Greenheck DGX Installation, Operation And Maintenance Manual page 17

Installation - Chilled Water Coil Piping (Optional)
Guidelines for the installation of the cooling coil have been provided to insure proper performance of
the coils and their longevity. 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 the coil. Protective equipment such as safety glasses, steel toe boots
and gloves are recommended during the installation and maintenance of the coil.
IMPORTANT!
When installing couplings, do not apply undue
stress to the connection. Use a backup pipe
wrench to avoid breaking the weld between the
coil connection and the header.
Step 1 Verify Coil Hand Designation
Check the coil hand designation to insure that it
matches the system. Coils are generally plumbed with
the supply connection located on the bottom of the
leaving air side of the coil and the return connection
at the top of the entering air side of the coil. This
arrangement provides a counter flow heat exchanger
and positive coil drainage. See figure #33
Step 2 Check the Coil 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.
Step 3 Connect the Supply and Return Lines
Connect the supply and return lines. Refer to figure #33.
Step 4 Install the Drain Line
Connect an unobstructed drain line to the drain pan.
A trap should be installed to prevent sewer gas from
being drawn into the unit. See figure #34.
IMPORTANT!
All traps must be installed below the roofline or
be otherwise protected from freezing.
IMPORTANT!
All field piping must be self supporting. System
piping should be flexible enough to allow for the
thermal expansion and contraction of the coil.
Hot Return
Connection
Entering Air
Figure 33. Coil Connections
17
IMPORTANT!
Leaving Air
Cold Supply
Connection
6 in. min.
Figure 34. Drain Trap
6 in. min.