Novation™ Coil Cleaning And Maintenance; Repairing Novation Condenser Tube Leaks; Replacing Novation Condenser Coil; Field Refrigerant Access Ports - Carrier 38AU Installation, Start-Up And Service Instructions Manual

NOVATION™ Coil Cleaning and Maintenance —
To clean the NOVATION condenser coil, chemicals are NOT
to be used; only water is approved as the cleaning solution.
Only clean potable water is authorized for cleaning
NOVATION condensers.
Clean the coil as follows:
1. Turn off unit power.
2. Remove screws holding rear corner posts and top cover
in place. Pivot top cover up 12 to 18 in. (305 to 457 mm)
and support with a rigid support. See Fig. 24.
Fig. 24 — Pivot and Support Top Cover
3. Carefully remove any foreign objects or debris attached
to the coil face or trapped within the mounting frame and
brackets.
4. Using a high pressure water sprayer, purge any soap or
industrial cleaners from hose and/or dilution tank prior to
wetting the coil.Clean condenser face by spraying the coil
core steadily and uniformly from top to bottom, directing
the spray straight into or toward the coil face. Do not
exceed 900 psig or a 45 degree angle; nozzle must be at
least 12 in. (30 cm) from the coil face. Reduce pressure
and use caution to prevent damage to air centers (fins).
Do not fracture the braze between air centers and
refrigerant tubes. Allow water to drain from the coil core
and check for refrigerant leaks prior to start−up.
5. Replace top cover and rear corner posts.
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in damage to
equipment.
Chemical cleaning should NOT be used on the aluminum
microchannel (NOVATION) condenser. Damage to the coil
may occur. Only approved cleaning is recommended.

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 fluxcore 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.
Field Refrigerant Access Ports —
access to refrigerant pressures is through the access ports
located at the service valves (see Fig. 8). These ports are ¼-in
SAE Flare couplings with Schrader check valves and service
caps. Use these ports to admit nitrogen to the field tubing
during brazing, to evacuate the tubing and evaporator coil, to
admit initial refrigerant charge into the low-side of the system
and when checking and adjusting the system refrigerant
charge. When service activities are completed, ensure the
service caps are in place and secure; check for leaks. If the
Schrader check valve must be removed and re-installed, tighten
to 2-3 in-lbs (23-34 N-cm).
Factory High-Flow Access Ports —
additional access ports in the system - on the suction tube
between the compressor and the suction service valve and on
the liquid tube near the liquid service valve (see Fig. 8). These
are brass fittings with black plastic caps. The hose connection
fittings are standard ¼-in SAE Male Flare couplings.
The brass fittings are two-piece High Flow valves, with a re-
ceptacle base brazed to the tubing and an integral spring-closed
check valve core screwed into the base. (See Fig. 31) This
check valve is permanently assembled into this core body and
cannot be serviced separately; replace the entire core body if
necessary. Service tools are available from RCD that allow the
replacement of the check valve core without having to recover
the entire system refrigerant charge. Apply compressor refrig-
erant oil to the check valve core's bottom o-ring. Install the fit-
ting body with 96 ±-10 in-lbs (1085 ±23 N-cm) of torque; do
not overtighten.
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Field service
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