Carrier 48EJ, EW, EK, EY024-048 VFD Supply Air Pressure Set Point, Pressure Control VFD, SET Point

Page 32

To set the VFD, the VFD must be powered up; however, since it is located near the indoor air fan, operation of the fan is not desirable. To disable the fan, perform the follow- ing procedure:

1.Open the indoor fan circuit breaker.

2.Remove the jumper between CC and ST on the terminal strip of the VFD (see Fig. 41).

3.Close the indoor fan circuit breaker. The VFD now is powered but the fan will not operate.

4.On the front of the VFD is a keypad and display which will be used to enter the set point. To access this ®eld, press the ``PRG'' key until the display reads ``S.PrG'' (Speed Group Parameters). Press the arrow key until ``Sr1'' is displayed. This is the VFD set point listed in Table 7.

5.Press the ``READ/WRITE'' key. The set point value will be displayed. Use the up-arrow or down-arrow key to adjust the set point value to the value desired.

6.Press the ``READ/WRITE'' key again to enter the new value.

7.Check the factory default values.

IMPORTANT: The Carrier factory default values for the VFD may be different than the default val- ues of the manufacturer. Refer to the Carrier lit- erature when checking default values. The following default values have been changed from the manu- facturer settings to more closely match the VFD operation to a Carrier VAV unit.

SETUP PARAMETERS (Item 6, Point 1, Output Fre- quency) Ð The default value should be 20.

JUMP FREQUENCY GROUP (Item 7, PID Set Point Control Select) Ð The default value is 1.

JUMP FREQUENCY GROUP (Item 8, Proportional Gain) Ð The default value is 100.

JUMP FREQUENCY GROUP (Item 9, Integral Gain) Ð The default value is 50.

SPEED GROUP PARAMETERS (Item 2, Multi-Speed Run Frequency No. 1) Ð The factory setting is 30.

SPEED GROUP PARAMETERS (Item 2, Fire Speed Override Frequency) Ð The factory setting is 60.

8.Open the indoor fan circuit breaker.

9.Replace the jumper between CC and ST on the terminal strip of the VFD.

10.Close the indoor fan circuit breaker; the VFD now is powered and the fan will operate.

NOTE: Any ®eld measurement of supply fan amps must be taken with an RMS meter between the fan circuit breaker and fan contactor (upstream of VFD).

Power Exhaust Ð The optional non-modulating power exhaust (CV only) is a two-stage design where the operation of the exhaust fans is linked to economizer position. When the supply fan is running and the economizer is 25% open,

the base module closes contacts, activating two exhaust fans. When the economizer position reaches 75% open, the base module activates the other two exhaust fans. The fans will turn off when the economizer closes below the same points. The economizer position set points that trigger the exhaust fans can be modi®ed, but only through use of the Service Tool, Comfort Works, or Building Supervisor software. If single-stage operation is desired, adjust the economizer set points to identical values at the desired point to activate all exhaust fans.

The optional modulating power exhaust (VAV standard, CV optional) is controlled by a modular electronic se- quencer system. This system consists of a model R353 sig- nal input module and 4 model S353 staging modules. The signal input module receives a 0 to 10 vdc signal from the building pressure transducer, which is mounted adjacent to the supply static transducer behind the ®lter access panel. The modules are mounted just below the unit control board. The left module is the R353, and the 4 modules on the right are S353 modules for stages 1 through 4. On the unit wiring label, the R353 is designated PESC, and the S353 modules are designated PES1 through PES4.

The building pressure transducer range is −0.5 to

+0.5 in. wg. It is powered by a 0 to 10 vdc signal. A factory- installed hose at the ``Lo'' connection leads to atmosphere, and a ®eld-supplied hose must be connected to the ``Hi'' con- nection and led into the building to a point where building pressure is to be controlled (positive-pressure building). There is a plug button in the bulkhead just above the transducers, for use in leading the hoses into the building via the return air ductwork.

There are 3 adjustments at the R353 module, all of which have been factory set. In the center of the circuit board is a set of 4 pins with a jumper, labeled J2. This determines the mode of operation. The bottom two pins must be jumpered for direct operation. Direct operation means that the stag- ing modules are activated in sequence as the input signal increases.

