Carrier 48LC 04 Controls, Start-up, Operation And Troubleshooting

Also see for 48LC 05: Controls, Start-Up, Operation and Troubleshooting Service and maintenance instructions Service and maintenance instructions

Carrier 48LC 04 Controls, Start-up, Operation And Troubleshooting Manual pdf 8 page image

8Gas Heat (48LC)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 were changedout for elevation or Liquid Propane purposes, verify properinstallation. Visually inspect other components in heat section.Verify gas pressures before turning on heat as follows:1. Turn off field-supplied manual gas stop, located external tounit.2. Connect pressure gauge to supply gas tap, located onfield-supplied manual shutoff valve. (See Fig. 5.)MANUAL SHUT OFF(FIELD SUPPLIED)PRESSURE TAP(1/8˝ NPT PLUG)GASSUPPLYSEDIMENT TRAPUNIONTOUNITC09242Fig. 5 -- 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 (first stageof heat) using the Scrolling Marquee.5. After the unit has run for several minutes, verify the supplygas pressure is adequate per the base unit installation in-structions. 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 spacetemperature 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.CONTROLS QUICK SET--UPThe following information will provide a quick guide to setting upand configuring the 48/50LC series units with ComfortLinkcontrols. Unit controls are pre-configured at the factory forfactory-installed options. Field-installed accessories will requireconfiguration at start-up. Service Test is recommended for initialstart--up. Additionally, specific job requirements may requirechanges to default configuration values. See the CCN and Displayparameter tables and other sections of these instructions for moredetails. Refer to the Major System Components or accessoryinstallation instructions for specific wiring detail.Control Set Point and Configuration LogDuring start up, accessory installation, and equipment service setpoints and/or configuration changes might have to be made. Whensetting set points or changing configuration settings,documentation is recommend. The Control Log starting on page80. should be filled out and left with the unit at all times, a copyshould also be provided to the equipment owner.Thermostat ControlWire accessory thermostat to the corresponding R, Y1, Y2, W1,W2, and G terminals on the field connection terminal board locatedat the unit control box.The Unit Control Type configuration, ConfigurationUNITU.CTL, default value is for Thermostat (2) so there isno need to configure this item.The Thermostat Control Type, Configuration UNITT.CTL,selects the unit response to the thermostat inputs above.NOTE: May not be compatible with heat anticipator thermostats.Space Temperature Sensor Control -- Direct Wired(T--55 or T--56 or T--59)Wire accessory space temperature sensor(s) to the T-55 terminalson the field connection terminal board located at the unit controlbox. Refer to Field-Installed Accessories section for additionalinformation.The Unit Control Type configuration, ConfigurationUNITU.CTL, must be set to Space Sensor (3). The jumperwire in the installer’s packet must be connected between R and W1on TB for heating mode to operate.T--58 Communicating Room SensorInstall the T-58 communicating thermostat. Connect the CCNcommunication bus from the T-58 to the CCN terminals on thefield connection terminal board located at the unit control box.Configure the unit’s CCN communication element number, busnumber, and baud rate. Configure the T--58’s CCN communicationbus number and baud rate the same as the unit, while the elementnumber has to be different. Configure the T--58 to send SPT to theunit’s element number. Refer to the Field--Installed Accessoriessection for additional information.The Unit Control Type configuration, ConfigurationUNITU.CTL, must be set to Space Sensor (3). The jumperwire in the installer’s packet must be connected between R and W1on TB for heating mode to operate.CCN Linkage ControlThe CCN communication must be properly configured for the48/50LC units and all other devices. Linkage configuration isautomatically done by the supervisory CCN Linkage device.The Unit Control Type configuration, ConfigurationUNITU.CTL must be set to Space Sensor (3). The jumperwire in the installer’s packet must be connected between R and W1on TB for heating mode to operate.Installation of an accessory supply air temperature (SAT) sensor inthe supply duct is recommended for Linkage applications. Asupply duct SAT measurement is valid for heating mode display,while the factory-standard internal SAT is not valid for heating dueto its location upstream of the heating section. When installing thesupply duct SAT, the heating mode display is enabled by settingConfigurationHEATSAT.H to ENBL.Installation of an accessory return air temperature (RAT) sensor inthe return duct and wired to the space sensor input is recommendedfor Linkage applications. This will allow the unit to continue torun if Linkage communication is lost.System Pilott -- Communication Space SensorInstall the System Pilot and connect the CCN communication busfrom it to the unit’s CCN connection on the low voltage terminalboard. Configure the unit’s CCN communication element number,bus number, and baud rate. Refer to the System Pilot’s installationinstructions for configuring it to be used as a space temperature andattaching it to a unit.Thermidistat ControlThe thermidistat is a thermostat and humidistat combinedand the inputs are provided on the field connection terminal board. Theunit control type configuration, ConfigurationUNITU.CTL,default value is for thermostat (2) so there is no need to configure this48/50LC