Trane GRAA Installation, Operation And Maintenance Manual page 34

O O p p e e r r a a t t i i o o n n
the limit set point, normally caused by insufficient air throughput, all gas is shutoff. The limit
control has an automatic reset and once the unit has cooled, it will reset itself. This is a safety
control and if cycling on the primary limit is noted, corrective action must be taken. See unit
wiring diagram for electrical location. This control must never be bypassed. Upon completion of
unit installation, the primary limit must be checked for proper operation. This can be
accomplished by removing power to the indoor air blower and a call for heat.
D D r r a a f f t t o o r r E E n n d d S S w w i i t t c c h h ( ( P P o o w w e e r r v v e e n n t t e e d d u u n n i i t t s s o o n n l l y y ) ) : : This switch is located at the end of the draftor
motor and is integral to the motor. The switch, which is normally open, will close when draftor
motor attains the minimum speed for proper combustion allowing main burner operation. The
pilot burner will light without a proven draftor end switch. See unit wiring diagram for electrical
location.
C C l l o o g g g g e e d d F F i i l l t t e e r r S S w w i i t t c c h h : : (Optional) The clogged filter switch monitors the pressure differential
across the air filters. If this pressure differential becomes too great, the switch will alert of this
condition. At this point the air filters must either be cleaned or replaced. The switch will reset
itself.
F F i i r r e e s s t t a a t t : : (Optional) Located in either the return airstream, the supply airstream, or both, this
control monitors temperatures with set points which are field adjustable. If the temperature
exceeds the set point, the control will cease unit operation. To resume unit operation, a manual
reset of this control is required.
F F r r e e e e z z e e s s t t a a t t : : (Optional) Located in either the return airstream, the supply airstream, or both, this
control monitors temperatures with set points which are field adjustable. If the temperature does
not exceed the set point, the control will cease unit operation.
34 MUA-SVX003B-EN