Carrier GZ024 Installation Instructions Manual

Carrier GZ024 Installation Instructions Manual Manual pdf 22 page image

22protector closes, (at the next 15 minute interval check) the unitwill resume operation. If the thermal protector trips for threeconsecutive cycles, then unit operation is locked out for 4 hoursand the appropriate fault code is displayed.S NO 230V AT COMPRESSOR CONTACTOR: If thecompressor voltage is not sensed when the compressor should bestarting, the appropriate contactor may be stuck open or there is awiring error. The control will flash the appropriate fault code.Check the contactor and control box wiring. Refer to Table 11and Fig. 24.Table 11 – UPM Voltage DetectionUPM Voltage Detection Fault CodeBrownout L1 and L2 46Compressor voltage sensing VS and L1 74230V line power disconnect detection on L1and L2 47Contactor shorted detection VS and L1 7324V transformer Sec 1 and Sec 2 No faultsFig. 24 -- UPM BoardL1, L2, VS, SEC 1 and SEC 2 LocationsTIMER SPEED--UP (TEST MODE)Timer Speed Up allows the unit to bypass all start timings to below10 seconds to allow the unit to run for testing purposes. This speedup will last one cycle until unit shuts down for the next start.Start timings include:S Anti--short cycle time (5 minutes)S Random startupOn a system with a communicating control, from the main menu,enter the Service mode by holding the Service hat icon forapproximately 10 seconds until it turns green. Enter the checkoutscreen. This allows an option to run 5 minutes low stage or 5minutes high stage, each adjustable up to 120 minutes andstoppable at any time.AUXILIARY HEAT LOCKOUTThe following applies to GZ split units used with a gas furnace orfan coil with electric heat:When using the GZ communicating units, the “Lock--out” featurefor the gas furnace or electric heat is not enabled on theInfinity/Evolution wall control. The wall control is “in charge” ofthe comfort and the staging. Staging is not to be controlled by aone time set--up selection or by a temporary manual override.When the GHP is no longer able to satisfy the thermostat in first orsecond stage heating, operation will automatically switch from theGHP to the gas furnace or electric heat, which will remain inoperation until the thermostat is satisfied. Although somecustomers want control of that changeover point based on a setoutdoor air temperature, this can negatively affect the comfort andperformance of the GHP.S If the changeover temperature would be set too high, then theGHP would not be providing the customer with the bestefficiency due to extended operation (run hours) of the gasfurnace or electric heat resulting in higher energy costs than thecustomer anticipated.S If the changeover temperature would be set too low, then the GHPwould operate in conditions outside its design condition resultingin poor performance. For example, if the GHP and loop are sizedto provide all the heating requirements down to 15_F prior toauxiliary heat (gas furnace or electric heat operation), thenoperating the GHP at outdoor temperatures lower than 15 _Fwould result in continuous run times, reducing the looptemperature lower than its design condition. The lower looptemperature then results in lower capacity for the GHP, causing itto keep running in an attempt to satisfy the thermostat. The loopwill continue to drop in temperature, causing further reduction incapacity and efficiency. This results in a negative “fly wheel”effect that is inescapable unless auxiliary heat is used or theoutdoor temperature increases.S In an open loop/well water application where the changeovertemperature would be set too low and auxiliary heat waslocked--out, the unit would not be able to maintain the heating setpoint and comfort would be compromised.S The wall control takes the guesswork out of determining thechange--over set--point and ensures that comfort and performanceare not compromised.Emerging From Set--BackSome key operational features to consider are below:In set--back (heating) mode:S When coming out of set--back, the system will always first engagethe GHP in first stage heat, then second stage heat, then auxiliaryback--up (electric resistance or furnace).S The system uses intelligent recovery.S Back--up heat is not engaged until it has been determined by thecontrol that second stage heat is not satisfying the thermostat.If the homeowner manually bumps up the heating setpoint severaldegrees:S The system will always first engage the GHP in first stage heat,then second stage heat, then auxiliary back--up (electric resistanceor furnace).S Back--up heat is not engaged until it has been determined by thecontrol that second stage heat is not satisfying the thermostat.S The duration of this attempt varies based on the rate oftemperature rise and the difference in set--point, but is typicallyless than 30 minutes. The reason behind this is that the systemthinks that if the homeowner increases the setpoint from, forexample 70_ to 74_, the extra heat is wanted now.