Lighting - Trane GRAA Installation Operation & Maintenance

Static Pressure through the unit should never exceed
2.0" W.C. (0.50 kPa). The standard unit is operated at
a temperature rise range of 20 to 60 F° (11 to 33 CO).
The high temperature rise model is operated at a
temperature rise range of 60 to 90 F° (33 to 50 CO).
NOTE : It is important that the final temperature
leaving the unit does not exceed 160 0 F (71 ° C) .
When final air throughput adjustments are being
made , a check of the discharge air temperature
should be made after unit has operated for 15 to
20 minutes .
CAUTION : A unit should never be allowed to
cycle on the primary limit for a prolonged period
of time . It is a safety control to prevent a fire . If
cycling on the primary limit is noted , corrective
measures should be taken immediately. Failure
to do so could result in unit damage or a fire .
NOTE : At initial unit installation , unit should be
started momentarily to confirm proper blower
wheel rotation as the unit will deliver some air
with the blower wheel running backwards .
Two basic air control systems can be used to deliver
conditioned air to the occupied space: intermittent or
constant fan operation.
Intermittent Fan Operation : The unit employs an air
control system which utilizes a fan time delay relay to
operate the fan while heating and the thermostat
while cooling. Refer to unit wiring diagram.
Constant Fan Operation: The unit can be wired to
give an air control system which constantly circulates
air through the unit and occupied space with con-
stant fan operation. Refer to unit wiring diagram.
NOTE: Check blower belt tension. Proper belt
tension is important to the long life of the belt
and motor. Proper belt tension will allow the belt
to be depressed 1/2" to 3/4".
It is important that the blower motor and the blower
wheel pulleys be in good alignment, with the motor
and blower shafts parallel.
Belt tension must be adjusted to give approximately
3/4" deflection of the belt when finger pressure is
applied to the middle of the belt (See Figure 10).
Small changes in this tension may be necessary for
optimum operation. Belts will stretch over a period of
time, requiring an adjustment to this tension. See
MAINTENANCE section for belt and pulley adjust=
ments.
These units are set at the factory for the RPM
required to meet the air volume (CFM) and external
static pressure ordered. If the estimated external sta-
tic is incorrect, or changes were made to the duct
system, the blower RPM may need to be changed.
Both the Standard and High CFM Blowers use
motors which are equipped with adjustable pitch pul-
leys. After removing belt(s), loosen the pulley set
screw and remove the key, turn adjustable half of a
pulley clockwise to increase RPM, or counter-clock-
wise to decrease RPM. Insert key, tighten set screw
and replace belt(s). Adjust belt tension to give 1/2" to
3/4" belt play when depressed.
CAUTION : Blower motor fu l l load amps should
never be excee d e d . Improper un i t operati on or
motor failure could result .
After changing blower RPM, confirm blower motor
full load amps have not been exceeded . See motor
data plate for maxi mum full load amps .
L I GHT I NG
(Refer to Outdoor Duct Furnace Manual for all heat-
ing functions - general comments are as follows.)
Purge the gas line to the unit of air before attempting
to light the pilot. Check for gas leaks.
This unit is equipped with an intermittent ignition sys-
tem. A lighting instruction is attached to the unit. To
set the intermittent ignition system into operation
proceed as follows:
1. Turn on the gas valve(s) main manual valve.
2. Turn on electrical power. The unit is now under
thermostat control.
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