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13
®
Model MSX Make-Up Air
3. Install Suction Line
Install suction line(s) from the compressor to the
suction connection(s) which are stubbed through the
side of the cabinet.
4. Install the Liquid Line and Thermal
Expansion Valve (TEV) (by others)
Liquid line openings vary by coil size and
circuiting and are field supplied. Follow the TEV
recommendations for installation to avoid damaging
the valve. If the valve is externally equalized, use a
tubing cutter to cut off the plugged end of the factory
installed equalizer line. Use a de-burring tool to
remove any loose metal from the equalizer line and
attach it to the TEV. If the valve is internally equalized,
the factory installed equalizer line can be left as is.
5. Mount the Remote Sensing Bulb
(by others)
The expansion valve’s remote sensing bulb should be
securely strapped to the horizontal run of the suction
line at the 3 or 9 o’clock position and insulated.
6. Check Coil Piping for Leaks
Pressurize the coil to 100 psig with dry nitrogen or
other suitable gas. The coil should be left pressurized
for a minimum of 10 minutes. If the coil holds the
pressure, the hook-up can be considered leak free.
If the pressure drops by 5 psig or less, re-pressurize
the coil and wait another 10 minutes. If the pressure
drops again, there is likely one or more small leaks
which should be located and repaired. Pressure losses
greater than 5 psig indicate a large leak that should be
isolated and repaired.
7. Evacuate and Charge the Coil
Use a vacuum pump to evacuate the coil and any
interconnecting piping that has been open to the
atmosphere. Measure the vacuum in the piping using
a micron gauge located as far from the pump as
possible. Evacuate the coil to 500 microns or less,
and then close the valve between the pump and the
system. If the vacuum holds to 500 microns or less
1. Locate the Distributor(s) by Removing
the Distributor Access Panel
Distributor Access Panel
Installation of Direct Expansion (DX)
Coil Piping (optional)
IMPORTANT
Guidelines for the installation of direct expansion
cooling coils have been provided to insure proper
performance and longevity of the coils. These are
general guidelines that may have to be tailored
to meet the specific requirements of any one job.
As always, a qualified party or individual should
perform the installation and maintenance of any coil.
Protective equipment such as safety glasses, steel
toe boots and gloves are recommended during the
installation and maintenance of the coil.
IMPORTANT
All field brazing and welding should be performed
using high quality materials and an inert gas purge
(such as nitrogen) to reduce oxidation of the internal
surface of the coil.
IMPORTANT
All field piping must be self-supporting and flexible
enough to allow for the thermal expansion of the coil.
NOTE
If a hot gas bypass kit was provided by others, refer
to the manufacturer’s instructions.
General Installation
Expansion
Valve (by others)
Liquid Line
Thermal
Nozzle
Suction Header
Coil
Distributor
Equalizer Line
Suction Line
Remote Sensing Bulb
Straps
Suction Connection
2. Verify Nozzle Placement
Inspect the refrigerant
distributor and verify
that the nozzle is in
place. The nozzle is
generally held in place
by a retaining ring or is
an integral part of
the distributor itself.
Retainer
Ring
Nozzle Distributor
Nozzle Placement
(by others)
(by others)
Installation with Hot Gas Bypass
Thermal