3 Phase domestic system query

[EnerG]

Hello, hope you guys can shed some light on recent incident.

Recently I installed a heating system to a property in France that consists of a pellet boiler with vacuum feed, solar thermal, UFH etc... The system was all up and running nicely. A few months later , an electrician was working on the circuit board completing some work and he was alerted by another contractor that the room lights had dimmed and there was a noise from the boiler house and a burning smell. It was discovered that the circuit board for the vacuum and a heating controller had burned out. The manufacturer of the product advised that it was due to a power surge.
What could have caused the surge? The electricity supply is 3 phase, could this be the result if 2 of the phases had been accidentally linked to 1 circuit (i.e.) the circuit that the heating appliances were on?

Hope this all makes sense, thanks in advance.

 

[HandySparks]

Disconnecting the supply neutral wire without isolating the supply would be likely to lead to under- and/or over-voltage to any equipment still powered up.

 

[bill01803]

I had a board go on a pellet burner, afterwards I found out the vacuum should be wired through a relay.

 

[EnerG]

Disconnecting the supply neutral wire without isolating the supply would be likely to lead to under- and/or over-voltage to any equipment still powered up.

Thanks for your comments, I spoke to an electrician about this who said the exact same thing.

 

[EnerG]

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[EnerG]

I had a board go on a pellet burner, afterwards I found out the vacuum should be wired through a relay.

Hi, thanks for the comment. In this situation the vacuum is not connected to the boiler. It works independently.

 

[EnerG]

I have another question, since the circuit board of the vacuum has been replaced, both the boiler and the vacuum have been intermittently turning off without any human intervention. If the damage to the circuit board had been caused by the neutral having being disconnected/disturbed causing over-voltage on the phase - Could it also have caused any other damage or shorts on the phase.

Thanks again in advance, comments much appreciated.

 

[Dave the spark]

Disconnecting the supply neutral wire without isolating the supply would be likely to lead to under- and/or over-voltage to any equipment still powered up.

My first thought, or if it wasn't tightened properly at the terminal

 

[PEG]

Hi,has anyone deduced why the first fault occurred?

You need to know,as your second issue,could be a different symptom,of that existing fault.

I have worked on systems,like your own,where a series of breakdowns,have been attended to,by replacement of the individual components,without investigating any possibility of a cause,upstream.

This is sometimes due to the individual engineer being called in for one part of the system,and him/her,not having time/opportunity/permission,to look at the whole installation.

The addition of different installers for the various bits,and,i may add with a degree of experience,the French location...we have to add the L.U.T factor.

This is a unified and accepted practice,of replacing long and wordy explanations,with a gentle upward movement of both shoulders,simultaneously.