Ariterm ARIMAX 700 Installation and operating instructions

INSTALLATION, OPERATION AND
MAINTENANCE
• ARIMAX 700-3000kW
Step grate boiler

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TABLE OF CONTENTS
System description ........................................................................ 4-6
Operating and maintenance procedures .........................................7
Safety systems guarding against burn-back ............................... 8-9
Maintenance ....................................................................................10
Technical specications ..................................................................11

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ARIMAX 700-3000kW Step grate central heating
boiler for wood chip heating

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SYSTEM DESCRIPTION
Ariterm bio-heating systems are designed for heating the boiler water of central heating sys-
tems. e system usually comprises a central heating boiler, fuel feed and burner, fuel stoker
and a control system with the necessary safety equipment. e Arimax step grate boiler is most
suited to the burning of high-quality wood chip.
Its operation is based on the temperature of the boiler water measured by the boiler sensor. e
burner is activated when the temperature falls below a certain limit value. Below this limit value,
the automatic control system handles the feed of fuel and combustion air so that operation is
as balanced as possible. e automatic control system thus aims to keep the boiler at a constant
temperature by increasing or reducing the power of the burner. If the heat requirement falls
below the level of the lowest thermal load, the control system switches to maintenance mode.
e heat requirement activates both feed augers, which transport the fuel to the burner. e
combustion air fans introduce combustion air into the combustion process. ere are separate
fans for primary, secondary and tertiary air.
Once the feed augers have emptied the intermediate tanks, the stoker auger is activated by
means of an optical level guard in an intermediate tank. e stoker auger rells the intermediate
tanks and stops. If the stoker auger runs for a pre-set lling time without fuel arriving at the
intermediate tank, a conveyor also starts up. e conveyor pushers transport additional fuel to
the stoker auger.
In the burner, the heat energy in the fuel is released as heat. Hot ue gases are cooled on their
way out of the boiler and the heat is transferred to the boiler water. e soot and ash emissions
of the boiler are reduced by means of a ue gas cleaner. e boiler operates on negative pressu-
re and so is equipped with a vacuum-controlled ue gas extractor. is extractor maintains a
balanced negative pressure in the rebox and ensures an even combustion process.
Note that the numbers of fuel augers, ash augers, combustion air fans and other ttings may
vary depending on the size of boiler and level of equipment selected.

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e control of the automation system is described in separate operating instructions.
e burner installed in such a boiler is of the solid step grate type. e grate consists of small
cast-iron blocks, which are arranged in steps. e primary combustion air comes from under
these blocks and is mixed with the fuel.
e secondary and tertiary air is controlled by its own fans at dierent stages of combustion.
e processes of connecting up and cleaning the boiler are described in separate instructions.
SYSTEM DESCRIPTION

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e Arimax step grate boiler is composed of the following parts:
• central heating boiler 700-300 kW 4-10 bar
• ash base
• step grate burner integrated into the ash base
• ceramic vault for the rebox
• combustion air fans (primary, secondary and tertiary)
• burner augers (2 pcs)
• grate shaker (optional)
• ash augers 1-2 pcs (optional)
e following may also be delivered with the boiler:
• ue gas cleaner (cyclone)
• vacuum-controlled ue gas extractor
• automatic sweeping of the convection section
SYSTEM DESCRIPTION

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OPERATING AND MAINTENANCE PROCEDURES
e Arimax step grate boiler is easy to use. e system’s automatic control directs the combusti-
on process by feeding in additional fuel and combustion air if required. e default values of the
automation system are set during the initial start-up.
Fuel
A step grate boiler is best suited to high-quality wood chip. Moisture level 20-40%, size of chip
approx. 40 x 40 mm. Fuel with a high proportion of ash and low melting point should be avoi-
ded. Contact your supplier if you intend to use mixed fuel.
Initial start-up
e mechanics and electronics of the system should be tested before lighting a re. Testing
should be carried out on all moving parts, motors, fans, burner automation system, safety equip-
ment and alarms.
• the operation and direction of rotation of the burner augers
• the operation and direction of rotation of the stoker auger
• the oil quantity in the hydraulic unit
• conveyor stoker operation
• the operation and direction of rotation of the combustion air fans
• the operation and direction of rotation of the ue gas extractor
• the operation and direction of rotation of the ash augers (optional)
• the operation of the grate shaker (optional)
Check the operation of the installed safety equipment!
Check the operation of the alarm chain!
Check that the boiler contains water and that the pumps are operating (operation and direction of
flow)!
Fuel stoker
Fill the fuel on top of the pushers. PLEASE NOTE! Remember to test the operation of the
conveyor before filling the stoker with fuel!

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SAFETY SYSTEMS GUARDING AGAINST BURN-BACK
1. Pulse-controlled burn-back protection. The system sprays water onto the fuel in the feed auger if
the temperature rises above a set value. It operates on the pulse-pause principle until the tempera-
ture has fallen. It neither stops the production of heat nor emits an alarm.
2. Burn-back thermostat. The automation system is equipped with a sensor. When it trips, the
protection system emits an alarm and turns off the equipment. The burner augers are run for 60
seconds so that the overheated fuel can be sent to the boiler.

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3. The AVTA valve lets water into the burner augers once a set value in the sensor has
been exceeded. The protection system is self-acting and even operates in cases of a
power cut. A large amount of water ows in and forms a water seal in the intermediate
tank between the re and the fuel stoker.
SAFETY SYSTEMS GUARDING AGAINST BURN-BACK

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SERVICING
e grate requires regular cleaning. e intervals between cleaning may vary greatly depending
on the fuel being used and the user prole. It is important that the air holes in the grate blocks
are kept open.
At regular intervals, check that the lower grate is not getting clogged with ash. e job of the
grate shaker is to move the ash from the grate to the ash auger.
Sweep and clean the boiler in accordance with the boiler instructions. A dirty boiler will lower
the eciency and increase fuel consumption considerably.
Spare parts
e step grate is located in the hottest part of the system and so is subject to heat stress. e life
expectancy of the cast-iron blocks can be greatly increased by keeping them clean.
e step grate consists of cast-iron blocks and the primary air channels are located in the lower
part of the blocks.

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TECHNICAL SPECIFICATIONS
Boiler Arimax Bio 700-3000kW 4-10 bar
Step grate Cast-iron elements
Combustion air fans Sodeca CMP-718-2T 0,75kW 4-6 kpl
Auger motors Flender CAD68-100L4 2,2kW 45rpm
Grate motor Motovario 0,55kW
TECHNICAL SPECIFICATIONS

10.03.2009 - All Rights to modifications and corrections reserved.
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39241 Kalmar | www.ariterm.se | 0771-442850