York ECO R-22 User Manual

Contents

York ECO R-22 User Manual Manual pdf 54 page image

YORK INTERNATIONAL54ControlsCONTROL SEQUENCES COMMON TO ALL UNITSGENERALThe control system for the YORK eco² Packaged Roof-top Unit is fully self-contained and based around anOptiLogic ™ rooftop unit controller. To aid in unit setup,maintenance, and operation, the OptiLogic™ rooftop unitcontroller is equipped with a user interface that is basedaround a 4 line x 20 character backlit LCD display. TheLCD displays plain language text in a menu-driven for-mat to facilitate use. In addition to the display, theOptiLogic ™ user interface is also equipped with an LEDindicator light, which will warn of any abnormal opera-tion of the equipment or communication failures.For the maximum in system flexibility, the YORK eco²Packaged Rooftop Unit can be operated by either a typi-cal 7-wire thermostat (2 cool/2 heat), a space tempera-ture sensor, or stand-alone (VAV only). Note, a fieldwiring terminal block is provided to facilitate unit setupand installation.In lieu of the hard-wired control options, the OptiLogic™rooftop unit controller can be connected to and oper-ated by a Building Automation System (BAS). If required,the OptiLogic™ rooftop unit controller can be equippedwith an optional BACNet IP communication card, whichallows communication, via Ethernet, to a BACNet IPbased BAS.UNOCCUPIED / OCCUPIED SWITCHINGDepending on application, the unit can be indexed be-tween unoccupied and occupied modes of operationby one of three methods, hard-wired input, internal timeclock, or BAS. A contact-closure input is provided forhard-wiring to an external indexing device such as acentral time clock, thermostat with built in scheduling,or a manual switch. The unit controller is also equippedwith a built in 7-day time clock which can be used, inlieu of the contact closure input, to switch the unit be-tween Unoccupied and Occupied modes of operation.The internal time clock is fully configurable via the userinterface and includes Holiday scheduling. In additionto the hard-wired input or the internal time clock, theunit can also be indexed between unoccupied and oc-cupied modes of operation via a BAS command.Note a unit operated from a space sensor can beequipped to temporarily override an unoccupied modeof operation. This Unoccupied Override feature is fullyconfigurable via the OptiLogic ™ user interface.GAS HEATING OPERATIONUnits supplied with gas heat can be equipped one, two,or three independently operated burner modules. Eachmodule is fully self-contained furnace with all neces-sary ignition controls, safeties, and gas valves. TheOptiLogic rooftop unit controller determines how thefurnaces are started and stopped and prevents furnaceoperation if the Supply Fan airflow is not sufficient or ifthe Supply Air Temperature is excessively high.If a furnace module receives a signal to start from theOptiLogic controller, the ignition control engages thefurnace inducer (draft) fan for a 30-second pre-purgecycle. At the end of the 30-second pre-purge, the igni-tion control will stop the furnace and allows the inducerfan to operate for a 30-second post-purge. Each fur-nace contains a direct spark ignition system and in-cluded safeties for flame and inducer fan verification,high temperature and flame roll-out.MORNING WARM-UPMorning Warm-Up can be initialized by BAS or by theOptiLogic controller if the Internal Scheduling is used.If the Internal Scheduling is used, the Morning Warm-Up start time is calculated through an adaptive algo-rithm, which determines the optimum start time.When Morning Warm-Up is required, the OptiLogiccontroller starts the Supply Fan and qualifies the Re-turn Air Temperature for 5 minutes. The internal heatsource (Gas, HW/Steam, or Electric) is controlled tomaintain the Return Air Temperature to the MorningWarm-Up Setpoint, Morning Warm-Up ends when oc-cupancy occurs (BAS, Internal Scheduling, or contactclosure), or when the Maximum Morning Warm-UpTime has expired.