HP Performance Optimized Data Center (POD) 240a User Manual
Maintenance 77
Adiabatic unit by unit blowdown
Before you begin the process below, be sure to complete the steps in "Supply header gravity drain (on page
)."
These steps allow low pressure air to force water from the AHU supply header through an additional drain
that is located inside the access panel of each Adiabatic unit.
that is located inside the access panel of each Adiabatic unit.
1.
Remove the plug from the supply header debris Y-strainer.
2.
Open the flushing ball valve by rotating the handle 90º until it is aligned parallel to the strainer and
allow the Y-strainer to drain.
allow the Y-strainer to drain.
3.
Connect the air hose from the site or from a portable compressor to the open Y-strainer connection using
an air hose adapter.
an air hose adapter.
4.
Connect the air hose to the air source.
If you use a compressor, start the compressor and then open the air isolation valve from the chosen
source.
If you use a compressor, start the compressor and then open the air isolation valve from the chosen
source.
CAUTION:
Maximum allowable air pressure in the Adiabatic water supply header is 50 psi. Do
not exceed this pressure at any time.
5.
Move to the AHU service area of the POD.
6.
Shut down power to the Adiabatic unit that is farthest from the air source by rotating its power switch to
the Off position.
the Off position.
IMPORTANT:
Only blow down one Adiabatic unit per aisle at a single time. Failure to do this will
disrupt optimal air flow in the POD.
7.
Open or remove the media access cover to the left of the Adiabatic unit control panel that was just
turned off to show the inside of the unit.
8.
Locate the spray nozzle header assembly drain line.
9.
Attach the splash deflector finger-tight. Position the tubing so that blow down water is deflected into the
drain pan, which minimizes splashing.
drain pan, which minimizes splashing.
10.
Carefully open the spray nozzle header drain valve. Be sure to apply air pressure to the spray header
and observe that the splash deflector is in place.
and observe that the splash deflector is in place.
11.
Close the drain valve when either water stops flowing or air pressure is depleted.
12.
Repeat steps to open and close the drain valve until no water exits through the drain valve.
13.
Close the nozzle header drain valve.
14.
Locate and close the external Adiabatic unit spray nozzle header isolation ball valve to isolate the unit
from site water.
from site water.
IMPORTANT:
The external spray nozzle header may still be pressurized. This air pressure must
be relieved.
15.
Open the spray nozzle header drain valve to allow the header to de-pressurize.
16.
Close the spray nozzle header drain valve.
17.
Remove the splash deflector and replace or close the media access cover.
18.
Repeat steps to open and close the drain nozzle to complete blowing down the Adiabatic units on this
aisle.
aisle.