Carrier 48/50HC04-28 Controls, Start-up, Operation And Troubleshooting

Also see for 50HCQ04---12: Controls, Start-Up, Operation and Troubleshooting Instructions Service and maintenance instructions

Carrier 48/50HC04-28 Controls, Start-up, Operation And Troubleshooting Manual pdf 26 page image

26UNIT OPERATION HAZARDPower must be ON to the RTU Open when replacingthe battery or date, time, and trend data will be lost.CAUTION!1. Remove the battery from the controller, makingnote of the battery’s polarity.2. Insert the new battery, matching the battery’s polaritywith the polarity indicated on the RTU Open .Thermistor TroubleshootingRTU Open uses thermistors to sense temperatures forcontrol operation of the unit. Resistances at varioustemperatures are listed in Table 2. Thermistor pinconnections are shown in Table 1. Thermistors are usedfor supply air temperature (SAT), outdoor air temperature(OAT), and space temperature (SPT) and all must be a 10kilo-ohm type II sensor.To check accuracy, use a high quality digitalvolt-ohmmeter. Connect the meter to the thermistor leadsto obtain a resistance value. Use Table 2 to convert thatresistance to a temperature. Next step is to measuretemperature at probe location with an accuratethermocouple-type temperature-measuring instrument.Temperature measured by thermocouple and temperaturedetermined from thermistor voltage reading should beclose, within 5_F if care was taken in applyingthermocouple and taking readings. If a sensor must becorrected, use the RTU Open’s calibration function tooffset the temperature reading.Software VersionDuring Start-up and throughout the life of the equipment,it may be necessary to obtain the RTU Open’s softwareversion. To do this a module status (Modstat) must be runon the controller. This can be done from Field Assistant orfrom an Equipment Touch. An example of the beginninglines of a Modstat is shown in Fig. 19. The applicationsoftware version shows the current running software of theboard. In this case the rtum2_iv6--3_06_20140403 refersto RTU Open software version 3_06_20140403. The last 8digits of the number refer to a date (YYYYMMDD). Thefirst 4 digits are the year (2014) and the month and day(0403), so this version is April 3, 2014.Table 2 – Thermistor Resistance vs Temperature Valuesfor Space Temperature Sensor, Supply Air TemperatureSensor, and Outdoor Air Temperature SensorTEMP(C)TEMP(F)RESISTANCE(Ohms)---40 ---40 335,651---35 ---31 242,195---30 ---22 176,683---25 ---13 130,243---20 ---4 96,974---15 5 72,895---10 14 55,298---5 23 42,3150 32 32,6515 41 25,39510 50 19,90315 59 15,71420 68 12,49425 77 10,00030 86 8,05635 95 6,53040 104 5,32545 113 4,36750 122 3,60155 131 2,98560 140 2,48765 149 2,08270 158 1,752Communication LED’sThe LED’s indicate if the controller is speaking to thedevices on the network. The LED’s should reflectcommunication traffic based on the baud rate set. Thehigher the baud rate the more solid the LED’s will appear.See Table 3.04/11/2014 12:52:11 CM: 1Device Instance: 1610551Application Software Version: PRG:rtum2_iv6-3_06_20140403Flash Archive Status: Valid on 04/11/14 12:51:121 PRGs loaded. 1 PRGs running.Module status:Firmware sections validated in flash memory----------------------------------------------------------------------------------------Boot16-H_IAR - v2.10:001 Apr 18 2013RTU-OPEH DRIVER - v6.00:082 Aug 29 2013C14144Fig. 19 -- Example Modstat48 ---50LHTCQ ---01T