Maximum and/or safety thermostat:
C
heck the condition of the sensor (no metal on metal contact with heat exchanger and that they
are central between the elements).
Flue gas fan.
Remove the inspection hatch. Check the bypass and fan restriction for soot and dust. Remove any
soot and dust with a brush. For restriction diameters, see [3].
V-belt pulleys for type G(N)CD.
Check the fan pulley(s) and belt tension, clean the pulley(s) if required. Check the belt tension
after 20 to 40 hours of operation. Regularly check the tension in the first year of operation [13].
After cleaning, put the appliance back into operation as described in section 3.3.
5.0 Description of parts
General
Faulty parts may only be replaced by identical parts. If in doubt, consult the manufacturer.
5.1 Automatic ignition control and gas combination units [6]
Argus burner controller, order code 06 15 085, in all appliances.
SIT Sigma 840 order code 0608050 in appliances 20, 22, 25, 27, 30, 35, 40, 45, 50 and 56.
SIT Nova 822 order code 0608057 in appliances 60, 65, 80, 90, and 95. Gas valves 06 08 025 +
06 07 090 are suitable for the Netherlands, Germany and Belgium and for types 90 and 95. [7]
B Adjusting screw pressure regulator
C Cable connections
D Pressure measuring nipple inlet pressure
5.2 Ionisation and ignition
[8]
Ionisation electrode order code 06 25 350
Ignition electrode order code 06 25 347
C Burner box
D Burner bar
5.3 Thermostat combination [9]
A One safety thermostat (STB), order code 31 01 655
A safety thermostat is a thermostat with a fixed setting, which is set higher than the maximum
temperature thermostat. If the maximum temperature thermostat fails, and the appliance over-
heats, this thermostat switches the appliance off. Once the cause of the failure has been rectified,
the thermostat can be released, after which the appliance will begin to operate automatically
(if heat is required at the time).
B One minimum temperature thermostat, order code 06 29 057
[14]
The sensor ensures that the fan(s) are switched on after a set warm-up time. The sensor also con-
trols post-operation purging to remove all the residual heat from the heat exchanger.
C/D One or two maximum temperature thermostats, order code 31 01 935
The maximum temperature thermostat switches the burner off when the value set is reached.
The fans continue to operate and the burner becomes operational (reciprocating motion) again
after cooling to below the value set. One or two thermostats may be installed depending on the
type of appliance. See the value-setting table for details [9].
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