A simple convector stove
The FHT Stove is a type of convector stove. Convector stoves provide comfortable radiant heat (like the sun)
from the glass front and warmed air from the top of the stove to circulate in the room.
To achieve convective heating, the firebox of the stove is surrounded by an ‘air-gap’ formed
with the outer surfaces of the stove where air is heated and naturally rises to leave from holes at the top
of the stove.
Radiant heat provides the ‘warm glow’ sensation as it heats objects that it encounters
as it radiates from the stove, including people. However, it does not provide much heat to the air.
Convective heat warms the air giving an all-round comfort.
Exploded view, principal
components; heat exchanger and fan
The FHT Stove adds to the simple convector stove by incorporating a low-power, low-noise fan
in the base of the stove which can reverse natural convection over the outer
surfaces of the firebox in the air-gap.
When the fan is ‘on’ warm air that would
normally come out of the top of the stove is directed to a heat exchanger under the firebox.
The heat exchanger takes heat from the hot air into the water of the central heating circuit.
When the fan is ‘off’ heat comes out of the top of the stove as normal.
Around half of the stove heat can be diverted to the central heating system - instantaneously!
No combustion gasses pass through the heat exchanger or enter the room.
The diagram to the right shows the FHT Stove components under the firebox of a convector stove.
In the ‘on’ view it shows how air from the top and sides of the stove is drawn
downwards through the heat exchanger by the fan.
The exploded view shows the three principal
components that are required to turn an ordinary convector stove into an FHT Stove, these being
the fin-tube heat exchanger (similar to a small car radiator), a cross-flow fan and a cowl
which connects the heat exchanger and fan to each other.
In the ‘off’ view below, warm air leaves the top of the stove by natural convection.
The room air enters the air-gap at the bottom of the stove having been drawn through the fan (‘off’)
and heat exchanger. The fan and heat exchanger are designed for very low pressure loss to ensure they
do not impede the air flow due to natural convection.