Schaerer Ambiente 2

Chapter 6 Control system diagram
216 SMSO-2-02.06- 15.07.03
6.5.28 Feed valve – “steam”
36V 5V DC

36V S L1, N
Operating condition
Once the water in the steam generator does not reach the level probe, the “steam” feed valve opens (closed at zero current).
Symptoms
The “steam” feed valve is not functioning.
Procedure
Process
step
Check Possible cause Remedy
1
Measure voltage at plug X37 1 on
power PCB:
36 V DC ?
 Check the voltage supply (see
“Power PCB, control voltage”)
 Voltage supply failure / faulty
2
Measure voltage at plug-in con-
tact stud (input) to feed valve:
36 V DC ?
 Plug contacts on power PCB
faulty / oxidised
 Cable broken or pulled out of plug
 Flat plug not correctly connected
 Check / replace plug contacts
 Replace cable
 Re-connect the flat plug on the
plug-in contact stud
Resistance measurement at feed valve:
 Switch off voltage
 Pull out cable from plug-in contact studs
3
Resistance measurement at feed
valve;
Nominal resistance:
60 Ω ?
 Plug in contact studs oxidised
 Faulty coil
 Replace feed valve
4
Voltage measurement X37 2,
GND
0 V DC ?
 Power transistor does not switch  Replace the power PCB
Reconnect the flat plug to the
feed valve.
Function check: The valve must
open (audible click!)
 Cable (gr) / power PCB faulty
 Mechanical fault on feed valve
(calcium deposit)
 Replace cable / power PCB
 Replace feed valve
NO
YES
YES
NO
NO
Y
ES
NO
Y
ES
NO