Flushing HPU Prior to Taking a Fluid Sample

Reference ANSI B93.19M-1972, ISO 4021, and Tronair HPU Operation and Service Manual.

HPU With Single System

1. Connect pressure and return hoses together using a union or a Tronair Self Cleaning Circulation (“Run-

Around”) Kit.

2. Open return ball valve to maximum position (fully open)

3. Open the pressure ball valve to maximum position (fully open)

4. Open the bypass valve to maximum postion (fully open)

5. Reduce pressure control valve, located on pump, to minimum setting.

6. Start HPU and set flow rate to the maximum flow (increase pressure as needed to achieve max flow).

7. Fully close bypass valve.

8. Circulate fluid for 15 minutes

9. If fluid sampling is required, procede to Section 2.0. If fluid sampling is not required, procede to step

10. Open the bypass valve to maximum postion (fully open) and shut-down unit.

HPU With Dual System

1. Connect pressure and return hoses from system 1 together using a union or a Tronair Self Cleaning Circulation (“Run-Around”) Kit.

2. Connect pressure and return hoses from system 2 together using a union or a Tronair Self Cleaning Circulation (“Run-Around”) Kit.

3. Open return ball valves on systems 1 and 2 to maximum position (fully open).

4. Open the pressure valve on system 1 to maximum position (fully open)

5. Close the pressure valve on system 2 (fully closed)

6. Open the bypass valve to maximum postion (fully open)

7. Reduce pressure control valve, located on pump, to minimum setting.

8. Start HPU and set flow rate to the maximum flow (increase pressure as needed to achieve max flow).

9. Fully close bypass valve.

10. Circulate for 15 minutes

11. Open the pressure valve on system 2 to maximum position (fully open)

12. Close the pressure valve on system 1 (fully closed)

13. Circulate for 15 minutes

14. Open the pressure valve on system 1 to maximum position (fully open)

15. Circulate for 15 minutes

16. If fluid sampling is required, proceed to Section 2.0. If fluid sampling is not required, proceed to step 17

17. Open the bypass valve to maximum postion (fully open) and shut-down unit.

HPU With Triple System

1. Connect pressure and return hoses from system 1 together using a union or a Tronair Self Cleaning Circulation (“Run-Around”) Kit.

2. Connect pressure and return hoses from system 2 together using a union or a Tronair Self Cleaning Circulation (“Run-Around”) Kit.

3. Open return ball valves on systems 1, 2, and 3 to maximum position (fully open).

4. Open the pressure valve on system 1 to maximum position (fully open)

5. Close the pressure valve on system 2 (fully closed)

6. Close the pressure valve on system 3 (fully closed)

7. Open the bypass valve to maximum postion (fully open)

8. Reduce pressure control valve located on pump to minimum setting.

9. Start HPU and set flow rate to the maximum flow (increase pressure as needed to achieve max flow).

10. Fully close bypass valve.

11. Circulate for 15 minutes

12. Open the pressure valve on system 2 to maximum position (fully open)

13. Close the pressure valve on system 1 (fully closed)

14. Circulate for 15 minutes

15. Open the pressure valve on system 3 to maximum position (fully open)

16. Close the pressure valve on system 2 (fully closed)

17. Circulate for 15 minutes

18. If fluid sampling is required, proceed to Section 2.0. If fluid sampling is not required, proceed to step 19

19. Open the bypass valve to maximum postion (fully open) and shut-down unit.

Bottle Sampling Procedure

Reference ANSI B93.19M-1972, ISO 4021, and Tronair HPU Operation and Service Manual.

1. Reduce Flow rate to 1 gpm and pressure to minimum setting.

2. With a large bucket under the sample valve, carefully open sample valve fully allowing for a steady flow stream at the sample port.

3. Let the steady stream purge for 1 minute, no valves should be moved after steady stream purging begins.

4. Use only pre-cleaned sampling bottles, that meet ISO 3722, super-clean level, to take the fluid sample. Ensure cap and bottle are not exposed to contaminants.

5. With a steady stream flowing, open bottle lid and immediately fill bottle to 80% full level, remove the bottle from the steady flowing stream, and cap the bottle immediately. Repeat if more bottles are required.

6. Close sample valve.

7. Return HPU to normal operating condition.

Note: Fluid analysis should include particle count, fluid viscosity, TAN (Total Acid Number), water

content, wear metals and additive levels, and a photo analysis. Fluorine and Chlorine levels for

Aerospace applications should also be monitored.


Did this help answer your question?

thumbs up
thumbs down

Thanks for the feedback! 🙏🏽