EVOLUTION CONTROLLED LOW AMBIENT COOLING
NOTE: When this unit is operating below 55_F (13°C) outdoor temperature, provisions must be made for low ambient operation. This unit is capable of low ambient cooling down to 0_F (-18°C). ONLY when using the Evolution control. A low ambient kit is not required, and the outdoor fan motor does not need to be replaced for Evolution controlled low ambient operation. Low ambient cooling must be enabled in the UI set-up.Fan may not begin to cycle until about 40_F (4°C).OAT. Fan will cycle based on coil and outdoor air temperature. Evolution controlled low ambient mode operates as follows:
SIn high stage, fan is off when outdoor coil temp is <outdoor air temperature plus 3_F (1.7_C) or outdoor fan has been ON for 30 minutes. (Fan is turned off to allow refrigerant system to
stabilize.)
S In low stage, fan is off when outdoor coil temp is <outdoor air temperature plus 1_F (.6_C) or outdoor fan has been ON for 30 minutes. (Fan is turned off to allow refrigerant system to stabilize.)
SIn high stage and low stage, fan is on when outdoor coil temp > outdoor air temperature plus 25_F (13.8_C) or outdoor coil temp > 80_F (27_C) or if outdoor fan has been OFF for 30 minutes. (Fan is turned on to allow refrigerant system to stabilize.)
SLow-pressure switch is ignored for first 3 minutes during low ambient start up. After 3 minutes, if LPS trips, then outdoor fan motor is turned off for 10 minutes with the compressor running. If LPS closes within 10 minutes then cooling continues with the outdoor fan cycling per the coil temperature routine listed above for the remainder of the cooling cycle. If the LPS does not close within 10 minutes, then the normal LPS trip response (shut down cooling operation and generate LPS trip error) will occur.
DEHUMIDIFICATION MODE
This Evolution system can be used to dehumidify the living space. See UI Installation Instructions for more details.
SEQUENCE OF OPERATION-GAS HEAT
NOTE: Evolution control must be grounded for proper operation or control will lock out.
NOTE: If a power interruption occurs during a call for heat, the control will start a 90-second blower only ON period two seconds after power is restored, if the UI is still calling for gas heating. The amber LED light will flash code 12 during the 90-second period, after which the LED will be ON continuously, as long as no faults are detected. After the 90-second period, the unit will respond to the UI normally.
GAS HEAT MODE AND ADJUSTMENTS
When the UI calls for gas heat, the Evolution furnace board performs a self-check, verifies the pressure switch is open, and starts the inducer on high speed.
1.Inducer Pre-purge Period: When the inducer motor comes up on high speed, the pressure switch closes, and the Evolution ignition control on the furnace board begins a 15 second pre-purge period. If the pressure switch fails to remain closed, the inducer will remain running. After the pressure switch re-closes, the Evolution ignition control will begin a 15 second pre-purge period.
2.Trial-For-Ignition Sequence: The spark igniter will spark for 3 seconds. The main gas valve relay contact closes to energize the gas valve on low stage. After 5 seconds, the igniter is de-energized and a 2-second flame-proving
period begins. NOTE: The unit always lights on high speed inducer and low stage gas valve operation.
3.Flame-Proving: When the burner flame is proved at the flame-proving sensor, the furnace control determines what heating stage to run based on feedback from the UI. If the UI is asking for low stage gas heat, the ignition control will change the inducer speed to low speed and keep the gas valve energized on low stage. If the UI is asking for high stage gas heat, the ignition control will maintain running the inducer on high speed and energize the gas valve’s high stage relay to increase gas flow.
If the burner flame is not proved within 2 seconds, the control will close the gas valve and repeat the ignition sequence up to 3 more Trials-For-Ignition before going to Ignition-Lockout. Lockout will reset automatically after 3 hours, by momentarily interrupting 230 VAC power, or by interrupting 24 VAC power at SEC1 or SEC2 to the furnace board.
If flame is proved when there should be no flame present, control will lock out of Gas-Heating mode and operate the inducer motor until flame is no longer proved.
4.Blower-On Delay: If the burner flame is proven, approximately 37 seconds after the gas valve is opened the Indoor Blower is turned on to the appropriate speed for the gas heating stage.
Simultaneously, the humidifier terminal HUM and electronic air cleaner terminal EAC-1 are energized throughout the heating cycle.
NOTE: EAC-2 terminal is common with L2 and will have 115VAC-to-ground when unit is powered.
5.Blower-Off Delay: When the call for gas heat is satisfied, the gas valve is de-energized, stopping the flow of gas to the burners, and de-energizing the HUM terminal. The inducer motor will remain on for a 4-second post-purge period. The indoor blower and air cleaner terminal EAC-1 will remain energized for 90, 120, 150, or 180 seconds (depending on selection of blower-off delay selected in the UI). The factory-set default is 120-second blower-OFF delay.
CHECK GAS INPUT (NATURAL GAS)
!CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in component damage.
Do not redrill an orifice. Improper drilling (burrs, out-of-round holes, etc.) can cause excessive burner noise and misdirection of burner flame. If orifice hole appears damaged or it is suspected to have been redrilled, check orifice hole with a numbered drill bit of correct size.
!WARNING
FIRE HAZARD
Failure to follow this warning could result in personal injury, death and/or property damage.
DO NOT bottom out gas valve regulator adjusting screws. This can result in unregulated manifold pressure and result in excess overfire and heat exchanger failures.
