Webasto Thermo 90 Workshop Manual

Thermo 90 6 Functional Tests
601
6 Functional Tests
6.1 General
This section describes the on-vehicle and off-vehicle
testing of the heater to check its proper operation.
WARNING
The heater shall not be operated in enclosed areas like
ga
rages or workshops not provided with exhaust venting
facilities.
6.2 Adjustments
6.2.1 Adjustment of the CO
2
Contents
A change of the combustion air volume set by the
manufacturer may be performed by rotating the air set
screw.
Setting Procedure
Clockwise rotation: CO
2
value decreases (prior to
measurement; heater must have been in operation for at
least 5 min).
Coarse setting: Rotate air
set screw clockwise fully in
and then back one turn.
6.3 Components Testing
6.3.1 Temperature Sensor Resistance Check
During electrical testing of the temperature sensor using
a digital multimeter, the followin
g readings should be
obtained:
Resistance at 25° C: 990 ... 1010 Ω
Test current: < 1 mA
6.3.2 Glow Plug Resistance Test
During electrical testing of the glow plug using a digital
multimeter, the following readings should be obtained:
Glow plug: 12 Volt (red) 24 Volt (green)
Resistance at 25° C: 0.3 ... 0.6 Ω 1.3
... 1.44 Ω
Test current: < 5 mA < 5 mA
6.3.3 Flame Sensor Resistance Test
During electrical testing of the flame sensor using a digital
multimeter, the following readings should be obtained:
Cold test:
Resistance at 25° C: 2.6 ... 3.4 Ω
Test current: < 5 mA
Hot test:
Resistance at 800 – 1000° C: 12 ... 15 Ω
(ceramic rod red hot over a length of approx. 20 mm)
Test current: < 5 mA
6.3.4 Combustion Air Fan Test
The motor speed check must be performed with the
heater assembled and within the operating voltage range.
During the test check for grinding noises.
NOTE
For the motor speed check the fan cover must be
r
emoved. Prior to re-installation the gasket is to be
renewed.
CAUTION
Pay attention not to break off the lo
cking cams, otherwise
renew cover and gasket.
Speed in control range min. 1800 min
-1
(± 9%)
Speed in control range max. 6100 min
-1
(± 9%)
In case speed values are out of tolerance replace
comb
ustion air fan (see 9.2.5).
NOTE
On the Thermo 90 the function of the combustion air fan
can be
checked with the diagnostic computer or the
components tester.
On the Thermo 90 S the check is performed by means of
the PC heater d
iagnosis.

Webasto Thermo 90 Specifications

General

Brand	Webasto
Model	Thermo 90
Category	Water Heater
Language	English