| Universal Electronic Fan Timer.
Application:
The ST9120U Universal Electronic Fan Timers integrate
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
ST9120U are to monitor the thermostat for heat, cool and
fan demands, run the induced draft blower motor and run
a circulating fan (up to two speeds) as required. The
electronic fan timers also monitor limit switch strings and
energize separate ignition control systems through spst
pressure switches. The ST9120U can replace any
ST9101 or ST9120 listed in Table 2 below. The electronic
fan timers feature a field-adjustable heat fan-on delay, a
field-adjustable heat fan-off delay, a field-adjustable cool fan-on delay and a fixed cool fan-off delay.
Electronic air cleaner and humidifier convenience terminal connections are provided as an option. Continuous low speed indoor air circulation is also provided.
Technical Specifications:
Electrical Ratings:
Power Voltage Requirements: 18 to 30 Vac, 60 Hz.
Contact Ratings:
Combustion Blower:
1.5A full load, 10A locked rotor at 115 Vac.
0.75A full load, 5A locked rotor at 230 Vac.
(Reduce full load rating by humidifier [HUM] 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 [EAC]
load.)
Continuous speed (optional):
8A full load, 16A locked rotor at 115 Vac.
4A full load, 8A locked rotor at 230 Vac.
EAC and HUM: 0.8A maximum combined load at 115
Vac.
Thermostat Load: 0.10A plus ignition system load.
On/Off Delay Settings:
Heat Speed:
Delay On: Field-adjustable, 30 or 60 seconds. Delay
timing starts when gas valve is energized.
Delay Off: Field-adjustable, 60, 100, 140 or 180 seconds.
Delay timing starts when gas valve is deenergized.
Cool Speed:
Delay On: Field Adjustable, 4 or 30 seconds.
Delay Off: Fixed, 30 seconds.
Timing Tolerance: Larger of ±5% or ±2 seconds.
Post Purge Timing:
5 seconds.
Environmental Ratings:
Temperature: -40°F (-40°C) to +175°F (+79°C).
Humidity: 5 to 95 percent, noncondensing.
Replaces Part Numbers:
ST9101; ST9120; ST9141; ST9160;
ST9120U1011;
ST9101A1006;
ST9101A1014;
ST9101A1022;
ST9120A1006;
ST9120A2004;
ST9120B1005;
ST9120C1012;
ST9120C1020;
ST9120C2002;
ST9120C2010;
ST9120C2028;
ST9120C3000;
ST9120C3018;
ST9120C4008;
ST9120C4016;
ST9120C4040;
ST9120C4057;
ST9120C5005;
ST9120C5013;
ST9120D3009;
ST9120G2008;
ST9120G2016;
ST9120G2024;
ST9120G2032;
ST9120G4004;
ST9120G4012;
ST9120G4038;
ST9120U1003;
ST9141A1002;
ST9141A1028;
ST9141B1001;
ST9150A1003;
ST9150B2000;
ST9150B2018;
ST9150B2026;
ST9150B2034;
ST9150C4057;
ST9160A1002;
ST9160B1001;
ST9160B1035;
ST9160B1043;
ST9160B1050;
ST9160B1068;
ST9160B1076;
ST9160B1084;
ST9160C1000;
ST9160C1018;
ST9160B1019;
ST9160B1027.
Used in Nordyne Models:
G2RR125C20 and many others. |
