Category Archives for Furnace
Lennox Pulse Furnace Troubleshooting
Troubleshooting procedures for the Lennox Pulse furnaces are shown in Fig. 2-20. Figure 2-21 shows the circuitry for the G-14Q series of furnaces. Note the difference in the electrical circuitry for the G-14 and GSR-14. Blower speed color-coded wires are … Continue reading
High-Efficiency Furnaces Combustion Process
The process of pulse combustion begins as gas and air are introduced into the sealed combustion chamber with the spark plug igniter. Spark from the plug ignites the gas-air mixture, which in turn causes a positive pressure buildup that closes … Continue reading
High-Efficiency Furnaces Sequence of Operation
On a demand for heat, the room thermostat initiates the purge blower operation for a prepurge cycle of 34 s, followed by energizing of the ignition and opening of the gas valve. As ignition occurs the flame sensor senses proof … Continue reading
High-Efficiency Furnaces Electrical Controls
The furnace is equipped with a standard-type redundant gas valve in series with a gas expansion tank, gas intake flapper valve, and air intake flapper valve. Also factory installed are a purge blower, spark plug igniter and flame sensor with … Continue reading
High-Efficiency Furnaces Operation
The high-efficiency furnaces achieve that level of fuel conversion by using a unique heat-exchanger design. It features a finned cast-iron combustion chamber, temperature-resistant steel tailpipe, aluminized steel exhaust decoupler section, and a finned stainless-steel tube condenser coil similar to an … Continue reading
High-Efficiency Furnaces
Furnaces have been designed (since 1981) with efficiencies of up to 97 percent, as compared to older types with efficiencies in the 60 percent range. The Lennox Pulse is one example of the types available. The G14 series pulse combustion … Continue reading
Hot Air Furnace Circuit Board Control Center
Newer hot-air furnaces feature printed circuit control. The board shown in Fig. 2-8 is such that it is easy for the technician installing the furnace to hook it up properly for the first time. The markings are designed for making … Continue reading
Hot Air Furnace Thermostat Location
The room thermostat should be located where it will be in the natural circulating path of room air. Avoid locations where the thermostat is exposed to cold-air infiltration, drafts from windows, doors, or other openings leading to the outside, or … Continue reading
Hot Air Furnace Low-Voltage Wiring
Make the field low-voltage connections at the low-voltage terminal strip shown in Fig. 2-7. Set the thermostat heat anticipator at 0.60 A (or whatever is called for by the manufacturer). If additional controls are connected in the thermostat circuit, their … Continue reading
Hot Air Furnace Field Wiring
The installation of a new furnace requires you to follow a factory diagram furnished in a booklet that accompanies the unit. The wiring to be done in the field is represented by the dotted lines in Fig. 2-7. All electrical … Continue reading