HP Performance Optimized Data Center (POD) 240a manual Adiabatic unit by unit blowdown

Adiabatic unit by unit blowdown

Before you begin the process below, be sure to complete the steps in "Supply header gravity drain (on page 76)."

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.

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.

3.Connect the air hose from the site or from a portable compressor to the open Y-strainer connection using 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.

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.

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.

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.

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.

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.

Maintenance 77