ALUTHERM
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Boilers 9
ALUTERM A 170 - 300
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Installation, user and service manual
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instructions for user
Heating
Alutherm A 170 - 300
In the case of failure or malfunction of the appliance, do not attempt to repair it yourself. Please contact your installer. Repairs must
only be carried out by qualified technicians. Failure to comply with these requirements can compromise the safety of the appliance.
4
OPERATION
4.1 General
The Alutherm A170-300 is a floor standing boiler, equipped with a cast aluminium heatexchanger. During heat demand the controller activates the
pump. The controller checks the air pressure switch (zero check) and increases the fan speed to perform an airflow-check. Once the air pressure
switch closes the fan speed increases to ignition speed and a 5 second pre-purge is performed. The water pressure sensor, gas pressure switch and
siphon pressure switch are checked. When all pressure switches are closed and the water pressure is ok, the ignition is started.
The air needed for combustion is taken in from the outside (if room sealed) or the boiler house (type B flue installation) by the fan. The air is transported
through a gas/air mixing device creating a negative pressure. This negative pressure is an indication of the amount of air being transported. The
negative pressure is supplied to the gas-valve by an internal tube. The gas valve automatically adjusts the amount of gas that will be injected into
the venturi and that will be mixed with the air-flow. This mixture is supplied to the burner.
Ignition and flame-control of the mixture is done by two electrodes mounted on the burner hood.
Temperature control and safeguarding is done using 2 NTC’s. The boiler monitors the sensors continuously in order to control operation and ensure
safe operation.
4.2
Central Heating (CH)
4.2.1
On-off room thermostat
As standard the boiler is programmed for using an on-off room thermostat. The room thermostat has to be connected to the pin nrs. 1 + 2 on the
terminal strip. Open Therm will be recognized if connected on 1 + 2. The desired flow temperature is adjustable, but as standard is set to 85 °C.
At CH heat request from the room thermostat (and no DHW heat request present) the CH-pump is activated after 10 seconds. The controller will
adjust the burner-input in such a way that a flow-temperature of 85 °C towards the CH-circuit is achieved.
Warning: do not supply any voltage to these terminals as you may damage the controller
4.2.2
Optional 0-10V
The boiler may be controlled using a 0-10 V DC signal. Connect the negative (0V DC) to No. 3, and the positive (0-10V DC) to No.4 on terminal strip C2.
A loop of wire must be placed between the pin nrs. 1 and 2 of terminal strip C2. In the technician menu, enable 0-10V in the advanced CH settings
menu by setting, CH request to either 0-10V DC % or 0-10V DC SP.
4.2.2.1
0-10V DC % power control
A value between 2 and 10V DC generates a CH power demand proportional to this value between 0 and 100% (0% = minimum load, 100% = nominal
load). The heat demand is removed when the control signal falls below 1 volt. The setpoint of maximum flow temperature is set to 90°C.
In the user/technician menu, under diagnostics, boiler information the actual voltage input and target power are displayed.
4.2.2.2
0-10V DC Setpoint
A value between 2 and 10V DC generates a CH setpoint demand proportional to this value between CH minimum flow temperature and maximum
CH flow temperature. The heat demand is removed when the control signal falls below 1 volt. The minimum and maximum CH flow temperature can
be set in the technician menu, advanced CH settings, CH temperatures.
Technician menu----> 1 advanced settings----> 2 CH temperatures----> 1 absolute max. temperature
Setting higher than 90 degrees is not allowed
In the user/technician menu, under diagnostics, boiler information the actual voltage input and boiler setpoint are displayed.
Caution: Ensure that the 0-10V DC signal is free from electrical interference!
