Honeywell THE ST IS A LOW VOLTAGE TIME/ TEMPERATURE DEFROST CONTROLLER FOR HEAT PUMPS. {1 Mounts in outdoor section of heat pump. UJ STAT resets the defrost cycle by remote contact closure. [187748 resets the defrost cycle by on board electronic logic, [ Defrost ON time is 10 minutes. Defrost can be terminated earlier if outdoor coil thermostat is satisfied. [1 Defrost OFF time interval is model dependent. Three field delectable timings per model.
SPECIFICATIONS IMPORTANT THE SPECIFICATIONS GIVEN [N THIS PUBLICATION DO NOT INCLUDE NORMAL MANUFACTURING TOLERANCES. THEREFORE, THIS UNIT MAY NOT MATCH THE LISTED SPECIFICATIONS EXACTLY. ALSO, THIS PRODUCT IS TESTED AND CALIBRATED UNDER CLOSELY CONTROLLED CONDITIONS, AND SOME MINOR DIFFERENCES IN PERFORMANCE CAN BE EXPECTED IF THOSE CONDITIONS ARE CHANGED. MODELS: STAT Defrost Controller with remote reset. STUB Defrost Controller with on-board reset TERMINAL CONNECTIONS: 1/4 in. male quick-connects.
(ye pea 1.21 ve great] MOUNTING Mount the ST in the wiring compartment in the outdoor section of the heat pump, using sheet metal screws in the four mounting eyelets. The control may be mounted in any position, +45 degrees to vertical. WIRING Alb wiring must comply with cola! codes and ordinances. Refer to Fig. 2 or 3 for wiring hookup. The OFF cycle time is determined by a electable Jumper allowing a choice minutes respectively. Also available are and 50, 80, or 110 minute models.
GRINGO VIAL. THERMOSTAT FORES TAT vee DEFROST RELAY WOD NO A¥E GTH L5H A CONNECT JUMPER LEAD FOR DESIRED GFF TIE AS FOLLOWS (MINUTES “= GN STANDARD MOTEL): 71 =50, IGNITIONS ON THEE MODELS: 52,30, 11. O FIG. 3--STUB WIRING HOOKUP. TYPICAL OPERATION OF ST 1. POWER UP Wall thermostat closed With 24 Vac applied, the OFF cycle timing will be started. 2.
OFF CYCLE TIMING MODE {DELECTABLE TIME) ON CYCLE TIMING MODE | DEFROST 10 MIN. INITIATED SETS ALL TIMERS TO ZERO coi. NO THERMOSTAT CLOSED PULLS Ww DEFROST BELAY i oor | OFF CYCLE incitement | HOLD MODE rr molar SS ous ON CYCLE THERMOSTAT nonviolence ven | HOLD MODE ACCUMULATES ON CYCLE TIME ON CYCLE COMPLETE YES DEFROST TERMINATED zoster FIG. 4—TYPICAL OPERATION SEQUENCE OF STAT TIME/ TEMPERATURE DEFROST CONTROL.
¥ | _SETS ALL TIMERS TO ZERO OFF CYCLE TIMING MODE (DELECTABLE TIME) woos ore | OFF CYCLE Cree never | HOLD MODE i ax THERMOSTAT corer con Tomatoes ww hse [I rer ACCUMULATES YES ! ON CYCLE TIME ON CYCLE TIME T ON CYCLE TIMING MODE on corer 10 MIN. Defrost Cow pens wall THERMOSTAT OPEN Ho 3 DROPS OUT BROS OUT ed DEFROST. DEFROST DEFROST RELAY RELAY TERMINATED By FIG. 5—TYPICAL OPERATION SEQUENCE OF STUB TIME/TEMPERATURE DEFROST CONTROL. Honeywell Inc.