Carrier 50PG20-28 Controls, Start-up, Operation, Service And Troubleshooting Instructions

Also see for 48PG20---28: User's information manual User's information manual Installation and service instructions

Carrier 50PG20-28 Controls, Start-up, Operation, Service And Troubleshooting Instructions Manual pdf 49 page image

\ \\\\\_\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\8 PLACES ON 020 0__9 PLACES O_ 628_s Et_CHS_EFig. 10- Wind Baffle DimensionsIndoor Air Quality (IAQ) -- The (7omfbrtLinkTM con-trol has the capability for several methods of demand ventila-tion control, hldoor air quality is typically measured using aCO2 sensor whose measurelnents are displayed in parts per mil-lion (ppm). Outdoor air quality may be measured with a CO2sensor for indoor-outdoor differential demand ventilationcontrol, or with other sensor types for the outdoor air lockoutfunction. The factory-installed indoor air quality CO2 sensor ismounted in the return section. A field-installed indoor airquality CO2 sensor may be mounted in the retum or directly inthe occupied space, per job requirements. The indoor air qualitymodes of operation can be afl_cted by configurations for iMoorair quality sensor (Conftguration-+AIR. Q-+IA. CF), indoor airquality switch ((bnfiguration-+AIR.Q-+IZCF), outdoor airquality sensor (Configuration-+AIR.Q_OA.CF) and otherrelated fan madlimit configurations as described below.IAQ (Analog Input) The ComfbrtLink TM control is config-ured tbr indoor air quality sensors which provide 4 to20 mA for 0 to 2000 ppm. If a sensor has a diflhent range,the ppm display range must be reconfigured by entering newvalues for (bnfiguration-+AIR.Q-+L4M and (bnfigura-tion -+AIR. Q -+L2OM.IA. (T = 0 (No IAQ) IA. (T = 0 signifies that there isno IAQ sensor installed. The damper will operate at theConfigumtion-+AIR.Q-+ECMN position when the space isoccupied and the indoor t_aaais on.1A. CF = 1 (DCV) When Lt.(T = 1, the IAQ algoritban isset tbr Demand Control Ventilation (DCV). During DCV, thedamper modulates between two user confignrations dependingupon the relationship bewveen the IAQ and the Outdoor AirQuality (OAQ). The lower of these two positions is referred toas the Minimmn IAQ Damper Position (Configuration-+AIR.Q-+AQ.MN) while the higher is referred to as Econo-mizer Minhnum Position (ECMN). The AQ.MN should be setto an economizer position that brings in enough fiesh air torelnove contaminants and CO 2generated by sources other thanpeople. The ECMN should be set to an economizer positionthat brings in enough flesh air to remove contaminants andCO2 generated by all sources including people. The ECMNvalue is the design value for maximum occupancy.The ComJbrtLink control will begin to open the dampertiom the AQ.MNposition when the IAQ level begins to exceedthe Outdoor Air Quality (OAQ) level by a configurablemnount. This amount is referred to as AQ Differential Low((bnfiguration-+AIR.Q-+AQD.L). When the differentialbetween IAQ and OAQ reaches AQ Differential High((bnfiguration-+AIR.Q-+AQD.H), the economizer positionwill be ECMN. When the IAQ/OAQ difl'erential is betweenAQD.L and AQD.H, the control will modulate the damperbewveen AQ.MN and EC.MN in a linear manner as shown inFig. 11. The damper position wilt never exceed the boundsspecified by AQ.MN and EC.MN during IAQ control.IA.(T = 2 (Override IAQ) When IA.(T = 2, the IAQalgorithm maintains the damper at (bnfiguration-+AIR.Q-+ECMN until the override condition triggers. Theoverride triggers when the IAQ/OAQ differential is reeaterthan Configumtion-+AIR.Q-+AQD.H. The override positionis Configuration-+AIR.Q_OVR.P (Economizer OverridePosition). The economizer position will return to ECMNwhen the IAQ/OAQ differential is less than (bnfiguration-+AIR. Q-+A QD.L .The Override algorithm will operate whenever the buildingis occupied and the indoor tan is operating or whenever theIAQ algoritban has caused the indoor tan to operate. Theconfiguration IA.FN determines whether or not the IAQ atgu-rithm can turn on the indoor fan.If the indoor tan is not operating, the economizer positionwill be zero. If the oven-ide is not active and the buildingis unoccupied, the economizer position will be zero.The damper position may exceed (bnfigumtion-+AIR.Q49