valutazioni - 3, GPA: 4 ( )

Produttore : Carrier File Size : 1.22 mb File Nome : Lingua di insegnamento:

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 values of the manufacturer. Refer to the Carrier literature when checking default values. The following default values have been changed from the manufacturer settings to more closely match the VFD operation to a Carrier VAV unit. SETUP PARAMETERS (Item 6, Point 1, Output Fre quency) — The default value should be 20. JUMP FREQUENCY GROUP (Item 7, PID Set Point Control Select) — The default value is 1. JUMP FREQUENCY GROUP (Item 8, Proportional Gain) — The default value is 100. JUMP FREQUENCY GROUP (Item 9, Integral Gain) — The default value is 50. SPEED GROUP PARAMETERS (Item 2, Multi-Speed Run Frequency No. 1) — The factory setting is 30. SPEED GROUP PARAMETERS (Item 2, Fire Speed Override Frequency) — 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 field 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 — 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 modified, 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 sequencer system. This system consists of a model R353 signal input module and 4 model S353 staging modules. The signal input module receivesa0to10vdc signal from the building pressure transducer, which is mounted adjacent to the supply static transducer behind the filter 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 bya0to10vdc signal. A factory- installed hose at the ‘‘Lo’’ connection leads to atmosphere, and a field-supplied hose must be connected to the ‘‘Hi’’ connection 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 staging modules are activated in sequence as the input signal increases. Table 7 — VFD Supply Air Pressure Set Point PRESSURE (in. wg) CONTROL (mA) VFD 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 — Variable Frequency Drive + – DPDP JUMPERSNOTE:TerminalstripislocatedinsidetheVFDatthebottom. (SS2) (SS3) FLA FLB FLC P24 RCH LOW FM AM PP RR IV CC ST F R CC SS1 JOG AD2 RST CC Fig. 41 — VFD Factory-Installed Jumpers 32 At the upper right corner of the board is a set of 5 pins and jumper, which determines the time constant for the control. The time constant is the delay in response built into the controls. The jumper should be on the middle or bottom two pins, for the maximum time constant. The delay can be decreased, if desired, by moving the jumper progressively upward, always jumpering adjacent pins. At the lower left corner of the board below the terminal strip is a resistor marked R27. This must be removed in order to obtain the 0 to 10 vdc signal output. There will not be a resistor on a factory-supplied module, but a resistor may be present on a replacement module and must b...

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