White Rodgers 1F98EZ-1621 Emerson Blue Wireless Easy Install Thermostat System Installation Instruction

White-Rodgers is a division 
of Emerson Electric Co.

The Emerson logo is a  
trademark and service mark 
of Emerson Electric Co.

Module has power

Supply voltage is present at module terminals

Comfort Interface en-
ergizing “Y” terminal 
to call for cool but the 
compressor is not run-
ning

1. Compressor protector is open. Check high head pressure and compressor supply 

voltage.

2. Check for open unit power disconnect, circuit breaker or fuses, low pressure switch 

if present in system or Compressor contact or has failed open.

3. Broken wire or connector not making contact.

1

Long Run Time 
Compressor is running 
extremely long run 
cycles

1. Low refrigerant charge.

2. Evaporator blower is not running. Check blower relay, blower motor capacitor, 

motor failure or blockage, wiring and connectors, blower control board, Comfort 
Interface wiring for open circuit.

3. Evaporator coil is frozen. Check for low suction pressure, low Comfort Interface 

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5. Check Comfort Interface sub-base or wiring for short circuit, Comfort Interface 

installation (location, level)

6. Faulty TXV (Thermostatic Expansion Valve). Check TXV bulb installation (size, 

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2

System Pressure Trip 
Discharge or suction 
pressure out of limits or 
compressor overloaded

1. High head pressure. Check high pressure switch if present in system, overcharge 

with refrigerant, non-condensable in system.

2. Condenser coil poor air circulation (dirty, blocked, damaged)

3. Condenser fan not running. Check fan capacitor, wiring and connectors, motor for 

failure or blockage.

4. Return air duct has substantial leakage

5. If low pressure switch present in system, check Flash Code 1 information.

3

Short Cycling 
Compressor is running 
 # >

1.  Comfort Interface demand signal is intermittent

2.  Time delay or control board defective

3.  If high pressure switch present go to Flash Code 2 information

4.  If low pressure switch present go to Flash Code 1 information

4

Locked Rotor

1.  Run capacitor has failed.

2.  Low line voltage (contact utility if voltage at disconnect is low) check wiring. 

3.  Excessive liquid refrigerant in compressor. Compressor bearings are seized, 

measure compressor oil level.

5

Open Circuit

1. Open Outdoor unit power disconnect, circuit breaker, fuse(s). Compressor 

contactor failed to open. Check wiring on compressor contactor and between 
supply and compressor, contactor failure (burned, pitted), low pilot voltage at 
compressor contactor coil.

2. High pressure switch is open and requires manual reset.

3. Unusually long compressor protector reset time due to extreme ambient 

temperature.

4.  Compressor windings are damaged. Check compressor motor winding resistance.

6

Open Start Circuit 
Current only in run 
circuit

1. Run capacitor has failed.

2. Open circuit in compressor start wiring or connections. Check wiring and 

connectors between supply and the compressor “S” terminal.

3. Compressor start winding is damaged. Check compressor motor winding resistance.

7

Open Run Circuit 
Current only in start 
circuit

1. Open circuit in compressor run wiring or connections. Check wiring and connectors 

between supply and the compressor “R” terminal. 

2. Compressor run winding is damaged. Check compressor motor winding resistance.

8

Welded Contactor 
Compressor always runs

1. Compressor contactor has failed closed

2. Comfort Interface demand signal not connected to module

9

Low Voltage Control 
Circuit < 

17 VAC

1. Control circuit transformer is overloaded

2. Low line voltage (contact utility if voltage at disconnect is low). Check wiring 

connections

Control circuit voltage 
too low for operation

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Note: This is only applicable for systems featuring 3  (or similar) technology.