13. Re-attach the grommets to the lines carefully to
prevent air leakage. In some units, the vapor line
grommet may be shipped as a loose part with the
14. Refer to the
Installation Manual
for the outdoor
unit and complete the leak check, evacuation, and
charging according to the instructions provided.
Check all field brazed joints and metering device
connections.
15. Attach the coil access panel to the cabinet.
16. Ensure that lines are sound isolated by using
appropriate hangers or strapping.
Figure 37: Vapor line grommet
Cleaning the coil
CAUTION
Ensure adequate precautions are taken to protect
electrical components and structure from liquid.
If the coil needs to be cleaned, clean the coil with water or
use Evap-Green by Nu-Calgon as an alternative to water.
Evap-Green is the only pH neutral coil cleaner approved
for use when correctly diluted.
Note:
Rinse coils thoroughly after use of Evap-Green
for cleaning.
Adjusting the air system
About this task:
You must check and adjust airflow as
required. Refer to the furnace or modular air handler
instructions for more information. To check the CFM,
you measure the static pressure drop across the coil
using a portable manometer and static pressure tips.
The entering and leaving air end of the XAF and XAH coils
have provisions for inserting a 1/4 tube for a pressure
measurement using a manometer. These access points
are for reference only. See Figure 38.
NOTICE
Table 8 to Table 11 have
dry coil
data. Run the
system indoor fan only for approximately 15 min
before taking measurements to assure a dry coil.
1. Prepare the coil for static pressure drop
measurements: ensure that the coil is dry.
2. With the indoor blower running at the appropriate
speed for equipment operation, insert the pressure
tips and capture the internal coil pressure drop.
3. See the relevant coil airflow data in Table 8 to
Table 13 to determine the airflow and make the
necessary adjustments to keep the CFM within the
airflow limitations of the coil.
4. After capturing airflow data and selecting the
correct blower speed, seal the holes appropriately
to prevent air leakage.
Installation Manual: XAF, XAH, and XAU Series - Full Cased and Uncased Coils for Cooling and Heat Pumps
29
Johnson Controls Ducted Systems
