To Turn Off Gas To Unit

1- Set thermostat to lowest level.

2- Turn off all electrical power to unit if service is to be performed.

3- Honeywell VR8205 series valve: turn knob on gas

valve 90° clockwise to OFF.

White Rodgers 36E series valves: turn knob on gas valve 180° either way to OFF.

Robertshaw DER2000 series valves: depress knob on gas valve; knob will snap to OFF.

Heating Sequence of Operation

1- When the thermostat calls for heat, the combustion air blower starts immediately.

2- Combustion air inducer proving switch proves blower operation before allowing power to the ignition controller. This switch is factory set and no adjustment is necessary.

3- After prepurge of approximately 30 seconds, the spark ignition is energized and the solenoid valves open in the gas valve.

4- The spark then ignites the gas, the ignition sensor proves the flame and the combustion process continues.

5- In the event that the flame is not detected after the first 10-second trial for ignition, the controller will repeat steps 3 and 4 an additional two times before locking out the gas valve. Ignition control will then automatically repeat steps 3, 4, and 5 after 60 minutes.

To interrupt the 60-minute lockout period, move thermostat from “Heat" to “OFF" then back to “Heat." Heating sequence then restarts at step 1.

6- The burners shall light without noticeable crossover delay. There shall be no flame lifting from the burner heads, flashback or burning within the burner. The flames shall be predominantly blue in color and shall be approximately centered in the tubes with no apparent impingement taking place.

7- The ignition control will energize the fan approximately 45 seconds after ignition is established.

8- After the thermostat demand is satisfied the gas valve is closed; 5 seconds after the demand is satisfied the combustion air blower is shut off.

9- The control center shall shut off the system fan approximately 120 seconds after the gas valve is de-energized.

Ignition Control LED

The ignition control board contains a green LED which indicates the following:

	TABLE 5
	IGNITION CONTROL LED
LED	UNIT OPERATION


Slow	Normal Operation - No call for heat
Flash*
Fast	Normal Operation - Call for heat
Flash	Current signal at FLAME terminal 0.6 to 1.0 microamps
2 Flashes	System lockout - failed to detect or sustain flame
	Current signal at FLAME terminal <0.6 microamps
3 Flashes	Combustion air inducer proving switch failed closed
	before CAB is energized or failed open after CAB is
	energized
4 Flashes	High limit or rollout switch open

5 Flashes	Flame sensed and gas valve not energized

Steady	Loss of power
Off
Steady	Ignition control failure
On

*When thermostat is placed in continuous fan mode LED will slowly flash.

Optional Gas Conversion Kit

A natural to LP/propane gas changeover kit is required to convert unit. Refer to the installation instructions supplied with the changeover kit for conversion procedure.

Page 16

TUA45S, T-CLASS TM SEPARATED COMBUSTION UNIT HEATERS, TUA75S, TUA100S, TUA60S specifications

Lennox International Inc. stands out as a leader in the heating and cooling industry, and its T-Class™ Separated Combustion Unit Heaters, including models such as TUA60S, TUA100S, TUA125S, and TUA45S, epitomize innovation and efficiency. These unit heaters are engineered to provide reliable warmth in commercial and industrial environments, ensuring comfort and productivity even in the coldest conditions.

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Installation is straightforward thanks to their flexible configurations, allowing for both vertical and horizontal venting options. This adaptability makes them suitable for various applications, from warehouses to manufacturing plants.

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In conclusion, Lennox International Inc.’s T-Class™ Separated Combustion Unit Heaters, including the TUA60S, TUA100S, TUA125S, and TUA45S, offer a blend of efficiency, reliability, and advanced technology. These heaters are suitable for a variety of commercial and industrial applications, ensuring optimal comfort while prioritizing safety and energy savings.

Lennox International Inc T-CLASS TM SEPARATED COMBUSTION UNIT HEATERS To Turn Off Gas To Unit

Models: TUA45S T-CLASS TM SEPARATED COMBUSTION UNIT HEATERS TUA75S TUA100S TUA60S TUA125S