4. 4. 3 Exchanging a defective heating
-
Separate the connections of the defective heater and if necessary from the dry-run protector
thermostat or the flat plugs on the PCB.
-
Remove defective heating element(s). It may be necessary to remove the perforated attachment
plate for the dry-run protector thermostat.
-
Remove remains of adhesive and silicone rubber with a knife, spatula or similar, or with petroleum
ether or diluent.
-
Degrease and prime the mounting surface of the tub.
-
Arrange the heating element(s) according to the wiring plan in appendix 3. The heating elements
should be placed on the flat sides as close to the tub bottom as possible.
-
Remove the protective foil from the heating element(s). Stick the heating elements to the tub and
avoid trapping air bubbles.
-
Press and roll the heating element(s) firmly onto the tub.
-
If necessary stick the perforated mounting plate (dry-run protector thermostat) onto the heater with
one-component cyanacrylate adhesive SICOMET.
-
In order to protect parts from becoming lose, apply silicon
rubber E 41 on the edges of the heating elements (5 mm
layer) and on the perforated mounting plate (completely
cover the bonded section of the plate). Do not completely paste
the edges of the heating elements, but leave 1 cm blank on the
long sides to avoid gas formation.
heating element
mounting plate
silicone rubber
leave blank
Example: Sticking one heating element with
silicone rubber
-
Allow the adhesive layers to cure for approx. 12 hours.
4. 4. 4 Exchanging the thermostat of dry-run protector
-
Desolder or pull off connections
heater
-
Unscrew the defective thermostat of
the dry-run protector.
-
Screw the new thermostat of the
dry-run protector onto the attachment
plate
Silicone
adhesive
layer
-
Solder connections back on.
attachment plate
tube
connections
thermostat of
dry-run protector
4. 4. 5 Checking the regulating thermostat
-
Remove knob. Older units are equipped with turning knobs incl. threaded bolt. Loosen it before
exchanging.
-
Unscrew both attachment screws and tilt thermostat towards inside.
-
Remove the plugged connections, do not bend the capillary tube!
-
Put the regulator knob back onto the axis and turn it clockwise to switch it on. There should be
conductivity between P 5 and 5 as well as P 6 and 6.
-
Keep turning the knob clockwise until you can hear a "click", at this point there should be conduc-
tivity between 1 and 2.
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