York SUNLINE MAGNADRY WR240 Technical Manual

Also see for SUNLINE MAGNADRY WR 180: Technical guide Installation manual

Contents

York SUNLINE MAGNADRY WR240 Technical Manual Manual pdf 5 page image

262292-YTG-B-0107Unitary Products Group 5• Electric Heat Operation - All electric heat models(factory installed only) are wired for a single power sourceand include a bank of nickel chromium elements mountedat the discharge of the supply air blower to provide a highvelocity and uniform distribution of air across the heatingelements. Every element is fully protected againstexcessive current and temperature by fuses and twothermal limit switches.• The power supply wiring can be routed into the controlbox through a threaded pipe connection in the base pan ofthe unit or through a knockout in the wiring panel on thefront of the unit.• BAS Controls - York’s Magnum series units offer factorymounted BAS controls such as Novar, Honeywell,Johnson, and CPC.REHEAT MODE SEQUENCE OF OPERATIONThe reheat control board allows the user to select two differentmodes of operation via a jumper connection on the board. (SeeFigure 2.) Each mode is described below. Refer to Figures 2 - 4when reading this section.“NORMAL” MODEWhen the reheat control board (RCB) detects a need fordehumidification (24VAC) at "HUM" via the field supplieddehumidistat connected to RHTB-1 and RHTB-2 and there isnot a call for cooling, it energizes the hot gas relay (HGR),which energizes the 3-way valve (SOL 3), the condenser coilvalve (SOL 2), and de-energizes the reheat coil bleed valve(SOL 1). The Y1 signal is passed to the unit control board(UCB), which engages circuit # 1, resulting in circuit #1 reheatmode operation.When the room thermostat calls for first stage cooling, with orwithout a call for dehumidification, the RCB senses a signalthrough "Y1", de-energizing the HGR, which de-energizes SOL3 and SOL 2, and energizes SOL 1, engaging circuit # 1,resulting in circuit #1 cooling mode operation.When the room thermostat calls for second stage cooling, theRCB senses a signal through "Y1" & "Y2" and engages circuit#1 and circuit #2 in the cooling mode.Indoor blower operation is initiated upon a call for first stagecooling, second stage cooling or dehumidification.FIGURE 1: UNIT CUTAWAYLOCATION OF VFD (Optional)LOCATION OF VFD BYPASS (Optional)