Carrier WeatherExpert 48N2 Controls, Start-up, Operation, Service And Troubleshooting Instructions

Also see for WeatherExpert 48N2: Installation instructions Installation instructions Controls, start-up, operation, service, and troubleshooting Installation instructions

Contents

Carrier WeatherExpert 48N2 Controls, Start-up, Operation, Service And Troubleshooting Instructions Manual pdf 32 page image

32Actuators — In the AC.T.C sub-menu, it will be possibleto control and calibrate actuators. Calibration is a mode inwhich the actuator moves from 0% to the point at which theactuator stalls, and it will then use this angular travel range asits "control angle." It will also be possible to view the "controlangle" adopted by the actuator after a calibration.Within this sub-menu, the user may calibrate and control thethree economizer actuators (2 outdoor air and 1 return air), hy-dronic/steam or humidifier actuators.NOTE: Once a calibration has been started, the user cannotexit test mode or select any other test mode operation untilcomplete.Humidi-Mizer® System — In the Humidi-MiZer(HMZR) sub-menu, it will be possible to control and calibratethe Humidi-MiZer modulating valves (gas bypass and con-denser) while the unit's compressors are OFF. Calibration is amode in which the unit software will first over-drive eachvalve completely shut and to establish the "zero" open posi-tion. The controller then keeps track of the valve's position fornormal operation. During this calibration phase, a light ratchet-ing sound may be heard and will serve as proof of valve opera-tion and closure. Note that the calibration feature in ServiceTest is only provided as an additional troubleshooting tool.This is to ensure that the valve will automatically go throughthe calibration process anytime the unit is powered down, unitpower is cycled, or anytime there is a loss of communicationbetween the EXV board and the valve. There should be noneed to manually calibrate the valves under normal circum-stances.This sub-menu also allows manual manipulation of RHV(reheat 3-way valve), the bypass valve, and condenser valve.With the compressors and outdoor fans off, the user shouldhear a light ratcheting sound during movement of the twomodulating valves. The sound can serve as proof of valveoperation.Service TestHMZRRHV (Humidi-MiZer 3-Way Valve)— On Humidi-MiZer equipped units, this item allows the userto switch the reheat valve from ON to OFF or OFF to ONwhen compressors are in the OFF position. When RHV isswitched to the ON position, the three-way valve will be ener-gized. When RHV is switched to the OFF position, the three-way valve will be deenergized. To exercise this valve with aCircuit B compressor commanded ON, go to (Service TestCOOLRHV). To view the actual valve position at any time,the user can use the Outputs menu (OutputsCOOLRHV).Service TestHMZRC.EXV (HMV-1: Condenser EXVPosition) — On Humidi-MiZer equipped units, this item al-lows the user to exercise the valve that controls flow to the Cir-cuit B condenser. The valve default position is 100% (com-pletely open). The user will be able to adjust the valve from 0to 100% through this function. As confirmation that the valveis operational, the user should hear a light ratcheting sound asthe valve opens and closes. Note that this function is only oper-ational when Circuit B compressors are OFF. To exercise thisvalve with a Circuit B compressor commanded ON, go to(Service TestCOOLC.EXV). To view the actual valveposition at any time, the user can use the Outputs menu (Out-puts COOLC.EXV).Service TestHMZRB.EXV (HMV-2: Bypass EXVPosition) — On Humidi-MiZer equipped units, this item al-lows the user to exercise the valve that controls discharge gasbypass around the Circuit B condenser. The valve default posi-tion is 0% (completely closed). The user will be able to adjustthe valve from 0 to 100% through this function. As confirma-tion that the valve is operational, the user should hear a lightratcheting sound as the valve opens and closes. Note that thisfunction is only operational when Circuit B compressors areOFF. To exercise this valve when a Circuit B compressor isON, go to (Service TestCOOLB.EXV). To view theactual valve position at any time, the user can use the Outputsmenu (OutputsCOOLB.EXV).Service TestHMZRC.CAL (Condenser EXV Calibrate)— On Humidi-Mizer configured units, this item allows theuser to calibrate the valve that controls flow to the Circuit Bcondenser. Switching C.CAL to ON will instruct the unit soft-ware to over-drive the valve in the closing direction. This is toensure that the valve is completely shut and to establish the"zero" open position. The controller then keeps track of thevalve's position for normal operation. During this calibrationphase, a light ratcheting sound may be heard and will serve asproof of valve operation and closure. Note that the calibrationfeature in Service Test is only provided as an additional trou-bleshooting tool. The valves will automatically go through thecalibration process anytime the unit is powered down, unitpower is cycled, or anytime there is a loss of communicationbetween the EXV board and the valve. There should be noneed to manually calibrate the valves under normal circum-stances.Service TestHMZRB.CAL (Bypass EXV Calibrate) —On Humidi-Mizer configured units, this item allows the user tocalibrate the valve that controls discharge gas bypass aroundthe Circuit B condenser. Switching B.CAL to ON will instructthe unit software to over-drive the valve in the closing direc-tion. This is to assure that the valve is completely shut and toestablish the "zero" open position. The controller then keepstrack of the valve's position for normal operation. During thiscalibration phase, a light ratcheting sound may be heard andwill serve as proof of valve operation and closure. Note that thecalibration feature in Service Test is only provided as an addi-tional troubleshooting tool. The valves will automatically gothrough the calibration process anytime the unit is powereddown, unit power is cycled, or anytime there is a loss of com-munication between the EXV board and the valve. Thereshould be no need to manually calibrate the valves under nor-mal circumstances.Cooling — The cooling sub-menu offers many differentservice tests.• Service TestCoolE.POS (Econo Damper CommandPos). It is possible to manually move the actuator duringthe cooling test mode at all times, regardless if econo-mizer cooling is suitable or not.• Service TestCOOLSP.SP (Static Pressure SetPoint). Upon entering the cooling sub-menu, the staticpressure control item will default to the unit's static pres-sure set point. Thereafter, as mechanical cooling com-mences and the fan starts, the static pressure can bemanually adjusted during the cool mode without affect-ing the configured set point for normal runtime opera-tion. By adjusting the static pressure set point, the usercan increase or decrease the supply airflow. Do not use astatic pressure that will exceed the system limits.• Service TestCOOLCL.ST (Requested Cool Stage).If this item is set to a non-zero value, the currentassigned compression stage for this unit will be selectedand enacted. Thereafter, the individual compressor willbe “read-only” and reflect the current staging state. Inaddition, this item will automatically clamp the coolingstages to its pre-configured maximum.• Manual relay control of individual compressors. If thecooling stage pattern request is set to zero, the user willhave the ability to manually control compressors. If theuser energizes mechanical cooling, the supply fan andthe outdoor fans will be started automatically. Duringmechanical cooling, the unit will protect itself. Compres-sor diagnostics are active, monitoring for high dischargepressure, low suction pressure, etc. The user can alsoturn the minimum load valve on and off and set the digi-tal scroll capacity (on units equipped with this device).