York PREDATOR MagnaDRY DR090 Technical Manual

Also see for PREDATOR MagnaDRY DR090: Installation manual Installation manual

Contents

246721-YTG-C-060610 Unitary Products GroupWhen the room thermostat calls for second stage cooling, theRCB senses a signal through "Y1" & "Y2" and engages circuit#1 and circuit #2 in cooling mode.Indoor blower operation is initiated upon a call for first stagecooling, second stage cooling or dehumidification.Anytime there is a call for 2 stages of cooling, the unit will notoperate in the reheat mode, even if there is a call for dehu-midification at "HUM".The unit will not operate in the reheat mode if there is any callfor heating.On units with economizers, the unit will not operate in thereheat mode if there is a call for cooling and the economizeris operating as first stage of cooling.All safety devices function as previously described."ALTERNATE” MODEWhen the RCB detects a need for dehumidification (24VAC)at "HUM" via the field supplied dehumidistat connected toRHTB-1 and RHTB-2, and there is not a call for cooling, itenergizes the HGR, which energizes the SOL 3, SOL 2, andde-energizes SOL 1. (In the DR150, SOL 2 is only energizedwhen the discharge pressure in circuit #1 rises above 235psig and de-energizes SOL 2 after the discharge pressurefalls below 175 psig. Both outdoor fans of circuit #1 in theDR150 also disengage to conserve energy.) The unit thenoperates with circuit #1 in reheat mode and circuit #2 in cool-ing mode.When the room thermostat calls for first stage cooling whilethere is still a call for dehumidification, no operational changeis made. The call for cooling is ignored and the unit continuesto operate with circuit #1 in reheat mode and circuit #2 incooling mode.When the room thermostat calls for second stage cooling, theRCB senses a signal through "Y1" and "Y2" and de-ener-gizes the HGR, which de-energizes SOL 3 and SOL 2, andenergizes SOL 1. Both circuits operate in the cooling mode.Indoor blower operation is initiated upon a call for first stagecooling, second stage cooling or dehumidification.Anytime there is a call for 2 stages of cooling, the unit will notoperate in the reheat mode, even if there is still a call fordehumidification at "HUM".The unit will not operate in the reheat mode if there is any callfor heating.All safety devices function as previously described.FIGURE 3 - REHEAT CONTROL BOARDRY1Y2GW1OCCCW2P4P5P6 P3COMHGRRHGR HUMK1K2K4K3`MODESELECTIONJUMPERDEHUMIDISTATHARNESSCONNECTION