Actuator - Bosch SRU53E05AU Repair Instructions

4.2

Actuator

1 PTC
2 Contact
3 Pressure spring
4 Wax-filled cylinder
815_58300000120057_ara_en_d.doc – 25.05.11
5 Contact
6 Plunger
X Plunger travel
The thermohydraulic system consists of a metal cylinder with plunger.
The cylinder is filled with a substance which expands greatly when
heated. The heat source is a PTC (positive temperature coefficient)
(1) which is in direct contact with the metal cylinder (4). A strong
pressure spring (3) returns the plunger (6) back to its original position
when the heat source is switched off.
When voltage is applied to the PTC (1), the PTC heats up and
transfers the heat to the wax-filled metal cylinder (4). The wax
expands and forces the plunger (6) out of the cylinder. The plunger (6)
transfers the mechanical movement to the release mechanism for
dispensing the detergent and rinse-aid. If the heat source is switched
off, the volume of wax is reduced by the cooling process. The
pressure spring (3) returns the plunger (6) back to its original position.
Technical specifications:
Designation
Nominal voltage
Frequency
Resistor
Actuation time
Reset time
Value Unit
110–240 V
50 / 60 Hz
0.5–1.5
kΩ
approx. 2 min.
approx. 3 min.
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