ENVISION SERIES INSTALLATION MANUAL
Microprocessor Control (cont.)
Cooling Operation
In all cooling operations, the reversing valve directly tracks the “O” input. Thus, anytime the “O” input is present, the reversing valve will be energized.
Cool, 1st Stage (Y1,O)
The blower motor and hot water pump are started immediately, the loop pump(s) is energized 5 seconds after the “Y1” input is received. The compressor will be energized (on low capacity for Dual Capacity units) 10 seconds after the “Y1” input. The ECM blower will shift from low to medium speed 15 seconds after the “Y1” input (85% of medium speed if in dehumidification mode).
Cool, 2nd Stage (Y1, Y2, O) Single Speed Units
The fan changes to high speed (85% of high speed if in dehumidification mode) 15 seconds after the “Y2” input (ECM only).
Cool, 2nd Stage (Y1, Y2, O) Dual Capacity Units
The second stage compressor will be activated 5 seconds after receiving a “Y2” input as long as the minimum first stage compressor run time of 1 minute has expired. The ECM blower changes to high speed 15 seconds after the “Y2” input (85% of high speed if in dehumidification mode). The Comfort Alert will delay the second stage compressor until 5 seconds after it receives a “Y2” from the board.
Fan (G only)
The fan starts on low speed (PSC ON). Regardless of fan
input “G” from thermostat, the fan will remain on low speed for 30 seconds at the end of each heating, cooling or emergency heat cycle.
Lockout Conditions
During lockout mode, the appropriate unit and thermostat lockout LEDs will illuminate. The compressor, loop pump, hot water pump, and accessory outputs are
Comfort Alert lockouts cannot be reset at the thermostat. All other lockout modes can be reset at the thermostat after turning the unit off, then on, which restores normal operation but keeps the unit lockout LED illuminated. Interruption of power to the unit will reset a lockout without a waiting period and clear all lockout LEDs.
High Pressure
This lockout mode occurs when the normally closed safety switch is opened momentarily (set at 600 PSI).
Low Pressure
This lockout mode occurs when the normally closed low pressure switch is opened for 30 continuous seconds (set at 40 PSI). A low pressure fault may also be indicated when a Comfort Alert lockout has occurred.
Freeze Sensing (Water Flow)
This lockout mode occurs when the freeze thermistor temperature is at or below the selected freeze point (well 30°F or loop 15°F) for 30 continuous seconds.
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