Dear All,
I require some advice in diagnosing a fault with a Vokera Linea 24.
When a demand for hot water is made AND the central heating has been on for some time (e.g. 1.5 hours or more), then the boiler gets stuck into a constant ‘on/off cycle’ that can only be cancelled by turning the boiler to off and letting it cool down. By ‘on/off cycle’ I mean flame-ignited/flame-extinguished. Approximately 2-3 seconds for each.
If the boiler is not given a chance to cool down and is switched back on and there is a demand (either water or heating) it will go straight into the ‘on/off cycle’ again.
When the boiler is hot, it sometimes seems to get locked into the ‘on/off cycle’ when there has been no demand for hot water. However, it could be that the flow switch has been momentarily triggered by a fluctuation in the mains water pressure, perhaps by the washing machine or dishwasher or the cold tap.
When the boiler is in the ‘on/off cycle’, it has been observed that the ignition of the gas alternates between a soft start and a more aggressive start. This may be of no consequence; I just thought I would mention it.
The pump and fan still run when the boiler is in this ‘on/off cycle’.
The boiler has never reverted to fault mode and locked-out.
The boiler seems to operate normally at all other times. I think it is reasonable to suggest that a high ambient temperature of the boiler and then a demand for hot water may be triggers to the problem.
So far:
-The domestic heat exchanger has been replaced. This was to address a previous problem of the water going hot and cold. This problem was successfully resolved.
-The system has been cleaned and flushed; though not Powerflushed.
-Both thermistors have been replaced. I.e. in the primary heat exchanger and the manifold (for the domestic heat exchanger).
-The fan has been cleaned.
Any solutions, or other tests recommended for further diagnosis would be most welcome.
Best Regards,
PMHN.
I require some advice in diagnosing a fault with a Vokera Linea 24.
When a demand for hot water is made AND the central heating has been on for some time (e.g. 1.5 hours or more), then the boiler gets stuck into a constant ‘on/off cycle’ that can only be cancelled by turning the boiler to off and letting it cool down. By ‘on/off cycle’ I mean flame-ignited/flame-extinguished. Approximately 2-3 seconds for each.
If the boiler is not given a chance to cool down and is switched back on and there is a demand (either water or heating) it will go straight into the ‘on/off cycle’ again.
When the boiler is hot, it sometimes seems to get locked into the ‘on/off cycle’ when there has been no demand for hot water. However, it could be that the flow switch has been momentarily triggered by a fluctuation in the mains water pressure, perhaps by the washing machine or dishwasher or the cold tap.
When the boiler is in the ‘on/off cycle’, it has been observed that the ignition of the gas alternates between a soft start and a more aggressive start. This may be of no consequence; I just thought I would mention it.
The pump and fan still run when the boiler is in this ‘on/off cycle’.
The boiler has never reverted to fault mode and locked-out.
The boiler seems to operate normally at all other times. I think it is reasonable to suggest that a high ambient temperature of the boiler and then a demand for hot water may be triggers to the problem.
So far:
-The domestic heat exchanger has been replaced. This was to address a previous problem of the water going hot and cold. This problem was successfully resolved.
-The system has been cleaned and flushed; though not Powerflushed.
-Both thermistors have been replaced. I.e. in the primary heat exchanger and the manifold (for the domestic heat exchanger).
-The fan has been cleaned.
Any solutions, or other tests recommended for further diagnosis would be most welcome.
Best Regards,
PMHN.