Danfoss MCHE Installation And Maintenance Manual page 4

Sevice guide | Application, Installation and Maintenance Manual MCHE
2. Storage and working
environments
© Danfoss | Climate Solutions | 2024.12
2.1 Storage
Microchannel heat exchangers should be stored
indoors in a dry and clean environment.
The storage temperature range is -40 °C to 121°C
(-40°F to 250°F).
Metal chips, and/or copper or steel dust can
cause galvanic corrosion, so storage and
installation areas must remain clean and
separate from machining or welding areas. Use
separate tools and/or keep tools clean.
To minimize potential damage, we recommend
that you keep MCHEs in their original packaging
until they are installed in the air conditioning or
refrigeration equipment.
Improper storage and stacking of MCHEs can
cause premature corrosion or deformation and
will reduce MCHE's life. Extra care should be
taken when storing MCHEs!
Refrigerants used in MCHE shall comply with
AHRI Standard 700.
The maximum operating pressure shall not
exceed the value shown on the Label of MCHE.
2.2 Handling
Compared to tube & fin coils, microchannel heat
exchangers are relatively light, the fins are harder
to bend and they are less likely to cut fingers. The
combination of these features makes MCHEs
easier to handle than tube & fin coils. However,
the overall coil assembly is made of soft alu-
minum, so it is susceptible to deformation (Fig.1)
Do not lift MCHX in
inlet/outlet pipes
Fig. 1 Handling attentions
Never lift a MCHE by the inlet and outlet tubes as
it might result in dimensional deviation or worse
yet, the initiation of a crack that can later result in
a leak.
Do not hit or drop MCHE on edges.
The MCHE is constructed of soft aluminum
therefore, dropping, striking, placing heavy
objects on top of, or stepping on any part of the
heat exchanger will likely cause a deformation. If
the coil becomes slightly deformed or bowed, it
is possible to flatten them back out by laying
them concave side down on a flat hard surface
and applying pressure via a large heavy flat plate
(say 3-4 square feet of ½" non-metallic sheet,
such as plywood or plastic, with a couple of
handles attached). This procedure works for
bowed coils with flush fins, but not for local fin
protrusions.
2.3 Bending procedure
The same bending machines can be used for
MCHE and tube & fin heat exchangers. In order to
optimize costs associated with shipping and
packaging, we recommend that MCHEs be
shipped flat and formed at the customer's
location.
Bending Radius:
The minimum bend radius required to achieve
acceptable manufacturing yields is a function of
the microchannel tube, fin, and alloy, the overall
capabilities of the bending equipment including,
fixturing, bending speed and bending length.
NOTE: Conducting trial bending runs of the
specific coil and configuration are recommended
to verify. In general, tighter radius, thicker tubes
and longer bend lines are harder to bend. Use a
larger radius if possible.
Recommended minimum bending radii (as
determined by factory tests under favorable
conditions) are shown in Table 1 for different
microchannel tubes and fins. Consult with
Danfoss for the tubes not listed. Do not
arbitrarily extrapolate or interpolate the values.
2.4 Bending Time and Temperature
Limitation
No bending time and temperature limitation on
BARE MCHE. While for coated MCHE, long
warehoused time and low temperature shall
reduce the epoxy coating's elasticity may result
coating cracking. To assure optimum corrosion
protection and coating layer integrity on formed
MCHE requires:
• Coils shall be bent within 6 months of
coating,
• Metal and coating temperature shall be
greater than 16 °C (60 °F) at time of
bending,
• Coating shall be protected from abrasion,
gouges, and impact before and during the
bending process,
• Inspect coil geometry and appearance
after bending to conformity drawings and
specification requirement.
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