Carrier Residential Air Conditioners and Heat Pumps Application Manualline

Also see for 24ANB124: Installation instructions

Carrier Residential Air Conditioners and Heat Pumps Application Manualline Manual pdf 44 page image

44TWO--STAGE 25HNB/24ANBApplication GuidelinesCarrier designed and tested the two--stage air conditioner and heatpump products with Puron refrigerant to operate at a minimumoutdoor operating ambient in cooling mode at 55_F without lowambient cooling enabled and the maximum outdoor operatingambient in cooling is 125_F/51.6_C. On Infinity communicatingsystems, only low ambient cooling is available to 0_F/--17.8_C.The maximum outdoor operating ambient in heating mode is66_F/18.8_C on all heat pumps. Continuous operation in heatingmode is approved to --30_F/--34.4_C. Thermostat options for thetwo stage units are as follows:S A,B,C,D four--wire connections for Infinity UserInterface.S R,C,W,Y1,Y2, and O wire connections for standard,non--communicating thermostat.25HNB6, 25HNB9, 24ANB7, and 24ANB1 units can run, and arematched with, User Interface (UI) communicating andnon--communicating indoor fan coils and furnaces. Only unitcombinations listed in the two--stage Product Data arerecommended.Line sets for two stage units are similar to the single stage units.However, some restrictions may apply to specific combinations inlong line applications. Refer to the Long Line Guideline for furtherinformation.The Tennessee Valley Authority (TVA) requires that electric stripheat have a lockout feature. This is achieved through Carrierthermostats required per above and must be used on all TVAapproved units.The new control board in the two stage units with Puron refrigeranthas dip switches for defrost timing. The Infinity controls providethese two stage units with high stage latching and Hybrid Heatt(dual fuel) capabilities. The standard Hybrid Heatt (duel fuel)thermostat can be used on two stage units with Bristolreciprocating compressors only.Model PlugEach control board contains a model plug. The correct model plugmust be installed in order for the system to operate properly. (SeeTable 13.)The model plug is used to identify the type and size of unit to thecontrol. On 25HNB6 models, the model plug is also used todetermine the start sequence timing for each individual model.On new units, the model and serial numbers are inputted into theboard’s memory at the factory. If a model plug is lost or missing atinitial installation, the unit will operate according to theinformation input at the factory and the appropriate error code willflash temporarily. An RCD replacement board contains no modeland serial information. If the factory control board fails, the modelplug must be transferred from the original board to the replacementboard for the unit to operate.NOTE: The model plug takes priority over factory modelinformation input at the factory. If the model plug is removed afterinitial power up, the unit will operate according to the last validmodel plug installed, and flash the appropriate fault codetemporarily.Table 13—Model Plug InformationMODELNUMBERMODELPLUGNUMBERPIN RESISTANCE(K---ohms)Pins 1---4 Pins 2---325HNB624 HK70EZ041 18 9125HNB636 HK70EZ043 18 15025HNB648 HK70EZ045 18 22025HNB660 HK70EZ047 18 36025HN9624 HK70EZ010 5.1 12025HNB936 HK70EZ012 5.1 18025HNB948 HK70EZ014 5.1 27025HNB960 HK70EZ016 11 5.124ANB124 HK70EZ009 5.1 9124ANB136 HK70EZ011 5.1 15024ANB148 HK70EZ013 5.1 22024ANB160 HK70EZ015 5.1 36024ANB724 HK70EZ040 18 7524ANB736 HK70EZ042 18 12024ANB748 HK70EZ044 18 18024ANB760 HK70EZ046 18 270