Lennox International Inc. TUA125S Benutzerhandbuch

Seite von 21
Page 12 
 
 6- After it has been determined that each appliance 
remaining connected to the common venting system 
properly vents when tested as outlined above, return  
doors, windows, exhaust fans, fireplace dampers 
and any other gas-burning appliance to their 
previous condition of use.  
7-  If improper venting is observed during any of the 
above tests, the common venting system must be 
corrected. The common venting system should be 
resized to approach the minimum size as 
determined by using the appropriate tables in 
Appendix G in the current standards of the National 
Fuel Gas Code, ANSI Z223-1 in the U.S.A. and the 
appropriate Category I Natural Gas and Propane 
appliances venting sizing tables in the current 
standards of the CSA-B149.1 and .2 in the Natural 
Gas and Propane Installation Code in Canada. 
NOTE - Local codes may supersede any of the above 
provisions. 
 
Electrical Connections 
 
NOTE - These unit heaters use a direct spark ignition 
system. There is no pilot necessary as the spark lights 
the main burner as the gas valve is turned on. The direct 
spark ignition control board emits radio noise as the 
sparking process is underway. The level of energy may 
be sufficient to disturb a logic circuit in a microprocessor 
controlled thermostat. It is recommended that an 
isolation relay be used when connecting the unit heaters 
to a microprocessor controlled thermostat. Install the 
thermostat according to instructions provided. Select 
circuit protection and wire size according to the unit 
rating plate. Install a separate disconnect switch 
(protected by either fuse or circuit breaker) near the unit 
so that power can be turned off for servicing. Connect 
wiring through knockout on the junction box located on 
the side of the unit heater. Refer to heater wiring 
diagram for connection information. Use 18 gauge wire 
or larger for thermostat connections. 
Electrically ground unit in accordance with local codes 
or, in the absence of local codes, in accordance with the 
current National Electrical Code (ANSI/NFPA No. 70) in 
the U.S.A., and in Canada with the current Canadian 
Electrical Code, Part 1 (CSA C22.1). 
Make line voltage connections as shown in figure 8. 
Connect field wiring as shown on wiring diagram on 
unit. Also refer to typical diagram in this manual. An 
additional thermostat wire must be run to terminal “G" 
on heater when continuous blower is desired. 
 
FIGURE 8 
LINE VOLTAGE FIELD WIRING
L1
WHITE
N
BLACK
UNIT ELECTRICAL BOX