opening and closing.
Procedure:
  1. Obtain a 250 ohm 20 watt resistor.

  2. Place the resistor with two terminals on the gas valve.

B. Chattering noise with the gas valve sounding like it is opening and
   closing.
Procedure:

  1. Try the resistor solution in "A" above.

  2. If the gas valve is still noisy, install an isolation relay.
     See ORDER INFORMATION.

SYMPTOM:  Furnace will not turn on.
Procedure:

  First, check to see if your thermostat is operating properly.

  1. With a voltmeter, measure the voltage between the red and white
     terminals for heat (the black and yellow terminals for air
     conditioning).  There should be approximately 24-volts AC when
     heat/air conditioning IS required.  If this drop occurs, your
     thermostat is operating properly, but you need to install an
     isolation relay.  See ORDER INFORMATION.

  2. If the voltage drop does not occur, return the thermostat to your
     place of purchase.

SYMPTOM:  Furnace operates continuously.
Procedure:

  1. Check the thermostat to see if it is wired properly, or check the
     furnace air conditioning system to make sure they are operating
     correctly.

  2. Measure the voltage as described under the previous symptom.

SYMPTOM:  Thermostat will not turn air conditioner on.
Procedure:

  Check the circuit breaker on the air conditioner to make sure it has
  power.

SYMPTOM:  The thermostat will not let me make a temperature setting.

  1. Check if you have already made 6 settings.  A maximum of 6 settings
     per day are available.  The thermostat will not accept a seventh
     setting.

  2. Check if you have used all 8 available temperature combinations.  A
     maximum of 8 heating and cooling combinations is allowed in your
     weekly program.  The thermostat will not accept a ninth combination.

(LB/SM 10/30/97)

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