Page 496 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

The City & Guilds Textbook: Plumbing Book 1

Recommended minimum standards for control of existing heating systems
Replacement With hot water Gravity-fed systems upgraded to fully pumped
boiler cylinder Boiler interlock

Maintain existing space heating circuit(s), each with independent time control and a
room thermostat. TRVs strongly recommended
A hot water circuit with independent time control and a cylinder thermostat
No hot water Boiler interlock
cylinder (combi Maintain existing space heating circuit(s), each with independent time control and a
boiler) room thermostat. TRVs strongly recommended
One of:
l Flue gas heat recovery
l Weather compensation
l Load compensation
l Smart thermostat with automation and optimisation
New heating With hot water Gravity-fed systems upgraded to fully pumped
system with cylinder Boiler interlock
existing pipework
Maintain existing space heating circuit(s), each with independent time control, a room
thermostat and TRVs
A hot water circuit with independent time control and a cylinder thermostat
No hot water Boiler interlock
cylinder (combi Maintain existing space heating circuit(s), each with independent time control, a room
boiler) thermostat and TRVs
One of:
l Flue gas heat recovery
l Weather compensation
l Load compensation
l Smart thermostat with automation and optimisation
Radiator Emergency Good practice to fit a TRV to the replacement radiator(s) if in a room without a room
replacement thermostat
Planned Good practice to fit TRVs to all radiators in rooms without a room thermostat
Hot water Emergency A cylinder thermostat
cylinder Planned Boiler interlock

A hot water circuit with independent time control and a cylinder thermostat
Source: BEAMA (2018) Guidance on how to comply with Part L of the Building Regulations from April 2018

To comply with the requirements, the correct electrical controls must be fitted.

Time clocks and programmers

Time clocks are the simplest of all central heating timing devices. They are
suitable for switching on only one circuit, such as the heating circuit, and so are
ideally suited for combination boiler installations. Both mechanical and digital
time clocks are available.

Programmers are two-way time clocks, being able to switch on both heating
and hot water at various times throughout the day. There are three basic types:

1 A mini-programmer, which allows the heating and hot water circuits to be on
together, or hot water alone, but not heating alone. Ideally suited to C-plan
and C-plan plus systems.

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