Sensor Re-Installation; Maintenance Of Painted Surfaces; Composite Control Box Repairs; Introduction - Carrier 69NT40-489-100 Series Operation And Service Manual

h. Slip crimp fittings over dressed wires (keeping wire
colors together). Make sure wires are pushed into
crimp fittings as far as possible and crimp with crimp-
ing tool. Cap off unused red/white wire if replacing a
two wire sensor with a three wire sensor
i. Solder spliced wires with a 60% tin and 40% lead
Rosincore solder.
j. Slide heat shrink tubing over splice so that ends of
tubing cover both ends of crimp as shown in
Figure 48.
k. Heat tubing to shrink over splice. Make sure all seams
are sealed tightly against the wiring to prevent mois-
ture seepage.
l. Slide large heat shrink tubing over both splices and
shrink.
CAUTION
Do not allow moisture to enter wire splice
area as this may affect the sensor resis-
tance.
m. Reinstall sensor, refer to section 6.22.3, page 77.
NOTE
The P5 Pre-Trip test must be run to inactivate
probe alarms (refer to section 4.8, page 47).

6.22.3 Sensor Re-Installation

a. Sensors STS/SRS
To properly position a supply sensor, the sensor must be
fully inserted into the probe holder. This positioning will
give the sensor the optimum amount of exposure to the
supply air stream, and will allow the Controller to
operate correctly. Insufficient probe insertion into the
probe holder will result in poor temperature control due
to the lack of air flow over the sensor.
It is also necessary to ensure that the probe tip does not
contact the evaporator back panel. The design
minimum clearance of 6 mm (1/4 inch) should be
maintained (see Figure 49).
b. Sensor RTS/RRS
Reinstall the return sensor as shown in Figure 50, page
77. For proper placement of the return sensor, be sure to
position the seal section of the sensor against the the
side of the mounting clamp.
c. Sensor DTS
The DTS sensor must have insulating material placed
completely over the sensor to insure the coil metal
temperature is sensed.
Sensor
Wires
Probe
Holder
Supply Sensor

Figure 49. Supply Sensor Positioning

Seal

Figure 50. Return Sensor Positioning

6.23 MAINTENANCE OF PAINTED SURFACES

The refrigeration unit is protected by a special paint
system against the corrosive atmosphere in which it
normally operates. However, should the paint system
be damaged, the base metal can corrode. In order to
protect the refrigeration unit from the highly corrosive
sea atmosphere, or if the protective paint system is
scratched or damaged, clean area to bare metal using a
wire brush, emery paper or equivalent cleaning method.
Immediately following cleaning, spray or brush on
zinc-rich primer. After the primer has dried, spray or
brush on finish coat of paint to match original unit color.

6.24 COMPOSITE CONTROL BOX REPAIRS

6.24.1 Introduction

This procedure provides instructions for repair of the
Carrier Transicold composite control box. Damage to
the control box may be in the form of a chip or hole, a
crack, a damaged thread insert or damage to the door
hinge inserts. Generally, the object of the repair must be
to ensure sufficient strength is restored to the damaged
area and the repair must keep the box water tight.
Information on repair kits and repair procedures for each
type of damage is provided in the following paragraphs.
Ambient temperature must be above 7°C (45°F) for
proper curing of epoxy repairs.
77
Cap and Grommet
Assembly
Evaporator
Back Panel
Supply
Air
Stream
6 mm
(1/4 inch)
Evaporator Grille
Combination
Sensor (Mount in
Either Clamp)
Mounting
Clamp
T-305