COIL TYPES
1. Heatcraft coil model CN is used for applications where
capacity control is not required for a single compressor circuit.
2. Face control (model CF) is another coil option offered. Face
control is the simplest form of capacity control. Type CF
coils are normally furnished with two or more hot gas
connections and two or more liquid connections offering
various capacity reduction capabilities.
INSTALLATION
1. Carefully remove the coil from the shipping package to
avoid damage to the finned area. Damaged fins can be
straightened using an appropriate fin comb.
2. Modine recommends cleaning the coil with a commercially
available coil cleaner prior to installation. Refer to
Maintenance for cleaning recommendations.
3. Proper clearance should be maintained between the coil and
other structures such as the fan, guards, transition areas, etc.
4. All field brazing and welding should be performed using high
quality materials and an inert gas purge (such as nitrogen) to
reduce contamination by oxidation of the internal surface of
the coil.
5. Connect any fittings, valves, and bypass lines to the coil.
6. Modine recommends vibration suppressors between the
incoming hot gas and the compressor to guard against stress
cracks in the connections and brazed joints.
7. Pressurize the coil, bypass line (if any), and connections to
100 psig with dry nitrogen or other suitable gas. The coil
should be left pressurized for a minimum of 10 minutes.
8. If the pressure does not change, the hook-up can be
considered leak free. If the pressure drops by 5 psi or less,
repressurize the coil and wait another 10 minutes. If the
pressure drops again, there are more than likely one or more
small leaks, which should be located and repaired. Be sure to
check valves and fittings as potential sites for leakage or bleed.
If the coil is found to be leaking, contact your local Modine
Heatcraft coil representative. Unauthorized repair of the coil
may void the coil’s warranty.
9. Use a vacuum pump to evacuate the coil and any
interconnecting piping that has been open to atmosphere.
Measure the vacuum in the piping using a micron gauge
located as far from the pump as possible (the vacuum at
the pump will be greater than the rest of the system).
Evacuate the coil to 500 microns or less then close the valve
between the pump and the system. If the vacuum holds to
500 microns or less for one minute, the system is ready to be
charged or refrigerant pumped down in another portion of
the system can be opened to the coil. A steady rise in microns
would indicate that moisture is still present and that the coil
should be further vacuumed until the moisture has been
removed.
10. Failure to obtain a high vacuum is indicative of a great deal
of moisture or a small leak. Break the vacuum with a charge
of dry nitrogen or other suitable gas and recheck for leaks
(soapy water works well). If no leaks are found, continue
vacuuming the coil until the desired vacuum is reached.
11. All field piping must be self-supporting.
12. Refer to Figure 2 - General Diagram, for general plumbing.
Figure 2 - General Plumbing
INSTALLATION, OPERATION AND MAINTENANCE
OPERATION
1. Proper air distribution is vital to coil performance. Airflow
anywhere on the coil face should not vary by more than
20%.
2. Air velocities should be maintained at 400 feet per minute
or above to insure proper heat transfer.
MAINTENANCE
1. Periodic inspection of the coil for signs of corrosion and
for leaks is recommended. Small leaks can be detected
using a Halide torch. Repair and replacement of the coil
and the connecting piping, valves, etc., should be
performed as needed by a qualified individual(s).
2. Routine cleaning of the coil surface is needed to maintain
optimum performance. Caution should be exercised in
selecting the cleaning solution as well as the cleaning
equipment. Use of high-pressure water can cause
damage to the fin surface. Low-pressure water is
recommend when cleaning the coil. Improper selection
can result in damage to the coil and/or health hazards.
Clean the coil from the leaving airside so that foreign
material will be washed out of the coil rather than pushed
further in. Be sure to carefully read and follow the
manufacturer’s recommendations before using any cleaning
fluid.
3. The use of filter-dryers in the system piping is
recommended. Replace the filter dryer(s) as needed.
Note: Refrigerant conversions are beyond the scope of this manual
and should only be performed by qualified parties.
