3:4 The Lpg Boiler Starts And Switches Off; 3:5 Noisy Fan 20 6:4; 3:6 Noisy Burner; 3:7 Unstable Or Violent Ignition 21 6:5 - Alde Compact 3000 92X Service Manual

3:4 THE LPG BOILER STARTS AND SWITCHES
OFF AT SHORT INTERVALS
Cause:
- Voltage to boiler too low (< 12 V).
- Poor contact point in the wiring (earth fault).
- Pressure switch damaged or incorrectly connected.
- Ignition unstable.
- Flue blocked.
Action:
- Measure incoming voltage. It must be no lower than
10.8 V.
- Check the wiring connections, particularly the earth con-
nections.
- Check that both hoses between the pressure switch and
the fan housing are connected (see fig. 5).
- Replace the pressure switch.
- If the problem persists, please refer to "Unstable or vio-
lent ignition".
- Check that the exhaust cowl and the intake/exhaust
hoses are free from objects that may obstruct the air
supply.
3:5 NOISY FAN
Cause:
- The fan motor is damaged (worn).
- Impeller out of balance.
- Impeller touches fan housing.
Action:
- Remove the fan and check whether the impeller has
touched the fan housing (wear marks on the fan hou-
sing). If necessary adjust the fan housing axially.
- Replace the fan.
3:6 NOISY BURNER
Cause:
- Whistling sound from the burner on 92x-93x. Change to
burner 3000 516.
3:7 UNSTABLE OR VIOLENT IGNITION
Cause:
- The exhaust/intake hoses are too short.
- The exhaust/intake hoses are damaged or loose.
- The exhaust cowl is blocked.
- Incorrect gas pressure.
- Blocked or faulty soft start valve.
- Faulty nozzle.
- Low spark frequency.
- The pressure switch does not shut off or has stuck.
- The solenoid valves are leaky.
Action:
- Check that the intake/exhaust hoses are at least 2 metres
long and that they are undamaged and correctly fitted at
the boiler and flue (if a wall flue is fitted, 0.7-1.5 m).
- Check that the flue is free from objects that may obstruct
the air circulation.
- Check that the gas pressure to the boiler is correct
(28-50 mbar).
- Where the ignition is unstable, remove the soft start valve
and test-start the boiler. The start should now be stable,
but with a more violent ignition than normal. Replace with
a new soft start valve or clean the old one and carry out
another test-start.
- Unscrew the nozzle and check that it is marked "230".
- Detach the ignition cable from the electronic ignition unit
and start the boiler. A clicking sound should be heard
from the electronic ignition unit, with a frequency of
at least 2 Hz at 12 volts (two clicks per second). If the
frequency is too low the ignition electronics must be
replaced.
- Check that the ignition cable is intact and that there are
no short-circuits along the cable.
- Remove the burner and check that the spark electrode
is correctly fitted (see fig. 6) and undamaged. Replace/
adjust if necessary.
- Using a leakage tester, for example, check that no gas
is passing through the boiler when it is switched off. If
a leak is discovered, check that all gas connections are
tight. If there is no noticeable external leakage, replace
the solenoid valve.
3:8 OTHER TECHNICAL INFORMATION
• The electronic ignition unit may emit a slight high fre-
quency sound during operation.
• Boiler models 3000 92x and 3000 93x are intended only
for roof flues.
• Boiler model 3000 94x is intended only for wall flues.
• Boilers with manuf. no. 10921 and higher have circuit
board rev C, which means that the fan does not start if
the pressure switch is "on", and there is a new voltage
stabilisation which handles lower voltages (10 V).
• Boilers with manuf. no. 7536 and lower may have a fault
in the fan that causes a whistling sound.
• If there is a resonant noise on boiler model 3000 94x,
insulate the exhaust hose with insulation hose art. no.
1900 233.
• If the fuse (F2) has blown, the boiler should not be repai-
red but should be replaced with a new boiler.
• Insulate the outer pin on the solenoid valve so that it
cannot come into contact with the end plate. If this should
happen, the electronics box short-circuits and must be
replaced.
• In order to simplify operation and maintenance, fitting
automatic air bleeders on the installation can be
recommended.
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