Trane Gas Unit Heaters Katalog

30

 UH-PRC002-EN

High efficiency units (centrifugal, propeller and duct furnaces) ship as standard with intermittent 
pilot ignition. The separated combustion propeller and centrifugal fan unit heaters also ship as 
standard with intermittent pilot ignition.

Intermittent pilot ignition contains a solid-state ignition control system that ignites the pilot by 
spark for each cycle of operation. When the pilot flame is proven, the main burner valve opens to 
allow gas flow to the burners. Both the pilot and burners are extinguished during the off cycle.

Intermittent pilot ignition is ideal for limited access installations where manual lighting of the pilot 
may be difficult. Nuisance pilot outages on units mounted in areas subject to occasional severe 
drafts can also be eliminated. Energy savings will be realized using this system as the pilot is 
extinguished during the off cycle. Intermittent pilot ignition should be considered on units that 
have long shutoff periods.

The supply fan motor is activated directly through the fan time delay relay on indoor units provided 
with single-phase motors up to one hp. Contactors or starters are required on all other units with 
single-phase motors, 1-1/2 hp and above, and with all three-phase motors. On indoor units, 
contactors and starters, where required, are provided (see 

.)

Indoor gas heating units are provided with an automatic single-stage gas valve as standard. This 
valve is an on/off type control, typically activated by a low voltage single-stage thermostat.

Indoor units with optional two-stage control are provided with a two-stage gas valve capable of 
firing at 100 percent and 50 percent of rated input. Ignition is at low fire (50 percent of the unit’s rated 
input) and the unit is typically controlled by a low voltage two-stage thermostat.

This optional control is available for use with natural gas units only. Units with electronic 
modulating control are provided with an electronic modulating valve capable of firing from 100 
percent to 50 percent of rated input. Ignition is at full fire (100 percent of unit’s rated input). The 
electronic modulating valve is controlled by a room thermostat or a duct thermostat with remote 
setpoint adjustment which modulates the gas input from 100 percent to 50 percent of rated input. 
An optional override room thermostat is available for use with the duct thermostat. The override 
room thermostat allows full fire and overrides the duct thermostat when the room temperature 
falls below the override room thermostat’s setpoint.

115/60/1

1

1

1

2

2

N/A

N/A

N/A

N/A

230/60/1

1

1

1

2

2

N/A

N/A

N/A

N/A

208/60/3

2

2

2

2

2

2

2

4

4

230/60/3

2

2

2

2

2

2

2

4

4

460/60/3

3

3

3

3

3

3

3

5

5

 1. Contactors not required or provided on units with single phase motors up to one hp.

 2. Provided with contactor with line voltage holding coil on all 1-1/2 hp and above single-phase motors and on all 208/230V 

three-phase motors up to five hp.

 3. Provided with contactor with low (24V) holding coil on all 460 V three-phase motors up to five hp.

 4. Provided with size 2 starter on all units with 7-1/2 and 10 hp 208/230V three-phase motors.

 5. Provided with size 1 starter on all units with 7-1/2 and 10 hp 460V three-phase motors.