barbas UNIVERSAL-6 70 Instructions For Use & Maintenance Manual page 19

UNIVERSAL-6 70
5.7 OUTPUT
In practice, combustion is all about loss.
This entails:
• Loss through excess heat leaving the chimney, rather than going into the room.
• Loss through insuffi cient combustion, such as CO (carbon monoxide) and soot
particles.
• Loss through excessive unburnt fuel in the ash.
The rate at which fuel can burn completely is called the output. A well-stoked appliance
achieves output of 75% and thus falls into the category of high-output / low emissions
appliances.
This means that you benefi t directly by using less wood to achieve the same level of heat.
The environment benefi ts as well: a well-stoked, high-output appliance means less
pollution and fewer odours.
Adverse effects on the output are:
• Burning the appliance with the door open.
A warm chimney works in the same way as an extractor. When the door is open,
the chimney draws in much more air than is necessary for combustion.
This relatively cool air cools down the appliance.
• Excessive chimney draught.
The combustion air does not reach the fuel, but leaves the appliance via the chimney.
The appliance cools and the combustion quality decreases.
• Using too much wood.
This is a problem if your appliance is too small. In that case, it becomes overloaded
and burns more wood than heat emitted. In this case too the fuel cannot burn
completely. More to the point, there is not enough air to mix with the fl ames. This has
an extra impact on the environment.
• Admitting too much air under the fuel (combustion air supply slider is than fully over
to the " + " position). Combustion is raised to high intensity (like a blacksmith's fi re).
Combustion really needs time. If combustion is too intense, there is insuffi cient time
for the fi re to radiate all the heat.
The chimney will become excessively hot and the same will be true of the escaping
smoke. This heat is thus lost.
5.8 CONVECTION FAN (OPTION)
If the appliance is fi tted with a convection fan, it will start working as soon as the
appliance has heated up suffi ciently.
Normally, this will be approximately 15 - 30 minutes after ignition. Hot air will then (as
preferred, refer to the installation instructions) fl ow into the room through the opening
above the door and/or through grills in the chimney.
Instructions for use 19