22
9.5.2 Insucient output
The heat output of the air heater is insucient if there is
too much resistance in the inlet or outlet flue system. The
burner fan still rotates at full speed, but the resistance
prevents enough gas mixture from entering the burner.
• Check the flue system for blockage.
• Check the burner for dust or other pollution.
9.5.3 Non modulating system fan
System fan (M1) sometimes does not start or does not vary
in speed.
• Check the functioning of this fan by connecting it to
a supply of 230 V.
• Check if the fan is energised. Use a multi-meter.
If so, the cause of the problem lies in the burner
control unit.
10 Maintenance
CAUTION! The air heater must be inspected and
cleaned once a year by a qualified installer with sucient
knowledge about the device.
CAUTION! Sucient maintenance is critical in
circumstances such as high humidity, dust, high switching
on/o frequency, etc.
10.1 Preparation
Before performing maintenance on an air heater that is
already installed, do the following:
1. Set the thermostat to the lowest setting.
2. Close the manual gas valve.
3. Turn o the power supply to the air heater using the
maintenance switch.
CAUTION! Always check for gas leaks after working on
the air heater.
CAUTION! Do not use water when cleaning the air heater.
CAUTION! The heater must be electrically isolated during
servicing.
10.2 Basic maintenance
To perform basic maintenance on the air heater, do the
following:
CAUTION! When cleaning parts of the air heater, use
a dry cloth, brush, compressed air or a vacuum cleaner.
Never use a steel brush.
1. Inspect the outside of the heat exchanger.
2. Clean the fan guard on the outside of the heater.
Clean the fan blades if required.
3. Open the access panel.
4. Clean the inside of the air heater. Focus on the fol-
lowing parts:
– Body
– Fan blades and motor
– Heat exchanger
– Temperature sensor
– Vane switch (if present)
5. Check if the wiring, nuts and bolts are properly
secured and tightened.
6. Grease any parts and bolts that are regularly loos-
ened for maintenance.
7. Open the manual gas valve in the supply line and
check if the supply lines are air tight, do not leak
and do not contain air.
Some checks can only be performed when the heater is
running. Do the following:
1. Reconnect the air heater to the power supply.
2. Switch on the air heater.
3. Check if the heater operates without problems. See
chapter if any errors occur.
4. Check the air heater’s combustion eciency. If
necessary:
– Adjust the burner settings (see §7.1).
10.3 Maintenance of the burner unit
The burner unit is an important part of the air heater and
requires special maintenance.
To perform maintenance on the burner unit, do the
following:
1. Remove the gas pipe between the gas valve and
the combustion fan.
2. Remove the ignition and fan wires.
3. Unscrew the socket screws (M6).
4. Remove the burner unit from the air heater, com-
plete with flange and pre-mix fan.