Schaerer Ambiente 2 Service Manual

Chapter 3 Functional descriptions
SMSO-2-02.03- 15.07.03 47
3.2.12 Safety thermostat
The safety thermostat is one of three safety levels used to
prevent an instant heater or steam generator from overheat-
ing, and thus bursting. If the control system does not switch off
the heater in normal circumstances, the safety thermostat will
disconnect the current once it reaches a temperature of 155
o
C. Overheating can be caused by a number of things (see
chapter on “Trouble shooting”).
Function
In principle, the safety thermostat is an electrical contact (N/C
contact) which is opened by a bi-metal disk when the switch-
ing temperature is reached. It is designed in such a way that
the contact is opened instantly (spring contact), thus prevent-
ing contact burning. The contact stays open until after the
instant heater or steam generator have cooled down. The
system does not automatically switch back on
It must be reset manually once it has cooled down, and this
should only occur once any faults have been rectified.
Reset: press the red button.
Safety thermostat
1 Instant heater
2 Klixon support (contact sleeve)
3 Thread bolt
4 Thermostat casing
5 Bi-metal disk
6 Opening contact
7 Spade terminals
8 Reset button
9 Thermo conducting paste
10 Contact open
The following conditions are crucial for reliable operation:
DANGER TO LIFE / MATERIAL DAMAGE
The safety thermostats can only fulfil their
function if they are correctly fitted and the
connections are not deformed. Incorrectly
fitted safety thermostats or thermostats
with deformed contacts will malfunction or
not function at all, and they will therefore
not switch off the electrical circuits. This
gives rise to the danger of the instant heater
or the steam generator bursting. When in-
stalling these items please note the follow-
ing:
 Heat conductance from the instant heater/steam
generator to the safety thermostat must be perfect.
All contact surfaces between the instant heater /
steam generator, contact sleeves and safety thermo-
stat, and also the safety thermostat threaded studs
must be coated with a sufficient quantity of thermo
conducting paste.
 The flat plug connections must not be bent either
during assembly, nor once installed, must they be
exposed to any mechanical stress whatsoever.
Contact sleeves
There are two different types of contact sleeves and they
differ in the shape of the support face on the instant heater or
the steam generator. They are identified on the exterior by one
or by two notches. One sleeve is used to fit the thermostat to a
round (spherical) surface (e.g. the instant heater), the other is
used to fit the thermostat to a cylindrical surface. In the Ambi-
ente-2 only contact sleeves numbered 061135 are used; slee-
ves numbered 061158 are used on the SE-2.
Technical data
Trigger temperature: 155°
Nominal voltage max: 250 V AC
Max. current: 16 A
max. tightening torque: 1Nm
Thermo conducting paste: part no. 067391
Check
It is not recommended that you carry out a heat test by heat-
ing up. Check that the unit is fitted correctly:
 is there sufficient thermo conducting paste at all contact
points?
 Are there signs of overheating (burn marks, or cracks
visible on the casing?
 Check the contact resistance with an ohmmeter (approx
0Ω !)
 Check the spade terminals for oxidation damage.
No further maintenance should be carried out on the safety
thermostat.
Drawing symbol Illustration

Schaerer Ambiente 2 Specifications

General

Brand	Schaerer
Model	Ambiente 2
Category	Coffee Maker
Language	English