Floor-standing Boiler

Domestic boilers have an output of between 9kW and 70kW
Many boilers have 'range-rated' burners - they can be adjusted to suit the size of the system

• Free-standing boilers were fitted in kitchens
• Cast iron heat exchanger
• Open flued
• Uses a permanent pilot as its source of main burner ignition
  • Piezo unit lights the pilot burner
• Multifunctional valve incorporates:
  • Constant pressure governor
  • Flame supervision device (thermocouple)
  • Solenoid valve
• Pilot assembly incorporates:
  • Pilot burner (injector)
  • Thermocouple
  • Spark electrode
• Boiler control thermostat electrically connected to the solenoid section of the multi-functional valve
  • Responses to water temperature fluctuations
    

Wall Mounted Boilers with Fanned Flue

• heat exchanger may contain as little as one litre of water 'low water-content' boilers require a positive flow of water at all times
• Pump overrun thermostat - to remove the residual heat from the heat exchanger
  
  

Natural Draught Open Flued Back Boiler

• Limited heat output - 15kW
• All pipework MUST be protected against corrosion from falling soot
• Atmosphere (vitiation) sensing device ASD must be fitted
  • Extinguishes the pilot and eliminates gas flow to the burner in case of incomplete combustion
  • Incorporates combined thermocouple/atmosphere sensing device
• Takes combustion air from teh space it is located
  • Lint arrestor - prevents lint from entering teh main burner
    

Combination Boilers

• Combination Boiler is an instantaneous water heater
• any hot water demand takes priority over the central-heating demand.

Condensing Boilers

• 94% efficient
• use the heat from flue gases 175-250°C by means of extra heat exchangers
• Flue gases - 75°C
• Condensate is a weak acid
• The flue system MUST always fall back
• BS 6798 - condensing pipe installation
  • MIN 22mm pipe
  • MIN 75mm seal
  • 50mm/m - MIN fall