Troubleshooting - Buderus Logano GA124 Installation And Maintenance Instructions Manual

Boiler inspection and maintenance

11.7 Troubleshooting

Equipment required: Wiring diagram page 81 and
voltage detectors for 120 VAC and 24 VAC.
Start
Close main gas valve.
Switch on power.
LED on aquastat on
continuously.
Adjust thermostat to heat
requirement (10 °F above room
temperature).
Adjust temperature control on
aquastat to heat requirement
(min. 10 °F above boiler
temperature).
Fan starts?
We reserve the right to make any changes due to technical modifications.
Installation and maintenance instructions Logano GA124 special gas-fired boiler • Issue 04/2005
• 120 V input voltage at N and L at connector X1?
If not: check power supply.
No
• 120 V input voltage at L1/L2 and L1X/L2X on aquastat?
If not: check wiring.
If the wiring is OK: replace aquastat.
• 24 V voltage at plugs C and R on aquastat?
If not: check wiring.
If the wiring is OK: replace transformer.
• Bridge thermostat contacts R and W.
If the boiler starts, check thermostat and thermostat wiring.
• Check LED on aquastat.
It flashes twice: check sensor contacts S2/S1 and sensor wiring.
If OK: replace sensor.
It flashes three or four times: internal fault, replace aquastat.
LED off: Aquastat in reset code, wait 5 minutes for automatic reset.
• 24 V voltage at plugs B2/B1 on aquastat.
No
If not: replace aquastat.
•
Check 24 V voltage at terminals 1 and 4 of the terminal on boiler block.
If not: check wiring between aquastat (plug B2 and B1) and terminal on
boiler block.
If there is voltage at terminals 1 and 4, check 120 V voltage at terminals
L3 and N on plug X3 for the fan.
If not: check wiring between relay and terminal on boiler block and relay
and plug X1 (input voltage).
If the wiring is OK: replace relay.
If there is voltage at L3 and N on plug X3, check wiring to fan motor.
If OK: replace fan.
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