SEQUENCE OF OPERATION

174065-YIM-A-0206

SEQUENCE OF OPERATION

Cooling

The following sequences of operation are based on using a standard single-stage cooling thermostat.

WITH POWER TO UNIT AND THERMOSTAT IN COOLING MODE.

1.If the fan switch on the thermostat is in the “ON” position, the 24 volts at “G” will energize the “K1" relay on the fan control board, close the ”K1" relay contacts, and energize the indoor blower motor. If the fan switch is in the “AUTO” position, the blower will operate only when there is a call for cooling by the thermostat.

2.On a call for cooling, the thermostat will send 24 volts to “Y” on the fan control board. The 24 volt signal will energize contactor “M1", and power will be supplied to the compres- sor and outdoor fan motor. If the fan switch on the thermo- stat is on the ”AUTO" position, the thermostat will also send a 24 volt signal to “G” on the fan control board and the in- door blower will operate as indicated in step 1.

3.When the demand for cooling has been satisfied, the “M1" contactor will be de-energized when the 24 volt ”Y" signal is removed. If the fan switch on the thermostat is energized when the 24 volt “Y” signal is removed. If the fan switch on the thermostat is in the “ON” position, the indoor blower will continue to run. If the fan switch is in the “AUTO” posi- tion, the 24 volt “G” signal will be removed, and after a

60 second delay, the “K1" relay will open and de- energize the indoor blower motor,

Heating

WITH POWER TO UNIT AND THERMOSTAT IN HEATING MODE.

1.If the fan switch on the thermostat is in the “ON” position, the 24 volts at “G” will energize the “K1" relay contacts, and energize the indoor blower motor. If the fan switch on the thermostat is in the ”AUTO" position, the blower will oper- ate only when there is a call for heating by the thermostat.

2.On a call for heating, the thermostat will send 24 volts to “W1" on the fan control board. The 24 volts signal will ener- gize relay ”K2" on the fan control board, and the first stage of electric heat will be energized.

3.When the heating demand is satisfied, the electric heat will be de-energized when the 24 volt “W1" and ”W2" signals are removed. If the fan switch on the thermostat is in the “ON” position, the indoor blower will continue to run. If the fan switch is in the “AUTO” position, the “K1" relay will open and de-energize the indoor blower motor after the appropri- ate time delay.

Please refer to Table 13 for more information.

TABLE 13 - THERMOSTAT SIGNALS (SINGLE PHASE UNITS)

SIGNAL

STATE

 

ON

“G”

 

 

OFF

 

ON

“G”

 

“Y”

 

 

OFF

 

ON

“G”

 

“W1"

 

 

OFF

 

ON

“G”

 

“W1"

 

”W2"

 

 

OFF

 

 

BOARD FUNCTION

FAN INSTANT ON

FAN INSTANT OFF

FAN INSTANT ON

COMPRESSOR AND OUTDOOR FAN INSTANT ON

COMPRESSOR AND OUTDOOR FAN INSTANT OFF FAN 60 SECOND DELAY OFF

FAN INSTANT ON

HEATER BANK 1 ELEC. HEAT INSTANT ON

HEATER BANK 1 ELEC. HEAT INSTANT OFF FAN 5 SECOND DELAY OFF

FAN INSTANT ON

HEATER BANK 1 ELEC. HEAT INSTANT ON

HEATER BANK 2 ELEC. HEAT 10 SECOND DELAY ON HEATER BANK 3 ELEC. HEAT 20 SECOND DELAY ON

HEATER BANK 1 ELEC. HEAT INSTANT OFF HEATER BANK 2 ELEC. HEAT 12 SECOND DELAY ON HEATER BANK 3 ELEC. HEAT 1 SECOND DELAY ON FAN 6 12 SECOND DELAY OFF

SIGNAL

STATE

ON

“W1"

OFF

ON

”W2"

OFF

ON

“W1"

”W2"

OFF

BOARD FUNCTION

FAN INSTANT ON

HEATER BANK 1 ELEC. HEAT INSTANT ON

HEATER BANK 1 ELEC. HEAT INSTANT OFF FAN 5 SECOND DELAY OFF

FAN INSTANT ON

HEATER BANK 1 ELEC. HEAT 12 SEC. DELAY OFF HEATER BANK 2 ELEC. HEAT INSTANT ON

HEATER BANK 1 ELEC. HEAT 12 SEC. DELAY OFF HEATER BANK 2 ELEC. HEAT INSTANT OFF FAN 5 SECOND DELAY OFF

FAN INSTANT ON

HEATER BANK 1 ELEC. HEAT INSTANT ON

HEATER BANK 2 ELEC. HEAT 10 SECOND DELAY ON HEATER BANK 3 ELEC. HEAT 20 SECOND DELAY ON

STAGE 1 ELEC. HEAT INSTANT OFF

HEATER BANK 2 ELEC. HEAT 12 SECOND DELAY ON HEATER BANK 3 ELEC. HEAT 1 SECOND DELAY ON FAN 6 12 SECOND DELAY OFF

Unitary Products Group

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York D2EB installation instructions Sequence Of Operation, Cooling, Heating