The Tech 4 True Blue 90 is a high-efficiency gas furnace with 90% AFUE rating, featuring advanced combustion technology, electronic ignition, variable-speed blower motor, multi-speed operation, built-in diagnostics, safety controls, and compatibility with standard thermostat systems. Designed for residential heating applications with natural gas or propane capability. Below are key sections for safety, features, installation, operation, maintenance, and troubleshooting.
Key components: Heat exchanger, blower assembly, gas valve, ignition control, pressure switches, flame sensor, limit switches, diagnostic LED.
| Feature | Description |
|---|---|
| AFUE Rating | 90% Annual Fuel Utilization Efficiency |
| Ignition System | Hot Surface Ignition (HSI) |
| Blower Motor | Variable-speed ECM motor |
| Gas Type | Natural gas or propane (field convertible) |
| Heat Exchanger | Stainless steel primary and secondary |
| Controls | Integrated furnace control board |
| Diagnostics | LED status indicator with flash codes |
| Safety Features | Rollout switches, pressure switches, limit controls |
| Venting | PVC pipe compatible |
| Warranty | 20-year heat exchanger limited warranty |
Read all safety instructions before installation or service.
WARNING! Carbon monoxide hazard - ensure proper venting and combustion air supply. Install CO detectors in living areas.
Professional installation required. Verify location meets clearance requirements.
CAUTION! Do not install in corrosive atmosphere or where exposed to chemicals.
Integrated control board manages all furnace functions. Access door switch must be closed for operation.
Thermostat Connections: R, C, W, G, Y terminals standard.
Operation Sequence: Call for heat → Inducer motor starts → Pressure switch proves → Hot surface ignition → Gas valve opens → Flame sensed → Blower starts after delay.
Blower Speeds: Cooling: High speed; Heating: Multiple heat speeds; Continuous fan: Low speed.
Category IV venting required. Use PVC, CPVC, or ABS pipe.
Tip: Use primer and cement approved for plastic pipe.
Disconnect power before servicing.
WARNING! Electrical shock hazard - disconnect power before accessing electrical components.
Gas line installation by qualified professional only.
WARNING! Gas explosion hazard - test all connections for leaks before operation.
Annual maintenance recommended by qualified technician.
CAUTION! Turn off gas and electrical power before maintenance.
LED flash codes indicate system status and faults.
| Flash Pattern | Description | Action |
|---|---|---|
| 1 Flash | Normal operation | No action required |
| 2 Flashes | Pressure switch fault | Check venting and switches |
| 3 Flashes | Ignition failure | Check HSI and gas supply |
| 4 Flashes | Flame sense failure | Clean flame sensor |
| 5 Flashes | Rollout switch open | Check for restricted venting |
| 6 Flashes | Limit circuit fault | Check airflow and filters |
| 7 Flashes | Blower fault | Check motor and capacitor |
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Furnace won't start | Power, thermostat, door switch | Check power supply, thermostat setting, door switch engagement |
| No heat | Gas supply, ignition | Verify gas valve on, check for ignition attempts |
| Short cycling | Dirty filter, airflow | Replace filter, check for blocked vents/registers |
| Blower won't stop | Thermostat fan setting | Check thermostat fan setting (auto/on) |
| Unusual noises | Motor, blower wheel | Inspect blower assembly, motor bearings |
| Condensate leak | Drain line blockage | Clear condensate drain line and trap |
Reset: Power cycle furnace to clear temporary lockouts.
Service: Contact qualified HVAC technician for complex issues.