Carrier 50EJQ Technical Information

Controls, Operation, and TroubleshootingCONTROLSPageSAFETY CONSIDERATIONS ... 1GENERAL ... 2Carrier Com

The following qualifying conditions must be met for theCooling Control Submaster Loop to be active:• the indoor fan has been ON for 30 seconds• Heat m

Time Guard Override may also be initiated from CCN bysetting TGO option in SERVICE table from OFF to ON.The random 1 to 63 seconds is also applied to

Submaster Gain is calculated as:SubGain = (OAT − TEMPBAND)/(ESG + 1);SubGain is fixed between ESG and −1. The commandedposition is calculated as:ECONPO

Variable Air Volume Units — Heating control will maintainreturn-air temperature at occupied heat set point under thefollowing conditions:• Units with

Cooling and Heating — Average occupied zone tempera-ture (AOZT) will replace the space temperature (SPT) dur-ing occupied and biased occupied periods

Space Temperature Offset (CV Only) — The con-trol will provide a capability for CV units to offset a spacetemperature by ±5° F, using a T-56 device. T

Table 25 — Indoor-Air Quality InputsINPUTS TYPEEconomizer MinimumDamper PositionUser Configured, default = 20%Fan State Internal ParameterOccupancy Sta

Constant Volume and Modulating Power Ex-haust —The supply fan must be on for the modulatingpower exhaust fan routine to operate. The space temperature

QUALIFYING CONDITIONS — The following conditionsmust be met for Unoccupied Free Cooling to be active:• NTEN option is enabled• Unit is in unoccupied s

SEQUENCE OF OPERATION — The following algorithmis used to determine Pre-Occupancy Purge mode:if (OAT ≥ NTLO and OAT ≤ OCSP and enthalpy is low)then PU

GENERALIMPORTANT: This literature contains controls, op-eration, and troubleshooting data for 48/50EJ, EK, EW,EY rooftop units and 50EJQ, EWQ heat pum

Smoke Control Modes — Variable air volume unitsand CV units with optional expansion I/O board will per-form fire and smoke control. The unit will provi

Base and Expansion Board Modules — Table 44is a map of the type of input and output for each channel andcorresponding terminal for both the base modul

Table 45 — Base Module — CVCHANNEL NO.(TERMINALS)ASSIGNMENTCHANNEL NO.(TERMINALS)ASSIGNMENT1 (T17-T25) Y1 or Remote Start/Stop (Version 1.0) 17 (T26-T

Table 47 — Base Module — VAVCHANNEL NO.(TERMINALS)ASSIGNMENTCHANNEL NO.(TERMINALS)ASSIGNMENT1 (T17-T25) Remote Start/Stop (Version 1.0) 17 (T26-T27) E

Table 49 — DIP Switch Assignments (Software Version 1.0)12 3 4 5 6 7 8OPEN VAVCCN/SENSORSEXPANSIONI/OBOARDFIELDTESTONMODULATEDPOWEREXHAUSTTIME GUARD O

INSTALLATIONControl Wiring —See unit wiring diagram for connec-tions to main control box. The recommended types of con-trol wiring for the 48/50EJ,EK,

RJ11 PLUG WIRING — Units on the CCN can be moni-tored from the space at the sensor through the RJ11 con-nector, if desired. To wire the RJ11 connector

The only VFD adjustment that may need to be made atinstallation is the supply duct static set point. The factoryduct static default value is 30 Hz (Sr

6. Press the READ/WRITE key again to enter the new value.7. At this point a check can also be made of the factorydefault values.NOTE: These values app

Differential is the difference between the turn off point andthe turn on point for each module. Differential is calibratedin terms of percent of input

• control of one stage of gas or electric heat to maintain supply-air temperature at supply-air set point during occupiedperiods• ability to use multi

TROUBLESHOOTINGBy using the Building Supervisor, Service Tool orComfortWorks™ software, actual operating conditions of theunit are displayed in DXCOOL

this fault occurs 3 times within 90 minutes, the compressorwill be locked out and manual reset will be required. To re-set, interrupt power to the con

