Bryant F - Manual (Page 35)

35
CONDENSER COIL SERVICE
Condenser Coil
The condenser coil is new NOVATION Heat Exchanger
Technology. This is an all--aluminum construction with
louvered fins over single--depth crosstubes. The crosstubes
have multiple small passages through which the
refrigerant passes from header to header on each end.
Tubes and fins are both aluminum construction.
Connection tube joints are copper. The coil may be
one--row or two--row. Two--row coils are spaced apart to
assist in cleaning.
Repairing NOVATION Condenser Tube Leaks
RCD offers service repair kit Part Number 50TJ660007
for repairing tube leaks in the NOVATION coil crosstubes.
This kit includes approved braze materials (aluminum flux
core braze rods), a heat shield, a stainless steel brush,
replacement fin segments, adhesive for replacing fin
segments, and instructions specific to the NOVATION
aluminum coil. See EPIC for instruction sheet
99TA526379.
The repair procedure requires the use of MAPP gas and
torch (must be supplied by servicer) instead of
conventional oxyacetylene fuel and torch. While the
flame temperature for MAPP is lower than that of
oxyacetylene (and thus provides more flexibility when
working on aluminum), the flame temperature is still
higher than the melting temperature of aluminum, so user
caution is required. Follow instructions carefully. Use the
heat shield.
Replacing NOVATION Condenser Coil
The service replacement coil is preformed and is equipped
with transition joints with copper stub tubes. When
brazing the connection joints to the unit tubing, use a wet
cloth around the aluminum tube at the transition joint.
Avoid applying torch flame directly onto the aluminum
tubing.
RTU--MP CONTROL SYSTEM
The RTU--MP controller provides expanded stand--alone
operation of the HVAC system plus connection and
control through communication with several Building
Automation Systems (BAS) through popular third--party
network systems. (See Fig. 42.) The available network
systems are BACnet MP/TP, Modbus and Johnson J2.
Communication with LonWorks is also possible by adding
an accessory interface card to the RTU--MP. Selection of
the communication protocol and baud rate are made at
on--board DIP switches.
Bryant’s diagnostic display tools BACviewer6 Handheld
and Virtual BACview (loaded on a portable PC) must be
used with the RTU--MP controller. Connection to the
RTU--MP board is at the J12 access port. (See Fig. 42.)
The RTU--MP control is factory--mounted in the 48TC
unit’s main control box, to the left of the LCTB. (See Fig.
43.) Factory wiring is completed through harnesses
connected to the LCTB. Field connections for RTU--MP
sensors will be made at the Phoenix connectors on the
RTU--MP board. The factory--installed RTU--MP control
includes the supply--air temperature (SAT) sensor. The
outdoor air temperature (OAT) sensor is included in the
FIOP/accessory EconoMi$er 2 package.
Refer to Table 15, RTU--MP Controller Inputs and
Outputs, for locations of all connections to the RTU--MP
board.
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