Page 153 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

Chapter 2 Common processes and techniques

Commissioning

Commissioning is the part of the installation where the system is filled and
run for the first time. It is when we see if it works as designed. The first task is
to fill the system and check for leaks at the appliances. This is best carried out
in stages so that sections of the installation, i.e. cold water, hot water, central
heating, can be filled and tested separately. At each stage of the filling process,
the system should be checked for leaks before moving on to the next section.
Once the systems have been filled they should be drained down and flushed
through with clean water, then refilled. The water levels in WC cisterns, cold
water storage cisterns, and feed and expansion cisterns (if fitted) should be
checked for compliance with the relevant regulations.
Gas installations should be checked for tightness, and central heating systems
should be run up to full operating temperature before being drained down while
they are still hot. Refill the system and add inhibitor before running the system
again.

Check the flow rates at all taps to see if they deliver the flow rates demanded by
the manufacturer’s literature, and check the operation of all controls, including
thermostats and motorised valves. Set the temperature of any cylinder
thermostats and let the water reach full temperature. Using a thermometer,
check the temperature of all radiators and the temperature of the hot water.

Benchmarking KEY TERM
At this stage of the installation, it is time to benchmark the system. Here, the Benchmarking: this is now
boiler and any hot water cylinder installed are checked for compliance with the a compulsory requirement
manufacturer’s instructions, including: to ensure that systems and
appliances are installed
● hot water flow rates in accordance with the
● flow and return temperatures regulations and the
● hot water temperature manufacturer’s instructions.
● operation and types of control It also safeguards any
guarantee against bad
● gas rates. workmanship.

The benchmark certificate should then be signed by the commissioning engineer.

Building Regulations Compliance certificates
Since 1 April 2005, the Building Regulations have demanded that all installations
must be issued with a Building Regulations Compliance certificate. This is to
ensure that all Building Regulations relevant to the installation have been
followed and complied with. This includes:

● the heating installation
● the sanitation system
● the hot and cold water systems
● the gas installation
● any electrical controls.
Certificates are issued by Local Authority Building Control.

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