Carrier 48HC 04-28 Controls, Start-up, Operation And Troubleshooting

Also see for /50HC 04-28: Manual

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Carrier 48HC 04-28 Controls, Start-up, Operation And Troubleshooting Manual pdf 10 page image

10Gas Heat (48HC)Inspect the gas heat section of the unit. Verify the number ofburners match the number of heat exchanger openings and theburner assembly is properly aligned. If the orifices werechanged out for elevation or Liquid Propane purposes, verifyproper installation. Visually inspect other components in heatsection.Verify gas pressures before turning on heat as follows:1. Turn off field-supplied manual gas stop, located externalto unit.2. Connect pressure gauge to supply gas tap, located on field-supplied manual shutoff valve. (See Fig. 6.)Fig. 6 — Field Gas Piping3. Connect pressure gauge to manifold pressure tap.4. Turn on field-supplied manual gas stop. Enter Service Testmode by setting Service TestTEST to “ON” using thescrolling marquee display. Temporarily install the jumperwire between “R” and “W1” on TB. Use the Service Testfeature to set Service TestHEATHT.1 to ON (firststage of heat) using the scrolling marquee.5. After the unit has run for several minutes, verify the sup-ply gas pressure is adequate per the base unit installationinstructions. If not, adjust accordingly.NOTE: Supply gas pressure must not exceed 13.0-in. wg.6. Set Service TestHEATHT.1 to OFF using scrollingmarquee.7. Remove jumper wire if the unit will be operating underthermostat mode. The jumper must remain if a space tem-perature sensor (T-55, T-56, T-58, or System Pilot device)will control the unit.8. Exit Service Test mode by setting Service TestTEST to“OFF” using the scrolling marquee.Units with EnergyX ® SystemBASE UNIT EVAPORATOR FANFirst follow the base unit instructions to balance the RTU in-door fan. The ERV (Energy Recovery Ventilator) fans shouldbe off during base unit fan set-up. Before start-up and testingthe ERV, verify that the ComfortLink controller minimumdamper positions are set to 0 and if not change them to 0. Con-figuration →AIR.Q →AQ.MN = 0, and Configuration→ECON →MP.MX = 0. The ERV communicates with theComfortLink controller therefore the scrolling marquee can beused for test mode and configuration of the ERV. The follow-ing sections explain ERV testing and configuration. It is im-portant that these configurations are set correctly in order forthe ERV module to properly control the air performance. Final-ly, with service test disabled run unit under normal operation,verify proper supply airflow with ERV and indoor fan running.START-UP CHECK LISTUse the EnergyX Unit Start-Up Checklist (see page CL-1) inconjunction with the base unit Start-Up checklist from the baseControls book. Fill in all blank data entries that are applicableto the exact unit being installed. The ERV model and serialnumbers are printed in the ERV control box. Save the checklistfor future service and maintenance use. It is recommended thata copy of the checklist be left with the unit in the literature sloton the base unit control box access door.ERV TEST MODEERV Test points should be used when starting up an EnergyXunit to verify proper ERV component operation. It can also beused for troubleshooting. To test the ERV, use the scrollingmarquee to put the ComfortLink RTU into test mode. Then goto Test Independent outputs (Service Test →INDP). Table 3shows a list of test points that can be tested as independent out-puts. There are five ERV tests which can be performed sepa-rately or together while in test mode. Use the scrolling mar-quee to change the value of the test point. Follow the Com-fortLink Controls, Start-Up, Operation, and Troubleshootingmanual for testing the base rooftop unit.The 5 ERV specific test points are OAU 2-position Damper,OAU Wheel Test, OAU OA Fan Speed test, OAU PE FanSpeed Test and OAU Tempering Heater Test. The 2-positiondamper can be opened and closed with the OA.DM point. The2-position damper accessory can be installed on the exhaustopening of the ERV. The ERV wheel motor can be turned onand off with the WHL point. The ERV’s outside air (OA.OF)and building exhaust air (OA.XF) motors can be ramped upand down during test mode their corresponding fan speed testpoints. Table 3 shows the test mode test points in the order theyappear under test mode. Communication failures will not allowthese ERV test points to be changed. The ComfortLink control-ler will show active alarms during test mode.NOTE: If a 2-position damper is installed, it must be opened intest mode while operating the exhaust test.ERV CONFIGURATIONThe ERV configuration menu can be accessed using the Com-fortLink controller scrolling marquee. Enter the Outside AirUnit Configurations (Configuration →OAU) menu. Table 12shows the list of complete outside air unit configurations thatcan be changed and the defaults from the factory. The criticaljob specific configurations are listed below and should bechanged at start up for the specific job site. See the operationsection for details all configurations.OAU Unoccupied Operation (U.RUN)This allows the ERV to run during the unoccupied period whenthe rooftop fan is brought on.MANUAL SHUT OFF(FIELD SUPPLIED)PRESSURE TAP(1/8˝ NPT PLUG)GASSUPPLYSEDIMENT TRAPUNIONTOUNITTable 3 — Service Test Mode Independent TestPointsITEM EXPANSION RANGEINDP Test Independent OutputsECON Economizer Position Test 0 to 100E.CAL Calibrate Economizer Off/OnPE1 Power Exhaust 1 Test Off/OnPE.2 Power Exhaust 2 Test Off/OnALRM Alarm Relay Test Off/OnCCH Crankcase Heat Test Off/OnOA.DM OAU 2-Position Damper Close/OpenWHL OAU Wheel Test 0 to 100OA.OF OAU OA Fan Speed Test 0 to 100OA.XF OUA PE Fan Speed Test 0 to 100OA.HT OAU Tempering Heater Test 0 to 100