SOP for Preventive Maintenance of AHU and TFA Unit EN-24

OBJECTIVE:

To lay down the Procedure for Preventive Maintenance of AHU and TFA Unit, air handling unit/ treated fresh air unit.

SCOPE: This SOP is applicable to Preventive Maintenance of AHU and TFA Unit installed.

RESPONSIBILITY: Technician/ Operator – Engineering shall be responsible for Preventive Maintenance of AHU and TFA Unit.

Engineering – Head shall be responsible for reviewing the SOP and for ensuring proper execution as per SOP.

ACCOUNTABILITY: Engineering – Head shall be accountable for proper implementation of the SOP of Preventive Maintenance of AHU and TFA Unit.

DEFINITIONS: Preventive Maintenance of AHU and TFA Unit refers to a systematic and planned approach aimed at ensuring the reliable and efficient operation of these HVAC (Heating, Ventilation, and Air Conditioning) components. This maintenance strategy involves scheduled inspections, cleaning, adjustments, and replacements of parts to proactively address potential issues, optimize performance, and extend the equipment’s lifespan.

PROCEDURE:

• Preventive maintenance shall be executed as per the SOP No.: SOP/EN/XXXYYY-Execution of Preventive Maintenance.
• Ensure that the spare parts shall be available at the time of preventive maintenance.

Precautions:

• Ensure that the equipment is in OFF condition and its mains supply has been switched off.
• Engineering department shall inform the User department (to which the AHU/ TFA caters) before starting the PM of the AHU/ TFA unit, so that the User department could take necessary action.

Frequency: 6 months ± 15 days

Check Points: Checking of  V-Belt:

• Check the V-belt (Wear, tear) physically.
• Check the Belt tension by using Belt Tension Tester. Ideal tension is the lowest tension at which the belt will not slip under peak load conditions.
• Belt Tension tester shall be operated as per SOP No. SOP/EN/XXXYYY
• If the desired value is not attained then replace the belt.

Other checkpoints in Preventive Maintenance of AHU and TFA Unit

•   Check the coupling, if available for any play and physical damage, if found then replace the same.
• Check the leakage from chilled water and hot water pipe fittings and valve. If observed replace the gasket and tighten the nut bolt.
• Check for any vibrations in the equipment during operation.
• Check the air leakages from AHU doors, dampers and duct joints if observed tighten nut bolts if required replace gaskets and apply silicon sealant.
• Check the functioning of control valves on utility lines and manual dampers on ducting.
• Check the blower & motor system for any abnormal sound, if observed correct by tightening the base bolts.
• Check the electrical terminal connection & earthing.
• Check the proper functioning of limit switch.
• Clean the surrounding area of AHU after performing maintenance.
• Clean chilled water and hot water strainer with wire brush and then with water.
• Clean chilled water/hot water coil surface by flushing water or use coil cleaner if required.
• Clean the drain with the sodium hypo chloride by soaking process for half an hour and drain the   line for controlling the microbial growth in the drain line.
• Check the IR value (current and resistance) of the motor, if the IR Value more than the set limit sends the motor for rewinding or change with spare. Record the IR value in preventive Maintenance Checklist & Record for AHU/TFA: SOP/EN/XXXYYY
• Check motor pulley and bearing for its proper functioning, if found any abnormality then rectify the same.
• Check chilled water hot water and duct insulation; if any damage is observed repair it.
• Half Yearly maintenance detail shall be recorded as per Format no. SOP/EN/XXXYYY
• In case of any modifications or major work is carried out to the equipment; the same shall be mentioned in the equipment history card as per the SOP no. SOP/EN/XXXYY.
• Connect the equipment main power supply and start the equipment.
• Ensure that the equipment is running smoothly, without any abnormality.
• Change the Preventive maintenance status label date on equipment display for done date & due date as per SOP/EN/XXXYYY

ABBREVIATIONS

• CRF No.   :     Change Request Form number
• QA            :     Quality Assurance
• PM            :     Preventive Maintenance
• TFA           :     Treated Fresh Air Unit
• AHU         :     Air Handling Unit

REFERENCES

• Nil  

DISTRIBUTION LIST

• SOP shall be distributed to the following departments Quality Assurance, Engineering as per user request.

ANNEXURES

• Preventive Maintenance Checklist & Record for AHU/TFA :   SOP/EN/XXXYYY

Preventive Maintenance of AHU and TFA Unit Checklist and Records

PREVENTIVE MAINTENANCE CHECKLIST & RECORD FOR AHU/ TFA

Things to be done: in Preventive Maintenance of AHU and TFA Unit	Check List	Remarks
Check the leakage from chilled water and hot water pipe fittings and valve. If observed replace the gasket and tighten the nut bolt.
Check for any vibrations in the equipment during operation.
Check the air leakages from AHU doors, dampers and duct joints if observed tighten nut bolts if required replace gaskets and apply silicon sealant.
Check the functioning of control valves on utility lines and manual dampers.
Check the blower & motor system for any abnormal sound, if observed correct by tightening the base bolts.
Check the electrical terminal connection & earthling.
Clean AHU pre filters and fine filter as per Filter cleaning SOP or replace with spare cleaned filters.
Check the V belt (wear, tear and tension) physically if required align properly.
Check the proper functioning of limit switch.
Clean the surrounding area of AHU after performing maintenance.
Clean chilled water and hot water strainer with wire brush and then with water.
Clean chilled water/hot water coil surface by flushing water or use coil cleaner if required.
Clean the drain with the sodium hypo chloride by soaking process for half an hour and drain the line for controlling the microbial growth in the drain line.
Check the IR value (current and resistance) of the motor, if the IR Value more than the set limit sends the motor for rewinding or change with spare. (Set value current _______ and resistance_________) (Observed value current _______ and resistance_________)
Check motor pulley and bearing replace or lubricate the bearing.
Check chilled water hot water and duct insulation; if any damage is observed repair it.

Mention √ or NA, whichever is applicable, under check-list.

Date of Scheduled PM	Actual PM done on	Next Due date	Done by	Checked by	Remarks

PM – Preventive Maintenance

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