PRE-COMMISSION CLEANING OF A PRE-FLUSHED SYSTEM
- Ensure that all low points and dead legs contain valved drain connections as large as is practically possible for full bore flushing.
- Fill system with mains water, vent re-circulate and check for leaks.
- Areas of low flow or restrictions (e.g. Staefer valves etc.) should be isolated or bypassed.
- Add GO-THERM CL28 via dosing pot (already installed) until product reserve of 1.0 – 2.0% minimum is achieved.
- Allow system to re-circulate with heat on (if possible) for a minimum period of 24 hours. Maintain a series of continuous checks to ensure that the treatment levels are within parameters (as in item 4 above) and no accumulations of debris is taking place within areas of flow. Take regular checks of iron levels, pH and electrical conductivity and tabulate over the cleaning period. When deposit plateau achieved with an excess of cleaning agent, proceed to stage (6).
- System to be dynamically flushed (i.e. drain from each outlet point with circulating pumps running, whilst maintaining constant supply of make up water). It is important to ensure that flushing velocities are maintained as near to 2.0 m/sec within all areas of the system. It may be necessary to isolate parts of the system temporarily to achieve these velocities or install auxiliary pumps.
- To monitor any sediment remaining within the system following the clean and to ensure the customer that steps have been taken to minimise any problems the following action will be taken:
On all systems where FCU’s are installed with flexible bypass couplings the following action will be taken:
A. On each floor layout, the last two units will be isolated on the LTHW and chilled water circuits.
This action would be taken wherever access is possible and in situations where the distributions pipe-work is not hard piped to the FCU’s. Where the units are installed with hard piping then any appropriate action such as flushing via drain off cocks should be applied. In cases where the above actions reveal problems the immediate notification to Business Manager or Chemical Cleaning co-ordinator must occur.
- Top up system and return to service and dose with the relevant water treatment corrosion inhibitor, i.e. GO-THERM CW25L.
- Check and clean all strainers and recheck all drain points for possible accumulations of light debris not removed by flushing process.
ON SITE REQUIREMENTS
In order to carry out the work Gower Environmental Services shall require the contractor to provide the following:
- All systems to be flushed and filled with fresh clean water at the commencement of work. We would emphasise the importance in removing excess jointing compound, e.g. Bosswhite and hemp as this type of deposit cannot be chemically removed.
- 220/240 or 110 volt single phase electrical supply within Plant Rooms and near the incoming mains terminal point.
- Adequate supply of fresh towns main water and connection to completely fill all systems simultaneously in 4 hours. To meet this requirement we would suggest that a 2 ins BSP minimum supply be available. The amount of water required during the whole process is approximately four time the systems capacities.
- Point for disposal of effluent to enable all systems to be drained simultaneously with all drain valves fully opened.
- All systems circulating pumps to be operational during the complete process. The success of our pre commission cleaning will depend on obtaining a minimum flow rate of 0.5 mt per second throughout every circuit.
- Minimum 1.5 ins BSP connections on flow and return pipe-work at lowest point in the system for injection of chemicals and draining down.
- At all other low areas which cannot be emptied from the main drains item to have