Gas Safe Registration (ACS) Cookers, Laundry and Catering Appliances Syllabus

Cookers, Laundry and Catering Appliances syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Cookers, Laundry and Catering Appliances in Gas Safe Registration (ACS), not a summary of it.

1. 1

   Domestic Gas Cookers (CKR1)

   4 topics

   • Cooker types and installation
     • Freestanding, slide-in and built-in ovens/hobs
     • Stability brackets and anti-tip requirements
   • Connection methods
     • Bayonet fitting and flexible hose specification
     • Hose length, restraint and orientation
   • Ventilation and clearances for cookers
     • Room volume and openable window/extraction requirements
     • Clearance from combustible surfaces above hob
   • Commissioning burners, FSD and oven gas rate
2. 2

   Gas Tumble Dryers and Laundry (LAU1)

   3 topics

   • Gas tumble dryer operating principles
   • Flue/extraction and condensate requirements
   • Installation, ventilation and commissioning
3. 3

   Range Cookers and Combined Appliances

   3 topics

   • Range cooker gas rating and clearances
   • Multiple burner and oven safety devices
   • Extraction and ventilation for high-input appliances

Cookers, Laundry and Catering Appliances flashcards for Gas Safe Registration (ACS)

20 of 50 cards from the Cookers, Laundry and Catering Appliances deck — real questions with worked answers.

1. What does the abbreviation FSD stand for on a gas cooker, and what is its purpose?

   FSD = Flame Supervision Device. It detects whether a flame is present at the burner and automatically shuts off the gas supply to that burner if the flame is extinguished, preventing the escape of unburnt gas.

2. Describe how a thermoelectric (thermocouple-type) FSD holds the gas valve open.

   The flame heats a thermocouple, which generates a small EMF (typically around $20\text{--}30\,\text{mV}$). This current energises an electromagnet that holds the safety valve open. If the flame fails, the thermocouple cools, the EMF collapses and a spring closes the valve, cutting off the gas.

3. List the main installation classifications of domestic gas cookers.

   Freestanding (slide-in) cookers, slot-in cookers, built-in (separate oven and hob), and range cookers. Hobs and ovens may be installed independently or as a combined freestanding unit.

4. What is the difference between a freestanding cooker and a built-in cooker?

   A freestanding cooker is a single self-contained unit (hob and oven combined) that stands on the floor and can be moved out for servicing. A built-in installation has the hob and oven as separate units fitted into worktops/cabinets and fixed in position.

5. Define a range cooker.

   A large freestanding cooker, wider than a standard 600 mm appliance (often 900 mm–1100 mm+), typically with multiple hotplate burners and two or more oven cavities, giving a higher total gas input than a domestic cooker.

6. What connection methods are permitted for a freestanding domestic gas cooker?

   A flexible connection via a bayonet fitting with an approved flexible cooker hose (allowing the cooker to be pulled out), or a rigid pipe connection. The flexible hose method is preferred so the appliance can be moved for cleaning and servicing.

7. Why must a freestanding cooker connected by a flexible hose also have a stability device fitted?

   A restraining chain or stability bracket prevents the cooker tipping forward (e.g. when weight is placed on an open oven door) and stops the bayonet/hose being strained or pulled off. The chain must be slightly shorter than the hose so the hose is not stretched.

8. What is a bayonet fitting on a cooker connection?

   A self-sealing quick-connect coupling: a plug on the hose pushes and twists into a socket on the supply. The socket is self-sealing, so when the cooker is disconnected the gas is automatically shut off at the socket without needing a separate isolation valve.

9. How should a flexible bayonet cooker hose be orientated when fitted?

   The bayonet socket must be positioned so the hose hangs in a downward loop (inlet above outlet, hose forming a 'U' below). This prevents kinking, avoids the hose touching hot surfaces, and ensures any strain is taken correctly.

10. State the general formula for the gas rate of an appliance measured at the meter test dial.

    $$\text{Gas rate}\;(\text{m}^3/\text{h}) = \frac{3600 \times V}{t}$$ where $V$ is the volume of gas used in $\text{m}^3$ and $t$ is the time taken in seconds.

11. Give the formula linking gas rate to gross heat input for natural gas.

    $$\text{Heat input (kW)} = \frac{\text{Gas rate}\,(\text{m}^3/\text{h}) \times CV\,(\text{MJ/m}^3)}{3.6}$$ where $CV$ is the calorific value of the gas.

12. What gross calorific value is typically used for UK natural gas (G20) in gas-rating calculations?

    Approximately $38.7\,\text{MJ/m}^3$ (commonly taken as about $39\,\text{MJ/m}^3$, or around $1040\,\text{Btu/ft}^3$ in imperial).

13. How do you gas rate the oven burner of a cooker in isolation?

    Ensure all other burners/pilots are off, turn the oven to maximum (after any bypass/main rate is established), and time the meter test dial for a known volume of gas. Apply $\text{Gas rate}=\frac{3600 \times V}{t}$, then compare the calculated input with the manufacturer's data-plate figure.

14. When commissioning, how is correct oven performance verified after gas rating?

    Allow the oven to stabilise, then check the oven temperature with a thermometer against the thermostat setting (e.g. a Gas Mark / °C reference) and confirm the thermostat cycles the burner between full rate and bypass/off correctly.

15. What is the function of an oven thermostat with a bypass (low/simmer) rate?

    It modulates the oven burner: at temperature the gas is reduced to a small bypass rate (keeping the flame alight) rather than fully off, and reopens to full rate when the temperature drops, maintaining a stable oven temperature.

16. What ventilation provision is generally required for the room containing a domestic gas cooker?

    A domestic cooker normally relies on adventitious ventilation but the room must have an openable window or equivalent direct opening to outside air, and meet minimum room-volume requirements; a purpose-provided permanent air vent is not usually required for a cooker alone.

17. Why must a kitchen containing a flueless gas cooker have an openable window or door to outside?

    Because a flueless cooker discharges its products of combustion (including water vapour and any $\ce{CO2}$/$\ce{CO}$) directly into the room; an openable opening allows these products and excess heat/moisture to be removed when required.

18. What is the typical minimum vertical clearance required above the hotplate of a domestic gas hob to an overhead combustible surface or cooker hood?

    Per the manufacturer's instructions; a commonly applied minimum is around $650\,\text{mm}$ to combustible material and not less than $760\,\text{mm}$ (about $650\,\text{mm}$ minimum for a cooker hood) above the highest burner. Always follow the data plate/manufacturer figure.

19. What is the rule regarding combustible surfaces beside (to the sides of) a freestanding cooker hob?

    There must be no high-level combustible surfaces within the manufacturer's specified side clearance. A commonly applied guide is a minimum horizontal clearance to any combustible vertical surface above hotplate level (e.g. around $300\,\text{mm}$ unless the manufacturer states otherwise).

20. What does 'high-level combustible surface' mean in the context of cooker clearances?

    A combustible surface (such as a wall cupboard, curtain, or shelf) located above the level of the hotplate burners and close enough to be heated by flames/heat from the hob, posing a fire risk; minimum clearances must be maintained to such surfaces.

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