Carrier WeatherExpert 48N2 Controls, Start-up, Operation, Service And Troubleshooting Instructions

Also see for WeatherExpert 48N2: Installation instructions Installation instructions Controls, start-up, operation, service, and troubleshooting Installation instructions

Contents

Carrier WeatherExpert 48N2 Controls, Start-up, Operation, Service And Troubleshooting Instructions Manual pdf 33 page image

33• Service TestCOOLRHV (Humidi-MiZer 3-WayValve). On Humidi-MiZer equipped units, this itemallows the user to switch the reheat valve from ON toOFF and vice versa. When RHV is switched to the ONposition, a three-way valve will be energized allowingrefrigerant flow to enter the reheat coil as if in a dehu-midification mode or reheat mode. When RHV isswitched to the OFF position, the three-way valve will bedeenergized and the unit will revert back to normal cool-ing. Note that this function only allows manipulation ofRHV if a compressor on Circuit B has already beenturned ON. To manually exercise this valve without anactive Circuit B compressor, see the section titled Ser-vice TestHMZRRHV. To view the actual valve posi-tion at any time, the user can use the Outputs menu(OutputsCOOLRHV).• Service TestCOOLC.EXV (HMV-1: CondenserEXV Position). On Humidi-MiZer equipped units, thisitem allows the user to exercise the valve that controlsrefrigerant flow to the Circuit B condenser. To exercisethe valve, RHV must first be switched to ON (ServiceTestCOOLRHV) and a Circuit B compressor mustbe commanded ON. The valve default position is 100%(completely open). The user will be able to adjust thevalve from 0 to 100% through this function. The onlyconstraint on the valve position is that the percentagesum of the bypass valve (Service TestCOOLB.EXV) and condenser valve must equal 100%. Forexample, if the condenser modulating valve is only 80%open, then the gas bypass modulating valve must remainat least 20% open. The effect of closing the condenservalve will be to increase the supply-air temperature(additional reheat capacity). To view the actual valveposition at any time, the user can use the Outputs menu(OutputsCOOLC.EXV).• Service TestCOOLB.EXV (HMV-2: Bypass EXVPosition). On Humidi-MiZer equipped units, this itemallows the user to exercise the valve that controls dis-charge gas bypass around the Circuit B condenser. Toexercise the valve, RHV must first be switched to ON(Service TestCOOLRHV) and a Circuit B compres-sor must be commanded ON. The valve default positionis 0% (completely closed). The user will be able to adjustthe valve from 0 to 100% through this function. The onlyconstraint on the valve position is that the percentagesum of the bypass valve and condenser valve (ServiceTestCOOLC.EXV) must equal 100%. For example,if the condenser modulating valve is only 80% open,then the gas bypass modulating valve must remain atleast 20% open. The effect of opening the bypass valvewill be to increase the supply air temperature (additionalreheat capacity). To view the actual valve position at anytime, the user can use the Outputs menu (OutputsCOOLB.EXV).Heating — The Heat Test Mode sub-menu will offer auto-matic fan start-up if not a gas-fired heat unit. On gas heat units,the IGC (integrated gas controller) feedback from the gas con-trol units will bring the fan on as required.Within this sub-menu, control of the following is possible:• Service TestHEATHT.ST (Requested Heat Stage).When this item is non-zero, the currently configured heattype will energize the corresponding heat relay patternthat reflects the requested stage. In addition the upperlimit will be clamped to reflect the maximum configurednumber of stages. When non-zero, the heat relays will be“read-only” and reflect the currently selected pattern.• Service TestHEATHT.1-10, Service TestHEATHIR (Manual Heat Relay Control). If the “HeatStage Request” item is set to zero, it will be possible toindividually control the heat relays, including the heatinterlock relay.• Service TestHEATH1.CP (Modulating Heat Capac-ity). If configured for modulating gas or SCR electricheat, the user will be able to manually control the capac-ity of the modulating heat section (0 to 100%). Therequested heat stage must be greater than or equal to 1 orheat relay 1 must be on before the control will accept amodulating heat capacity request. If neither case is true,the control will overwrite the modulating heat requestback to 0%.• Service TestHEATHTC.C (Ht Coil Command Posi-tion). If configured for hydronic heat type, the user willbe able to manually control the positioning of the actua-tor which controls hot water (0 to 100%).SERVICE COMPONENT TESTSAuto-component testing is the automated testing proceduresof a component or a group of components. Auto-componenttesting can be used during commissioning of a unit to verifythat components are functioning properly. It can also be used asa diagnostics routine for troubleshooting.Control Description (Overview) — The 40/50N Se-ries large rooftop unit is capable of performing auto-compo-nent tests. The auto-component tests appear in Navigator underthe Service Test menu (Service TestAC.DT):The unit must be in Service Test mode to perform the auto-component tests (Service TestTESTON).Starting another test before a currently running test hascompleted will cancel the running test and reset all outputs be-fore starting the newly requested test.Setting Service Test mode to "OFF" while running an auto-component test will cancel the running test and reset all out-puts.For a complete description of notices, alerts and alarms ref-erenced, see the Alarms and Alerts section.Auto-component tests will have a status indicated by thefollowing:1. Not Run2. Running3. Pass4. FailThe results of all auto-component tests will default to "NOTRUN."After power cycling the MBB, the results of all auto-com-ponent tests will default to "NOT RUN."If the required conditions for the test are not met, the testwill not be allowed to run. Note that there may be no indicationfor the possible reasons why a test might not run.For each auto-component test, if the verification criteria ismet, test status will display 'PASS,' if the verification criteria isnot met, test status will display 'FAIL.'CP.TS Compressor Auto-TestDS.TS Dig Scroll Auto-TestEX.TS EXVS Auto-Component TestCD.TS Charge Tst without Lqd Sens.CL.TS Charge Tst with Lqd SensorsML.TS MLV/HGBP Auto-TestSF.TS Supply Fan Auto-TestRSLT Comps Auto-Test Results