Carrier PC 111 Operating And Troubleshooting Manual

Also see for 48FK034: Controls operation and troubleshooting

27DIP SWITCH NO. 1 — Supply Air Set Point (SASP) ResetType. Factory setting is OFF. Do not change.DIP SWITCH NO. 2 — SASP Reset Enabled. Factory settingis OFF (no SASP reset enabled). If SASP reset has beeninstalled, enable it by changing switch position to ON.DIP SWITCH NO. 3 — Economizer option. If economizeroption has been installed, this switch will be ON. If there is noeconomizer installed, this switch will be OFF. For all 48FMand 50FM,FS units, this switch will be ON. Confirm settingper Table 10. Change only if in error.DIP SWITCH NO. 4 — Morning Warm-Up. For 48FK,FM,JKunits, this switch will be ON (morning warm-up enabled). For50FK,JK units with factory-installed electric heaters, thisswitch will be ON. For all other units, this switch will be OFF.If accessory electric heaters are installed (for 50FK,JK 034-074 units without plenum option), change this switch to ON.DIP SWITCH NO. 5 — Demand Limit. Factory setting is OFF(demand limit not enabled). If Demand Limit (single-step or2-step accessory) has been installed, change this switch to ON.DIP SWITCHES NO. 6 AND NO. 7 — Unloader Configu-ration. These are factory set to match unit size. Confirm set-tings per Table 12. Change only if in error.Table 12 — DIP SwitchesLEGEND*Control circuit breaker must be off before changing the setting of the DIPswitch.†No economizer.**And/or electric heat (50FK,JK034-074 units without plenum only).Adjusting Set Points — Set points for unit operationare established via potentiometer settings. Set points for SupplyFan controls are set at the VFD keypad (if installed) or at theIGV differential pressure switch (DPS1) (if IGV option in-stalled). Set points for modulating power exhaust (option or ac-cessory) are set at the differential pressure switch (DPS2).Set points for high capacity modulating power exhaust(48FM and 50FM,FS units) are set at the power exhaust VFDkeypad.Potentiometers — All of the set point potentiometersmust be set before the unit is started in order for the unit tofunction properly. Each of the potentiometers has a valid rangethat is used by the control. The valid range is defined as the po-tentiometer’s resistance value that the control will not considerto be in error. This is usually between 10% and 90% of the po-tentiometer’s total resistance. The control has been pro-grammed to accept an operational range for the potentiometer,which may not be the same as the valid range.Potentiometer inputs and ranges are summarized in Table 9.Information on individual set point potentiometers (includingfunction, location and range data) are shown below:SUPPLY AIR SET POINT (Leaving-Air Temperature) (P1)— This potentiometer establishes the set point for coolingcycle operation of the VAV unit. The VAV control uses a validcontrol range of 45 to 70 F, and the potentiometer has a validrange of –22 to 70 F. If the set point is between –22 and 45 F,the control will use a value of 45 F. If the set point is outsidethe valid range (less than –22 F or greater than 70 F), an alarmcondition will be signaled and a default value of 70 F will beused.ECONOMIZER MINIMUM POSITION (P5) — This potenti-ometer specifies the minimum opening position for theoptional economizer during running periods. It has both a validrange and an operational range of 0 to 100%.SASP RESET TEMPERATURE (P7) — This potentiometerestablishes the space temperature at which the control will ini-tiate the reset of the SASP (i.e., the unit control begins to raisethe base SASP, to prevent overcooling of the space). Thepotentiometer has a valid range of 40 to 100 F. Refer to SpaceTemperature Reset section on page 13 for further discussion ofSASP Reset operation.RESET LIMIT (P3) — Used in conjunction with P7 potenti-ometer, this potentiometer establishes the maximum tempera-ture for the modified SASP value during the Reset function.This potentiometer has a valid range of 0° to 80 F.DEMAND LIMIT, SINGLE-STEP (P4) — This potentiome-ter establishes the maximum amount of compressor capacitypermitted by the unit control when single-step demand limitoperation is implemented (by closing contact set to potentiom-eter wiper arm). This potentiometer is field-supplied and-installed and will be located in the main control box. Thevalid range is 0% to 100%, which is also the operational range.If the wiper arm is open, all capacity stages can be used.When the wiper arm is closed, the capacity is reduced by theamount set on potentiometer P4.DEMAND LIMIT, 2-STEP — The accessory 2-step demandlimit control is a 2-potentiometer system. The demand limitcontrol board (DLCM) accessory board is field-installed in themain control box; the 2 control potentiometers are located onthe DLCM. Potentiometer DLCM-P1 establishes the maxi-mum amount of compressor capacity available when SW1 isclosed and has a valid range is 50% to 100%. PotentiometerDLCM-P2 establishes the maximum amount of compressorcapacity available when SW2 is closed and has a valid range is0% to 49%.If no power is supplied to the DLCM, all capacity stagescan be used. When power is supplied to terminal IN1 only, thefirst step of demand limit control is energized and the capacityis reduced by the amount set on potentiometer P1. When poweris supplied to IN2 (or IN1 and IN2), the capacity is reduced bythe amount set on potentiometer P2.MORNING WARM-UP (P6) — This potentiometer estab-lishes the set point temperature for the Morning Warm-Upfunction. This is the temperature at which the morning warm-up sequence is terminated and VAV cooling operation begins.The valid control range is 0° to 95 F, but the control is pro-grammed to accept a range of 40 to 80 F. If the set point isbetween 0° and 40 F, the control will use a value of 40 F. If theset point is between 80 and 95 F, the control will use a value of80 F. If the set point is outside the valid range (less than 0° F orgreater than 95 F, an alarm condition will be signaled and adefault value of 40 F will be used.SWITCHNO. FUNCTION SWITCHPOSITION* MEANING1 ResetMode Off Space or Outdoor-Air Reset(DO NOT CHANGE)2 ResetSelect OnOff Reset UsedReset Not Used3 Economizer OnOff Enable EconomizerDisable Economizer†4 MorningWarm-UpOnOffEnable Morning Warm-Up**Disable Morning Warm-Up**5 DemandLimit OnOff Enable Demand LimitDisable Demand Limit6,7 Unloaders Off, OffOn, OffOff, OnNo Unloaders1 Unloader2 Unloaders8 Not Used Off No SignificanceDIP — Dual, In-Line Package