Page 467 - 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 7 Central heating systems

Solid fuel appliances

The most common types of solid fuel appliances are:

l open fires with a high-output back boiler
l room heaters
l cookers (Aga type)
l independent boilers.

Open fires with a high-output back boiler
High-output back boilers are installed behind a real open coal fire. These
appliances give their heat output in two forms:

1 radiation from the open fire for direct room heating
2 hot water from the boiler, which is available for domestic hot water supply
and central heating.

These appliances work on an open flue or chimney, and contain a manual
flue damper to regulate the amount of updraught through the chimney. By
regulating the updraught, a certain amount of control can be administered over
the heat of the fire. Typically, with the damper open, a fire of this type will give
around 6.8 kW to 10 kW of hot water heating output and, with the damper
closed, outputs vary from 5.3 kW to 8.4 kW. Radiated heat outputs from the p Figure 7.23 Solid fuel high-
coal fire directly into the room peak at around 2.6 kW. output back boiler

Room heaters
A solid fuel room heater is an enclosed appliance usually with a glass door so
that the fire can be viewed. They are installed directly into a chimney or open
flue capable of accepting solid fuel, and can either be stand alone or fitted
into chimney breasts with a high-output back boiler capable of serving up to
ten heat emitters. Room heaters provide radiant heat for direct warmth and a
constant circulation of convected heat.

Flue
Convected heat

Heating flow

Radiated heat
Water jacket

Heating return

Ash

p Figure 7.24 A room heater cut-away p Figure 7.25 A solid fuel room heater

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