Download Honeywell ST9141A1002 User's Manual
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ST9141A1002 Electronic Fan Timer Application The ST9141A1002 Electronic Fan Timer integrates control of all combustion blower and circulating fan operations in a gas warm air appliance. This control is the central wiring point for most of the electrical components in the furnace. The basic purposes of the ST9141A1002 are to monitor the thermostat for heat, cool, and fan demands and run the induced draft blower motor and up to a two-speed circulating fan as required. The ST9141A1002 monitors an spdt pressure switch, burner limit and primary limit. A Honeywell SV9500 Hot Surface Pilot Ignition System Control manages the burner, which is energized through the pressure switch. A light-emitting diode (LED) indicates system status. In addition, this model includes electronic air cleaner and humidifier convenience terminal connections. LIGHT-EMITTING DIODE (LED) INDICATIONS: LED flashing dim-bright indicates normal operation. LED off when control is powered indicates defective control. LED on continuously when control is powered indicates defective control. LED flashing in a cycle with LED on followed by one or more off pulses indicates the following system errors. Number of Off Flash Pulses 1 2 3 NOTE: Use this control to replace an identical ST9141A1002 Electronic Fan Timer only. This control is not for use in general applications. 4 System Condition Burner limit circuit is open. Primary limit circuit is open. Pressure switch circuit is improperly closed. Control is in lockout due to air not circulating (overheating). Specifications ELECTRICAL RATINGS: Power Requirements: Voltage: 18-30 Vac, 60 Hz. Contact Ratings: Combustion Blower: 1.5A Full Load, 10A Locked Rotor at 115 Vac. .75A Full Load, 5A Locked Rotor at 230 Vac. Reduce full load rating by humidifier load. Circulating Fan (Heat-Cool Speed): 15A Full Load, 30A Locked Rotor at 115 Vac. 7.5A Full Load, 15A Locked Rotor at 230 Vac. Reduce full load rating by electronic air cleaner load. Thermostat Load: 0.06A plus ignition system current draw. ON/OFF DELAY SETTINGS: Heat Speed: Delay On: 30 seconds, fixed. Delay Off: 60, 100, 140 or 180 seconds, field adjustable. Cool Speed: Delay On: 6 seconds, fixed. Delay Off: 60 seconds, fixed. Timing Tolerance: Larger of ±5% or ±2 seconds. POSTPURGE TIMING: 5 seconds. ENVIRONMENTAL RATINGS Temperature: -40° to +175° F [-40° to +79° C]. Humidity: 5 to 95%, noncondensing. Installation WHEN INSTALLING THIS PRODUCT… 1. Read these instructions carefully. Failure to follow them could damage the product or cause a hazardous condition. 2. Check the ratings and specifications given in the instructions and on the product to ensure the product is suitable for your application. 3. Installer must be a trained, experienced service technician. 4. After installation is complete, check out the product operation as provided in these instructions. ! CAUTION Disconnect power supply before wiring to prevent electrical shock or equipment damage. Location and Mounting The ST9141A1002 is mounted in the appliance wiring compartment using four No. 6 screws (obtained locally) through holes on the corners of the enclosure. Wiring All wiring must comply with local codes and ordinances. Disconnect power before making wiring connections. Refer to Fig. 1 for standard wiring connections. Refer to Fig. 2 for an internal schematic. C.H. 1• 6-93 • ©Honeywell Inc. 1993 • Form Number 69-0780 69-0780 Fig. 1—Typical ST9141A1002 wiring connections. HUMIDIFIER L1 (H) FUSE L2 (N) AIR CLEANER TO 120 VAC POWER SUPPLY 120 VAC TRANSFORMER 24 VAC COMBUSTION BLOWER 2 3 C NEUTRAL N CIR STARTING CAP SV9500 HOT SURFACE PILOT IGNITION SYSTEM CONTROL SEC X X BLWR HEAT N BURNER LIMIT 4 XFMR 1 N CONT COOL EAC LEADS DI HUM 2 MOTOR 3 1 UNUSED PRIMARY LIMIT LO ML MH HI N.C. Z1 N.O. ST9141 CIRCULATING FAN Z2 PRESSURE SWITCH THERMOSTAT DELAY 1 W Y G R 2 OFF COOLING CONTACTOR SPEED UP C Y C G Y W R 24 VOLT COMMON 24 VOLT HOT EFT OUTPUT NOTE: 24 VOLT THERMOSTAT OR PRESSURE SWITCH = DENOTES STANDARD TERMINAL. = DENOTES TERMINAL NOT PROVIDED. DENOTES LINE VOLTAGE CONNECTIONS. DENOTES LOW VOLTAGE CONNECTIONS. 2 M5607 Fig. 2—ST9141A1002 internal schematic. L1 (H) FUSE L2 (N) TO 120 VAC POWER SUPPLY INTERLOCK L1-1 N1 EAC (N) EAC (S) ELECTRONIC AIR CLEANER LOW M2 CIRCULATING FAN MED-LOW K1 K2 HEAT K2 COOL MED-HIGH M1 N2 HIGH HUM (S) HUM (N) HUMIDIFIER K3A COMBUSTION AIR BLOWER DI N3 N4 L1-2 120 VAC TRANSFORMER CN1 X 1 C 24 VAC X-OT BURNER LIMIT 6 PRIMARY LIMIT ST9141A ELECTRONIC FAN TIMER 8 THERMOSTAT C R-OT G PS1 Y 3 N.C. N.O. W K3B R COM. 7 PS2 FT PRESSURE SWITCH 24V C 4 2 COOLING CONTACTOR 5 24V NOTE: DOTTED LINES REPRESENT PRINTED CIRCUIT BOARD WIRING. 