Optional Direct Expansion (Dx) Coil Piping - Greenheck DG Installation, Operation And Maintenance Manual

Installation of Direct Expansion (DX)
Coil Piping (optional)
IMPORTANT
Guidelines for the installation of direct expansion
cooling coils have been provided to ensure 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.
1. Locate the Distributor(s) by Removing the
Distributor Access Panel
Distributor Access Panel
Installation with Hot Gas Bypass
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.
12 Direct Spark Ignition Make-Up Air
Retainer
Nozzle Distributor
Ring
NOTE
If a hot gas bypass kit was provided by others, refer
to the manufacturer's instructions.
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.
Liquid Line
Equalizer Line
Nozzle
Thermal
Expansion
Valve (by others)
Suction Line
Remote Sensing Bulb
General Installation
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.
Coil
Suction Header
Distributor
Straps
Suction Connection
®