Resistance Measurement For External Room Temperature Sensor; Servicing; General; Working On The Heater - Webasto Dual Top ST 6 Workshop Manual

7 | Servicing

6.3 Resistance measurement for
external room temperature sensor
Table 502: Technical data of external room temperature
sensor
Temperature [°C]
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
12,5
15
17,5
20
22,5
25
27,5
30
35
40
45
50
55
60
65
70
75
80
85
1 2
5
4
3
Fig. 7 Sensor positions
18 / 39
Resistance [kohms]
1,215 ± 0.5
844 ± 0.5
419 ± 0.5
299 ± 0.5
216 ± 0.5
156 ± 0.5
115 ± 0.5
84.5 ± 0.5
62.9 ± 0.5
47.1 ± 0.5
35.6 ± 0.5
27.1 ± 0.5
20.8 ± 0.5
18.5 ± 0.5
16.2 ± 0.5
14.5 ± 0.5
12.7 ± 0.5
11.4 ± 0.5
10 ± 0.5
9.0 ± 0.5
7.9 ± 0.5
6.3 ± 0.5
5.1 ± 0.5
4.1 ± 0.5
3.3 ± 0.5
2.7 ± 0.5
2.2 ± 0.5
1.9 ± 0.5
1.5 ± 0.5
1.3 ± 0.5
1.1 ± 0.5
0.9 ± 0.5
Pos. Description
1 Water temperature sensor:
Is only monitored by the control unit when hot water is
provided and for frost protection.
2 Water temperature switch:
Also interrupts the plus line of the fuel pump when
triggered
3 Air temperature switch:
Also interrupts the plus line of the fuel pump when
triggered
4 Air temperature sensor:
Is only monitored by the control unit in the winter mode
(heating with and without providing hot water)
5 Overheating protection (temperature switch of heat ex-
changer):
Is monitored by the control panel in every operating
mode.
Also interrupts the plus line of the fuel pump when
triggered.
7 Servicing
7.1

General

This section describes the allowed servicing work on the in-
stalled heater.
CAUTION
There is a potential danger of burns as the heater and
its components may be very hot.
7.2

Working on the heater

Disconnect the main power cable from the service battery be-
fore carrying out any work on the heater. You must not discon-
nect the battery power while the heater is operating or while it
is slowing down as a result of the risk of the heater overheating
and the overheating guard being tripped as a result. If you must
carry out extensive repair work on the heater, it is preferable to
remove the heater completely.
Refer to the relevant Installation Instructions for repairs that
make it necessary to change the installation position.
7.3

Working on vehicles

NOTE
A temperatre of 85 °C must not be exceeded in the vi-
cinity ot the heater in any cirumstances (for example
when competing painting work on the vehicle).
7.4

Heater test run

DANGER
Do not operate the heater in enclosed spaces (such as
garages) due to the risk of poisoning and asphyxiation.
7.5

CO2 setting

NOTE
After repairing the heater and replacing the fuel pump,
check the CO setting.
2
This also applies on replacement of the control unit.
The CO setting is carried out with Webasto Thermo Test PC
2
Diagnostics.
The heater is optimally set to a CO
eration at altitudes up to 2,200 m above sea level.
Continuous operation above 2,200 m above sea level can result
in heavy smoke and soot.
value at the factory for op-
2
9019782C WSH Dual Top ST