Carrier PC 111 Operating And Troubleshooting Manual

Also see for 48FK034: Controls operation and troubleshooting

25MODULATING POWER EXHAUST48FK,JK and 50FK, JK Units — The tubing for the buildingpressure control (achieved via the Modulating Power Exhaustoption/accessory) should sample building pressure in the areanear the entrance lobby (or other appropriate and sensitivelocation) so that location is controlled as closely to design pres-sures as possible.A differential pressure switch (DPS) is used to control theactuator on the modulating discharge damper in exhaust fanno. 1. The building pressure (BP) DPS is located in the auxilia-ry control box of the unit. See Fig. 33 and 35. Use a nominal3/8-in. plastic tubing.For instructions on adjusting BP control set points, refer toStart-Up, Modulating Power Exhaust section in this book.48FM and 50FM,FS Units — The tubing for the buildingpressure control (achieved through the High Capacity Modu-lating Power Exhaust) should sample the building pressure inthe area near the entrance lobby (or other appropriate and sen-sitive location) so that the location is controlled as closely todesign pressures as possible.A building pressure transducer (BPT) is used to sense thebuilding pressure and supply a 4 to 20 mA signal to the powerexhaust VFD (PE VFD) which controls the speed of exhaustfan motor no. 1 and stages on/off power exhaust fan motorno. 2 to maintain the building pressure. The BPT is located inthe auxiliary control box. Use a nominal 1/4-in. plastic tubing.For instructions on adjusting the BP control set point, referto Start-Up, High Capacity Modulating Power Exhaust sectionin this book.START-UPInitial Check1. Verify unit has been installed per the Installation Instruc-tions included in the unit installation packet.2. Verify that all auxiliary components (sensors, controls,etc.) have been installed and wired to the unit controlboxes per these instructions, the unit Installation Instruc-tions, and the unit wiring label diagrams.3. Verify that air pressure hoses (static, duct, etc.) are prop-erly attached, routed, and free from pinches or crimps thatmay affect proper control operation.4. Set any control configurations that are required (field-installed accessories, etc.). The unit is factory configuredfor all appropriate factory-installed options with the ap-plicable controls programmed to the default values.5. Check and adjust unit set points. See Table 9.6. Check tightness of all electrical connections.7. Perform quick test (see Quick Test Program section onpage 31).IMPORTANT: Do not attempt to start unit, evenmomentarily, until all items on the Controls Start-UpChecklist (in installation instructions) and the followingsteps have been completed.Fig. 33 — Modulating Power Exhaust and InletGuide Vane Differential Pressure Switch(Sizes 034-048)Fig. 34 — Inlet Guide Vane DifferentialPressure Switch and Variable Frequency Drive(Sizes 054-104)Fig. 35 — Modulating Power Exhaust DifferentialPressure Switch (Sizes 054-104)