The purpose of this safe work method of statement or procedure is to define the step by step method to implement the correct practices for the precommissioning & commissioning of Close Control Units or CCU’s.
Through the guidelines contained herein so as to ensure that the job execution complies with the project requirements and serves the intended function to satisfactory level.
Precommissioning Procedure for Close Control Units CCU
Ensure that the unit installation is complete and mechanical completion is approved.
Ensure that no damage occurs between mechanical completion & precommissioning. Repair all damages to the equipment finish paint.
Check CCU is installed as per the approved shop drawings and manufacturer’s instructions. Check the level of the mounting frame is same as the raised floor level. Check the unit is properly fixed to the support. Check the CCUs are independent from the raised floor. Check the vibration isolator pads are installed.
Continue as per below steps:
- Check all chilled water piping, connected to CCU is with proper flexible connectors,valve package, drain, air vents, instruments, etc as per the approved shop drawing & manufacturer’s instructions.
- Check for the installation & insulation of condensate drain piping as per the approved shop drawings.
- Check for proper electrical power, control panel, BMS and earthing connections as per manufacturer’s recommendations. Field wiring to be pre-tested for continuity and insulation resistance.
- Check the interfacing with the fire alarm system & BMS.
- Check & record the voltage at the disconnect.
- Check & record the voltage at all control voltage transformers.
- Check all valves in the raised floor voids are accessible
- Check the U-trap in the condesate drain piping is provided.
- Check the piping connections to the units are done by using approved flexibles & as per manufacturer’s requirement.
- Check the identification is completed for the piping & the unit.
- Check sound attenuators are installed on the top of the units
- Check the water supply pipes are connected to the unit.
- Check that minimum distance from walls & full access for maintenance has been provided.
- Check that supply air from unit is not blocked by other services.
Commissioning Method for Close Control Unit
- Ensure that all the precommissioning checks are carried out successfully.
- Turn ON the main disconnect.
- Check the fan rotation is proper & free from any abnormal noise or vibration.
- Check main fan current & record in the performance test record sheet.
- Advance temperature set point to energise reheat, check reheat current & record.
- Advance humidity set point to energise humidifier, check the current & record.
- Adjust temperature set point to energise valve motor, check for full valve travel in cooling mode & for valve closure.
- Check high temperature alarm.
- Check low temperature alarm.
- Check high humidity alarm.
- Check low humidity alarm.
- Check loss of air flow (the static pressure measuring tube shall be removed & the signal for loss of air flow shall be proven)
- Check for proper functioning of humidifier ( the humidity set point shall be increased & the functioning of the humidifier shall be proven).
- Check leak detection alarm.
- Check smoke detection alarm (an NO/NC electrical signal shall be simulated and the smoke alarm shall be proven).
- Check & record ON/ OFF coil temperature & Air flow (cfm).
- Precommissioning check sheet for Close Control Units
- Commissioning check sheet for Close Control Units
- Performance Test Record for Close Control Units
- Risk Assesment
- Manufacturer’s instructions