Trane GRAA - Lighting

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 b e
exc ee d e d .
Improper
un i t op e
r
a
t i 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 max i 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.
-13-