Thermo 90 S / Thermo 90 ST 6 Function tests
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6 Function tests
6.1 General
This section describes the tests conducted on the heater
and its settings when it is installed and not installed to
verify that it is in working order.
WARNING
The heater must not be operated in enclosed areas such
as garages and workshops without an emissions
extraction system.
6.2 Settings
6.2.1 Setting the CO
2
content
It is permitted for the factory-set combustion air quantity to
be modified. This is achieved by turning the air regulating
screw.
Setting procedure
Turning clockwise: CO
2
value is reduced (let the heater
run for about 5 minutes before measuring).
Rough setting: Screw the adjusting screw fully in
clockwise and then one turn back.
6.3 Testing individual components
6.3.1 Resistance test of the temperature sensor
If you conduct this electrical test with a digital multimeter,
the temperature sensor should have the following values
at room temperature:
Resistance at 25 °C: 990 ... 1010 Ω
Test current: < 1 mA
6.3.2 Resistance test of the glow plug
If you conduct this electrical test with a digital multimeter,
the glow plug should have the following values:
Glow plug: 12 volts (red) 24 volts
(green)
Resistance at 25 °C: 0.3 ... 0.6 Ω 1.3 ... 1.44 Ω
Test current: < 5 mA < 5 mA
6.3.3 Resistance test on the flame monitor
If you conduct this electrical test with a digital multimeter,
the flame monitor should have the following values:
Cold test:
Resistance at 25 °C: 3.0 ±0.4 Ω
Test current: < 5 mA
Hot test:
Resistance at 800 ±20 °C: 8 ±1.0 Ω
(ceramic rod at red heat over length of approx. 20 mm)
Test current: < 5 mA
6.3.4 Testing the combustion air fan
The motor speed test must be performed with the heater
assembled and in the operating voltage range. Listen out
for grinding noises.
NOTE
The cover must be removed from the fan in order to check
the motor speed. Fit a new seal before re-installing.
CAUTION
Make sure the detent lugs do not break off.
Fit a new cover and a new seal if the detent lugs have
broken off.
Speed in control range min. 1800 rpm (±9%)
Speed in control range max. 5600 rpm (±9%)
Fit a new combustion air fan if the speeds are outside
tolerance (see 9.2.5).