3 SV9500 HOT SURFACE PILOT IGNITION SYSTEM CONTROL GND TSTAT FT M5608 69-0780 Setting the Heat Fan Off Delay DIP Switches Set the heat fan off delay DIP switches to 60, 100, 140 or 180 seconds as shown in Fig. 3. The off delay is factory-set at 140 seconds. This delay time starts when the main gas valve is de-energized at the end of a thermostat call for heat. Fig. 3—Setting delay off DIP switches. EAC 4 C NEUTRAL N N CIR Checkout Assure the system operates properly by operating the system through at least one complete heating cycle and cooling cycle. Troubleshoot by checking for appropriate voltages at the ST9141A1002 terminals controlling the combustion air blower and heat and cool speed circulating fan. The ST9141A1002 schematic shows internal switching to clarify operation and assist in troubleshooting. See Fig. 2. 3 SEC XFMR LEADS 2 X X BLWR HEAT HUM 2 1 N CONT COOL 1 DI MOTOR 3 UNUSED ST9141 Z1 Z2 DELAY 1 2 OFF SPEED UP C Y G C Y W R ON OFF 1 2 1 2 1 2 60 SECONDS 100 SECONDS 140 SECONDS 1 2 180 SECONDS DELAY OFF DIP SWITCH SETTINGS M5658 ST9141A1002 Operating Sequence Action Thermostat calls for heat. (W terminal is energized.) System Response • Pressure switch confirmed in no airflow position. (If pressure switch shows airflow, LED flashes three times.) • Combustion air blower is energized. • Air proving switch makes (air flow is established). • Ignition system is energized. • Gas valve opens and main burner lights. • Heat fan on delay timing begins. When timing is complete, circulating blower is energized at heat speed. Thermostat ends call for heat. • Ignition system is de-energized and gas valve closes. (W terminal is de-energized.) • Combustion air blower is de-energized after postpurge timing. • Heat fan off delay timing begins. When timing is complete, the circulating fan is de-energized. Thermostat begins call for cool. • Cooling contactor is energized. (G and Y terminals are energized.) • Circulating fan is energized at cool speed after cool fan on delay timing. Thermostat ends call for cool. • Cooling contactor is de-energized. (G and Y terminals are de-energized.) • Circulating fan turns off after cool fan off delay timing. Thermostat begins call for fan. • Circulating fan is energized at heat speed two seconds after G terminal is (G terminal is energized.) energized. • If a call for heat occurs, circulating fan continues to run at heat speed. • If a call for cool occurs, circulating fan switches to cool speed after foursecond delay. Thermostat ends call for fan. • Circulating fan is de-energized. (G terminal is de-energized.) Primary limit switch string opens. • Thermostat and ignition system are de-energized and gas valve closes. • Combustion air blower is de-energized. • Circulating fan is energized at heat speed. • LED flashes twice. • If there is a call for cooling or fan, the circulating fan switches from heat speed to cool speed. (continued) 4 ST9141A1002 Operating Sequence (Continued) Action Primary limit switch string closes. Primary limit switch string is open for more than 150 seconds (on each of three consecutive cycles). Burner limit opens. Burner limit closes. Electronic air cleaner is connected. (Connector to 120 Vac electronic air cleaner.) Humidity control is connected. (Connector to 120 Vac humidifier.) System Response • Circulating fan turns off after the selected heat fan off delay timing. • LED stops flashing. • Normal operation resumes. • Combustion air blower, circulating fan and ignition system are de-energized. • Control goes into lockout mode. • LED flashes four times. • Control remains in lockout until 24V power is removed and reapplied (control is reset). • LED stops flashing. • Normal operation resumes. • Thermostat and ignition system are de-energized and gas valve closes. • Combustion air blower and circulating fan heat speed are energized. • LED flashes once. • Combustion air blower remains energized for postpurge timing. • The circulating fan remains energized for the selected delay off timing. • LED stops flashing. • Normal operation resumes. • Electronic air cleaner is energized when the circulating fan heat or cool speed is energized. • Humidifier is energized when combustion air blower is energized. 5 69-0780 Home and Building Control Honeywell Inc. 1985 Douglas Drive North Golden Valley, MN 55422 Printed in U.S.A. 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