ENVISION CONSOLE INSTALLATION MANUAL
Envision Console Controls
The user selects either “Heat/Cool” or “Fan Only” on the mode switch, then either “High” or “Low” at the fan speed switch. The temperature can be controlled by rotating the thermostat control knob.
Figure 6: Unit Mounted Control
The “Fan Only” setting provides constant fan operation.
In the “Heat” mode, a call for heat by the thermostat closes the compressor contactor contacts, energizing the com- pressor, which will run until the thermostat is satisfied.
In the “Cool” mode, a call for cooling by the thermostat energizes the reversing valve and closes the compressor contactor contacts, energizing the compres- sor, which will run until the thermostat is satisfied.
The emergency electric heat operation in the “Heat/Cool” mode is subject to the setting of the internally mounted mode switch. The optional, factory installed electric heat will operate when the internally mounted mode switch is in the “Emergency Heat” mode. In the “Heat” mode, a call for heating energizes the fan and electric heater contactor, energizing the electric heat elements and fan, which will run until the thermostat is satisfied. When the internally mounted mode switch is in the “Normal/Boilerless” mode the unit operates in its normal “Heat/Cool” operation, unless there is an aquastat controller. When the normally open circuit of the aquastat closes and the unit is in the heating mode, it will switch to the “Emergency Heat” condition until the thermostat is satisfied or the aquastat opens restarting the compressor.
If either the low or high pressure safety switches are opened, the compressor and reversing valve are disabled by the lockout relay. Unit operation will resume only after the voltage to the unit is interrupted or the mode switch is placed in the “Off” position.
If the electric heat limit switches are opened, the electric heat is disabled.
Optional Versatec Microprocessor Control Features
The Versatec microprocessor board provides control of the entire unit as well as outputs for status modes, faults and diagnostics. The control system is a microprocessor- based control board that is located in the unit control box. This feature is available for either unit mounted controls or optional remote wall mounted thermostat. A
Startup
The unit will not operate until all the inputs and safety controls are checked for normal operating conditions.
Fault Retry
All faults are retried twice before finally locking the unit out to prevent nuisance service calls.
Component Sequencing Delays
Components are sequenced and delayed for optimum unit performance.
Short Cycle Protection and Random Start
The control allows a minimum on or off time of 5 minutes for short cycle protection. A random time delay of 0 to
30 seconds is generated after each
Night Setback
A grounded signal to common or connecting 24 VAC to the NS terminal will initiate the night setback mode.
Load Shed
A grounded signal to common or connecting 24 VAC to the LS terminal places the controller into the load shed mode. The compressor will become disabled and the fan will start upon a thermostat call for heating or cooling.
Emergency Shutdown
A grounded signal to common or connecting 24 VAC to the ES terminal places the controller into the emergency shutdown mode. The compressor and fan operation are suspended while in the emergency shutdown mode.
Condensate Overflow Protection
The board incorporates an impedance liquid sensor at the top of the condensate drain pan. Upon a continuous 30- second sensing of the condensate, the cooling operation of the unit is suspended.
Safety Controls
The microprocessor board receives separate signals from a high pressure switch for safety, a low pressure switch to
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