5 Heat Emitters & Panel Radiators

Heat Emitters

• Heat emitters transfer heat into a room or dwelling
• They come in a variety of styles and sizes
• Dimensions, outputs and styles are specified in manufacturer brochures

Panel Radiators

• Panel Radiators are a modern radiator commonly found in new builds
• Approximately 85% of the heat is convected via fins welded to the back of the radiator
• They warm the air creating convection currents
• Radiators without fins rely on radiated heat which can lead to cold spots
• Panel Radiators should be installed where flow is not obstructed
• Manufacturers suggest a minimum height of 150mm from the floor

Types of Panel Radiators

• Single Panel
• Single Panel with Single Convector Fins
• Double Panel
• Double Panel with Single Convector Fins
• Double Panel with Double Convector Fins

Panel Radiator Pipework Connections

• TBOE (Top-Bottom-Opposite Ends): This is the most efficient piping method but it can look unsightly
• BBOE (Bottom-Bottom-Opposite Ends): A common piping method, showing little pipework
• TBSE (Top-Bottom-Same End): A rarely used method, it is found only on one-pipe systems

Panel Radiator Dimensions

• Heights range from 300-900mm
• Lengths vary from 400mm, increasing by 100mm
• Common top types include:
  • Seam top: Commonly available with top and side grills
  • Compact: Common with factory fitted grills
  • Rolled top: Least popular; older design

Kickspace Heater

• Designed for rooms with limited wall space like kitchens, bathrooms and stairwells
• Installed under a kitchen or vanity unit
• Warm air flows in the room via a grill mounted on the kick plinth

Fan Convector

• These are similar to finned radiators, using a copper heat exchanger with many fins for additional surface area
• A low-volume electric fan is installed to operate when the heat exchanger warms up
• These emitters can heat large areas quickly

Skirting Convector

• Uses a finned copper heat exchanger but relies on natural convection
• Installed around a room replacing skirting boards and offering background heating
• A key disadvantage is that dust can block the fins and inhibit convection

Column Radiators

• These cast iron emitters have been used for many years
• More columns result in greater heat output
• They are also made from steel and aluminum
• They are used in public buildings and retro-fit properties

Low Surface Temperature Radiators

• Originally designed for the NHS, where surface temperatures must be below 43°C
• Commonly used in nurseries, primary schools, and homes for the elderly, disabled and infirm

Towel Rails

• Come in a wide range of designs and colors
• Can be used in a wet central heating system or independently with an electrical element
• Available in inverted radiator, conventional tubular, or designer styles

Underfloor Heating

• Works differently than conventional heat emitters, the floor becomes the heat emitter
• Pipework is laid under screed-in boards
• It is one of the most widely used systems for heating domestic and commercial properties
• It offers comfort, economy, flexibility and requires virtually no maintenance
• A minimum of 65°C is required at the manifold
• It is then blended from the return to approximately 55°C or 40°C from a ground source
• A boiler heats the system water, which is pumped to the manifold and distributed through circuits
• The pipe warms up the screed, floor, and then the room
• Characterized as having a lower and more even temperature
• The crucial factor is a slow flow rate to allow correct heat transfer
• The temperature difference is approximately 6°C
• The heat is concentrated at floor level

Advantages of Underfloor Heating

• Lower operating temperature
• Lower potential fuel costs
• Well-suited to ground-source heat pumps and solar systems
• Even heat distribution over the floor area
• No heat emitters on the wall

Disadvantages of Underfloor Heating

• High installation costs
• High component costs
• Longer time to heat a room
• Minimal or no condensation
• Not always suitable for every situation

Additional Considerations

• Heat emitters use convection and radiation to varying degrees, either natural or forced
• BS EN 442 specifies the standards for radiators and convectors
• Delta T is the temperature difference between the mean radiator temperature and the ambient room temperature

Plumber Installation Considerations

• Cost-effectiveness
• Customer comfort
• Control of the system
• Environmental issues
• Best practices (DHCG and CHESS)

Radiator Valves

• Valves fitted to each end of the heat emitter
• In the UK they are installed in the bottom female tapings of the radiator (BBOE)
• May be found fitted to top bottom ends (TBOE)

Wheelhead Valves

• Fitted to the radiator so the owner can turn it on and off
• They are closed with the lock shield valve to drain and remove a radiator

Lock Shield Valves

• Fitted to the radiator allowing the plumber or engineer to balance the system
• To remove the radiator, note the number of turns made to close the valve
• It is the same valve as the wheelhead, but the wheelhead is removed so that the owner cannot interfere with it

Thermostatic Radiator Valves (TRVs)

• These valves allow temperature control of a single radiator and are required under Building Regulations part L best practice
• TRVs have a special head that reacts to ambient air temperature
• A sensor contains a volatile liquid that expands when heated, closing the valve via a pin
• As the room cools, the liquid contracts, opening the valve
• One radiator in the circuit must be left without a TRV, according to Building Regulations, usually the hallway radiator
• A decorator's cap should be placed over the head if a TRV is removed for decorating
• A remote head can be installed if long curtains cover the TRV

Plumbing Tools

• A radiator valve key is required to secure the valve stems, no matter the valve type installed
• Four ½" BSP radiator inlets have two valves and a blanking plate, located in three inlets, and a bleed valve in one of the top inlets