Tuttnauer EA - Page 36

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the transistors should be vice versa: 0.0-1.0 DC. volt (on TP11) for Open
position.
e Check and replace the valve or the coil.
8 INLET KEY DOES NOT LET WATER INTO THE CHAMBER
e Check if this key is faulty. If it beeps when pressed it is O.K. if not
replace the keypad. If this does not help, replace the complete PREDG and
keypad unit.
e Check the float at the water reservoir by manipulating it using a screwdriver or a
tool, and repair/ replace it. If the float is functioning, the problem could be with the
control circuit at the PREDG board: the Test board between TP1 (GND) and TP10
(water valve): GOOD = 0.0V to 0.05V.
e Tt he control is OK, there may be a problem with the valve itself or with its connector.
e Check and replace the coil if necessary.
9 WATER VALVE IS ALWAYS ON AND THERE IS A CONTINUOUS FLOW OF
WATER INTO THE CHAMBER
Check the valve’s solenoid and the control circuit as you have checked the respective
exhaust valve and circutt (7.6, 7.7.). The valve could also be checked by depressing the
MANUAL water inlet key. If water flows in the chamber, or if there is
no flow of water once the system 1S initialized, the valve and its control are fine, but
the water level detector electrode may be damaged, or the connection between the
electrode and the circuit may be bad.
Check the wire and the connector connecting the electrode to the AJUNC3 board.
10 PRESSURE STAYS CLOSE TO 100 kPa (0 Psi), TEMPERATURE DOES NOT
EXCEED 110- 115°C (207°F) OR, WATER INLET LASTS A LONGER TIME THAN
USUAL
This phenomena is most likely due to malfunction of the air valve. The air valve’s
normal operation is as follows:
OPEN whilst turning the system on, OPEN throughout WATER INLET and HEAT
until temperature has reached 90°C or 194°F, CLOSED from that stage on, and OPEN
during DRY.
The valve’s control on the AJUNC3 board should act as follows:
0.0V = valve OPEN
5.0V = valve CLOSED
If the problem lies on the AJUNC 3 board it should be replaced. It is recommended to
replace both the AJUNC 3 and the solenoid because a damaged solenoid may affect the
AJUNC3 board. If the control circuit on the AJUNC3 is OK, the problem is probably
with the PREDG board.
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