Carrier 50BA - Manual (Page 22)

Access Panel Removal — On Size 004-012 units,
remove return air grille as described above. Remove
remaining grille side frame. Remove the panel
fastening screws now exposed.
TOP PANEL — Pull out and down.
BOTTOM PANEL — Pull out and up.
Indoor-Air Fan Motor Removal
A CAUTION
Before. aiiempttiJg:.to Totnove, faxt .ariotorjs.. of
motor mounts., p&ce a piece of piywo
evaporator coiis to prevent coil damage,
50BA,BB004 THRU 012 — Motor power wires
need not be disconnected from motor terminals
before motor is removed from unit.
1. Shut off unit main power supply.
2. Loosen motor holddown bolts on mounting
bracket so that fan belt can be removed.
3. Loosen but do not remove the 2 motor mounting
bracket bolts on left side of bracket.
4. Slide motor/bracket assembly to extreme right
and lift out thru space between fan scroll and
side frame. Rest motor on a high platform such
as a step ladder. Do not allow motor to hang
by its power wires.
Field-Supplied Motors — The factory-installed
mounting bracket for a 48 frame motor will not fit
a 56 frame motor. If replacing 48 frame motor with
56 frame motor, use mounting bracket for 56 frame
motor.
50BA,BB016 AND 024 — Remove motor as
Follows:
1. Remove unit access panel and cover of motor
junction box.
’. Disconnect motor wires and remove conduit
connection.
. Remove motor base bolts and slide motor over so
that fan belt can be removed.
. Disconnect motor ground wire and remove
motor.
3BA,BB028 AND 034 — Proceed as follows:
Remove unit access panel and motor junction
box cover.
Disconnect motor wires and remove conduit
connection.
Remove the 2 motor adjusting screws and the fan
belt.
Slide motor assembly out thru slots in mounting
angles.
BA,BB044 THRU 064 — To remove motor:
Remove unit access panel and motor junction
box cover.
Disconnect motor wires and remove conduit
connection.
Remove bolts holding motor mounting plate to
channels.
Back out the motor adjusting screws, remove the
an belt and slide motor out thru channel lip
’uides.
TO REINSTALL MOTORS — Reverse the above
procedures. Align pulleys and adjust belt tension
as described in the section, Indoor-Air Fan
Adjustment.
Pressure Relief Devices — The 50BB (con­
denserless) units are equipped with a fusible-plug
type safety relief device on the compressor. The
relief setting is 197 or 203 F on all units.
All 50BA (water-cooled) units, except Size
50BA064, have a frangible disc on each condenser.
Disc setting is 385 ± 5% psig.
The 50BA064 unit has a condenser pressure relief
valve set at 385 psig plus a pressure relief valve
on the compressor set at 450 psig.
Crankcase Heaters are supplied on all 50BB
(condenserless) units and on 50BA008 and 064
water-cooled units.
The heater prevents liquid refrigerant from accu­
mulating in the compressor crankcase during
extended shutdown periods. Heater is automatically
energized whenever unit main power is on and
compressor is stopped. Heater is de-energized when
compressor starts.
Do not shut off unit main power supply for an
extended period except for servicing unit. Turn
on power supply for at least the following time
interval after an extended shutdown before starting
compressor:
7”'’7”50BB504,00^ 1 —— --“g-r
ЪоВАООа and“064
^OBBOOS thru 064
‘Refer to Start-Up procedures
If 50BA units are installed in unheated rooms,
they should be equipped with crankcase heaters.
High and Low Pressurestats — Refer to Table I
for cut-in and cutout settings for these safety
devices.
The high pressurestat is located in the electrical
panel. The low pressurestat is located on top of
compressor except as follows.
50BA008 unit — on suction line
50BA,BB064 units — in electrical panel
Time Guard® Control Circuit provides automatic
reset protection (except circuit breaker), time delay
in starting and controlled cycling. If compressor
shuts down for any reason, the control circuit pre­
vents restart for time periods as follows:
24 hrs
UNIT
50BA.BB
CIRCUIT
NO
77.'
Full Cycle
(minutes)
"“'‘в/_/_/_
Delayed Start
(seconds)
ooi.ma '
016
1 5 15
044,054
2
1 and 3
6 4
5 15
024,028. 1 ' “'6'4 19
034.064 2 5 15
t
ij
Column B shows time delay between compressor
starts under normal thermostat cycling.
For unit Size 016 thru 064 sequence of operation,
see Table 11. This table is useful in troubleshnntioQ