Table 7 Ð VFD Supply Air Pressure Set Point

PRESSURE

CONTROL

VFD

(in. wg)

(mA)

SET POINT

0

4.0

0

0.25

4.8

3

0.50

5.6

6

0.75

6.4

9

1.00

7.2

12

1.25

8.0

15

1.50

8.8

18

1.75

9.6

21

2.00

10.4

24

2.25

11.2

27

2.50

12.0

30

2.75

12.8

33

3.00

13.6

36

3.25

14.4

39

3.50

15.2

42

VFD Ð Variable Frequency Drive

FLA FLB FLC P24 RCH LOW FM

AM

PP

RR

IV

CC

ST

F

R

(SS2) (SS3)

CC SS1 JOG AD2 RST CC

+

NOTE: Terminal strip is located inside the VFD at the bottom.

D P D P

JUMPERS

Fig. 41 Ð VFD Factory-Installed Jumpers

32

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Contents Installation, Start-Up Service Instructions Field Fabricate Ductwork Instructions onUnit Leveling Tolerances Dimensions Degrees and InchesRoof Curb Sizes Size WeightUnit Operating Ft-in 48EJ,EKD038 48EJE03848EJ,EKD044 48EJE044Base Unit Dimensions, 48EW,EY024-034 Base Unit Dimensions, 48EW,EY038-048 Unit Weight 48EJ,EK,EW,EYD024 48EJ,EK,EW,EYD028 48EJ,EK,EW,EYD03048EJ,EK,EW,EYD034 48EJ,EK,EW,EYD038Physical Data Unit 48EJ,EK,EW,EY4442/4602 4668/4828 4955/5115 Air Distribution Ð Thru-the-Bottom Combustion Fan Housing Location Unit Configuration Default Cooling Default Heating VAVField Control Remote Start/Stop Make Electrical Connections LED CCNSIO FLA LRA MCA Mocp Electrical DataRLA LRA FLA LRA FLAHacr NECQty 044Heating, Air Conditioning Minimum Circuit AmpsGND Ð Ground Terminal BlockDIP PECCCN Connection Approved Shielded Cables Manufacturer Cable Part no2413 or 8772Make Outdoor-Air Inlet Adjustments Color Code RecommendationsRED WhiteAdding Seal Strip to Top of Hood Sides Adding Foam Strip to Hood Side Mounting Angle With Tabs Attached to Filter Track Assembly Psychrometric Chart for Enthalpy Control Barometric Relief Damper and Power Exhaust Mounting Details Pressure Transducer Locations START-UP SET Point VFD Supply Air Pressure Set PointPressure Control VFD Direct Digital Controls DIP Switch Congura Potentiometer Signal LevelsBuilding Pressure Signal Level VdcDIP Switch Factory Settings Power Exhaust Default Set PointsDIP Switch Conguration Airflow 16,000 17,00018,000 19,000528 572 615 656 695 733 769 805 Fan Performance Ð Power Exhaust Motor LimitationsESP Standard Efficiency MotorsSequence of Operation Air Quantity LimitsUser Dened Set Points GAS HEATING, Variable AIR Volume VAV Units HIR DEG. F ResetCOM Smoke Control Modes Device Pressurization Smoke Purge Evacuation Fire ShutdownCompressor Cooling Capacity Staging Table, CV Units With 2 CompressorsStages Lubrication Manufacturer LubricantEvaporator Fan Service and Replacement Typical Gas Heating SectionEvaporator-Fan Motor Replacement Condenser-Fan AdjustmentBelt Tension Adjustment Protective DevicesGas Valve AHA IFCIfcb TranTypical Power Schematic 48EJ,EK,EW,EY024-034 208/230-3-60 Typical VAV 115-v Control Circuit Typical CV 115-v Control Circuit Typical VAV 24-v Control Circuit Typical CV 24-v Control Circuit Troubleshooting Typical Refrigerant Circuiting 48EJ,EK,EW,EY038,044 Typical Refrigerant Circuiting 48EJ,EK,EW,EY048 IGC Control Heating and Cooling IGC Control Board LED Alarms Control Board LED AlarmsI/O Channel Designations Base Module Ð CV I/O Channel Designations Base Module Ð VAVTerminal no Assignment SPTPackaged Service Training START-UP Checklist General
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EW, EY024-048, EK, 48EJ specifications

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