Table 58 — Unit AlarmsCODE DESCRIPTION LEDBLINKSRESETMETHODACTION TAKENBY CONTROLPROBABLE CAUSEHF_03 SPT Thermistor Failure 7 Automatic Disables unocc

Table 59 — Unit AlertsCODE DESCRIPTION LEDBLINKSRESETMETHODACTION TAKENBY CONTROLPROBABLE CAUSESE_06 Indoor Fan Status None N/A Alert generated Fan st

Table 62 — Controls TroubleshootingSYMPTOMS PROBABLE CAUSE(S) SOLUTION(S)Evaporator fan does not run. Circuit breaker open.Fan contactor inoperative.U

Table 64 — CONFIG Configuration TableNAME FORMAT DESCRIPTION LIMITS DEFAULTURST no/yes Unit Shutdown/Restart 0 to 1 noIAQP hi/lo IAQ Priority Level 0 t

Table 67 — STATUS01 Display TableNAME FORMAT DESCRIPTIONS LIMITSSPT xxx.xF Space Temperature −10 to 245SAT xxx.xF Supply-Air Temperature −10 to 245RAT

Table 69 — DXCOOL Display TableNAME FORMAT DESCRIPTIONCMP1 on/off Compressor 1CMP1SAFE on/off Compressor 1 SafetyCMP2 on/off Compressor 2CMP2SAFE on/o

Table 78 — SERVICE TableNAME FORMAT DESCRIPTION LIMITS DEFAULTIIAQREFL xxxx Indoor AQ Low Ref. 0 to 5000 0IIAQREFH xxxx Indoor AQ High Ref. 0 to 5000

Table 80 — SET POINT TableNAME FORMAT DESCRIPTION LIMITS DEFAULTOHSP xx.xF Occupied Heat Set Point 55 to 80 F 68OCSP xx.xF Occupied Cool Set Point 55

Variable Frequency Drives — The evaporator fan iscontrolled by a variable frequency drive (VFD). The outputthat normally controls the indoor-fan motor

Table 83 — HOLIDEF Defined Holidays TableNAME POINT DESCRIPTION STATUSHOLDY01STHROUGHHOLDY18SHOL-MON Holiday Start Month xxHOL-DAY Holiday Start Day xx

COOLING CAPACITY STAGING TABLESSee Tables 85 - 87 for cooling capacity staging.Table 85 — Constant Volume Units with 2 CompressorsSTAGES 01(Economizer

THERMISTOR RESISTANCE TABLESSee Tables 88 and 89 for thermistor resistance versus temperature values.Table 88 — Thermistor Resistance Vs Temperature V

Table 89 — Thermistor Resistance Vs Temperature Values forSpace Temperature Thermistors T-55 and T-56 (10 K at 25 C Resistors)TEMP(F)RESISTANCE(Ohms)T

Copyright 1998 Carrier CorporationManufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and w

Sequence of Operation (Expansion Module) —For CV, VAV, or heat pump units equipped with optional ex-pansion I/O (input/output) board, the following fu

SPACE SENSORCONTROL,CLOSE DIP-SWITCHDIP-SWITCH#7CLOSEDTHERMOSTATCLOSESDIP-SWITCH #2CLOSEDNOYESTHERMOSTATCONTROLELECTRICHEATOUTSIDE AIRDAMPER AT MINIMU

DIP-SWITCH #8CLOSEDNOYESCOOLING UNIT WITHOR WITHOUT HEATHEAT PUMPOPERATION, DIPSWITCH #7 ISIGNOREDSPACE SENSORCONTROL,CLOSE DIP-SWITCHTHERMOSTATCLOSES

Cooling Control (CCN and Remote Start/StopOnly)COOLING CONTROL MASTER LOOP —The cooling con-trol master loop is used to calculate the desired supply-a

POWER UP STARTSYESNONOYESYESDIP-SWITCH #6TOGGLEDCOMPRESSOR 1COMPLETES A MAXIMUM30 SECOND DELAY FROMDIP-SWITCH TOGGLECOMPRESSOR 1COMPLETES5 MIN. TIME