Carrier WEATHERMAKER 48/50AJ Operation And Service Manual

Also see for 48AJ: Installation, Start-Up and Service Instructions Installation instructions Started guide Operating and service guide

Contents

33Table 42 — Operating Modes Display TableSupply Air Reset (SA.R) — This variable displays if the sup-ply air reset is currently active. This applies to cooling only.Demand Limit in Effect (DMD.L) — This variable displaysif the mechanical cooling capacity is currently being limited orreduced by an outside third party.Temperature Compensated Start (T.C.ST) — This variabledisplays if Heating or Cooling has been initiated before theoccupied period to pre-condition the space.IAQ Pre-Occupancy Purge Active (IAQ.P) — This variabledisplays if the economizer is open and the fan is on to pre-ventilate the building before occupancy.Linkage Active CCN (LINK) — This variable displays if alinkage master in a zoning system has established “linkage”with this air source (rooftop).Mechanical Cooling Locked Out (LOCK) — This variabledisplays if mechanical cooling is currently being locked due tolow outside air temperature.HVAC Mode Numerical Form (H.NUM) — This is a numer-ical representation of the HVAC modes which may be read viaa point read.SYSTEM MODES (Operating ModesSYS.M)System Mode Off — When the system mode is OFF, all out-puts are to be shut down and no machine control is possible.The following list displays the text assigned to the SystemMode when in the OFF mode and the conditions that maycause this mode are checked in the following hierarchal order:1. Wake up timer on a power reset.(“Initializing System ...”)2. System in the process of shutting down compressors andwaiting for timeguards to expire.(“Shutting Down ...”)3. Factory shut down (internal factory control level —SHUTDOWN).(“Factory Shut Down”)4. Unit stop (software application level variable that acts asa hard shut down — Service TestSTOP).(“Local Machine Stop”)5. Fire shut down (traumatic fire shutdown condition basedon the Fire Shutdown Input — InputsFIREFSD).(“Fire-Shutdown Mode”)6. Emergency stop, which is forced over the CCN throughthe Emergency Stop Variable (EMSTOP).(“CCN Emergency Stop”)7. Startup delay.(“Startup delay = 0-900 secs”)8. Service test ending transition timer.(“Service Test Ending”)9. Unexplained internal software failure.(“Internal Failure”)System Mode Test — When the system mode is Test, the con-trol is limited to the Test mode and is controllable via the localdisplays (scrolling marquee and Navigator™ display) orthrough the factory service test control. The System Testmodes are Factory Test Enabled and Service Test Enabled. Seethe Service Test Mode section for details on test control in thismode.1. Factory Test mode(“Factory test enabled”)2. Service Test mode(“Service test enabled”)System Mode Run — When the system mode is Run, the soft-ware application in the control is free to run the HVAC controlroutines by which cooling, heating, IAQ, etc., is possible. Thereare two possible text displays for this mode, one is normal runmode and the other occurs if one of the following fire-smokemodes is present: smoke purge, pressurization or evacuation.1. Normal run time state(“Unit Operation Enabled”)2. Fire-Smoke control mode(“Fire-Smoke Control”)HVAC MODES (Operating ModeHVAC) — The systemmode must be selected before the unit controls can select theHVAC mode of the rooftop unit. The selection of an HVACmode is based on a hierarchal decision making process. Certainoverrides may interfere with this process and the normal tem-perature/humidity control operation of the unit. The decisionmaking process that determines the HVAC mode is shown inFig. 4 and Appendix D.Each HVAC Mode is described below. The HVAC modenumber is shown in parenthesis after the mode.HVAC Mode — STARTING UP (0) — The unit is transi-tioning from the OFF mode to a different mode.HVAC Mode — DISABLED (1) — The unit is shut downdue to a software command disable through the scrolling mar-quee, a CCN emergency stop command, a service test end, or acontrol-type change delay.HVAC Mode — SHUTTING DOWN (2) — The unit is tran-sitioning from a mode to the OFF mode.HVAC Mode — SOFTSTOP REQUEST (3) — The unit isoff due to a soft stop request from the control.HVAC Mode — REM SW.DISABLE (4) — The unit is offdue to the remote switch.HVAC Mode — FAN STATUS FAIL (5) — The unit is offdue to failure of the fan status switch.HVAC Mode — STATIC PRESSURE FAIL (6) — The unit isoff due to failure of the static pressure sensor.HVAC Mode — COMP.STUCK ON (7) — The unit is shutdown because there is an indication that a compressor is run-ning even though it has been commanded off.HVAC Mode — OFF (8) — The unit is off and no operatingmodes are active.HVAC Mode — TEST (9) — The unit is in the self test modewhich is entered through the Service Test menu.HVAC Mode — TEMPERING VENT (10) — The econo-mizer is at minimum vent position but the supply-air tempera-ture has dropped below the tempering vent set point. Stagedgas heat is used to temper the ventilation air.HVAC Mode — TEMPERING LOCOOL (11) — The econ-omizer is at minimum vent position but the combination of theoutside-air temperature and the economizer position hasdropped the supply-air temperature below the tempering coolset point. Staged gas heat is used to temper the ventilation air.ITEM EXPANSION RANGE CCN POINTSYS.M ascii string n/aHVAC ascii string n/aCTRL ascii string n/aMODE MODES CONTROLLING UNITOCC Currently Occupied ON/OFF MODEOCCPT.OVR Timed Override in Effect ON/OFF MODETOVRDCV DCV Resetting Min Pos ON/OFF MODEADCVSA.R Supply Air Reset ON/OFF MODESARSDMD.L Demand Limit in Effect ON/OFF MODEDMLTT.C.ST Temp.Compensated Start ON/OFF MODETCSTIAQ.P IAQ Pre-Occ Purge Active ON/OFF MODEIQPGLINK Linkage Active — CCN ON/OFF MODELINKLOCK Mech.Cooling Locked Out ON/OFF MODELOCKH.NUM HVAC Mode Numerical Form number MODEHVAC