Burco boiler tripping out power

[jpb]

Hi Folks,

I've got a 30l Burco bouler that I've been using for several years without issue, until recently. Firstly, a few weeks ago while using it to heat water for the mash the (4KW) voltage regulator failed with a pop and tripped out the mains.

So, VR replaced - this time with a 6KW one, I plugged in the boiler and the mains immediately tripped. As I hadn't even switched the power on at the socket I suspected a Neutral to Earth fault, so measured it and sure enough it was short circuit. After disconnecting and reconnecting the spade connector on the N side of the element it started working again, for a wile then the same happened again but also it tripped the mains when I turned the power down low, I repeated the test with the same result.

So, next up I replaced the element with a new one as it had a N - E short and I suspected that might be the cause of the tripping at low power - not that I can work out how that could happen. Once replaced I turned on the boiler again and all was OK until I turned it down low - then it tripped the mains again. I once again repeated this, slowly turning down the power and it seems the tripping point is about 10% power.

So, does anyone have any isea what could be causing this? Or any suggestions? I've checked the wiring and ensured it is wired as per the book https://www.burco.co.uk/sites/default/files/assets//WH00050-4 Burco Manual Fill Instruction Booklet (083184001 ISS 4).pdf with the exception that the 97° limit thermostat is bypassed and the thermostat is replaced by a voltage regulator. The neutral connections are via the COM connector on the VR.

This is the type of voltage regulator I'm using AC 220V 6KW SCR Voltage Regulator Motor Speed Controller Dimmer Thermostat | eBay

 

[Donegal john]

Could be your Tripp is on it’s way out and becoming more sensitive to the imbalance in the neutral caused by the regulator so the lower you go the more voltage there is going back through the neutral
How did you check your old element for a n-e fault ?

 

[jpb]

Could be your Tripp is on it’s way out and becoming more sensitive to the imbalance in the neutral caused by the regulator so the lower you go the more voltage there is going back through the neutral
How did you check your old element for a n-e fault ?

The consumer unit is only about 7 years old - so its unlikely to be that, and these problems have only started since the old VR blew. As for checking the element, it intermittently measured 0 ohms, with a digital multimeter - so I'm assuming there's an internal breakdown of the insulation, hence why I decided to replace it. What gets me though is why only at low power?

 

[Donegal john]

The consumer unit is only about 7 years old - so its unlikely to be that, and these problems have only started since the old VR blew. As for checking the element, it intermittently measured 0 ohms, with a digital multimeter - so I'm assuming there's an internal breakdown of the insulation, hence why I decided to replace it. What gets me though is why only at low power?

Age of board means nothing to be honest.
Every time a Tripp blows it weakens internally
when you say it measured 0 ohms where did you measure from ?
And at low power you are using a lot more resistance in the controller to limit the voltage flowing to the element hence a back feed / imbalance

 

[jpb]

Age of board means nothing to be honest.
Every time a Tripp blows it weakens internally
when you say it measured 0 ohms where did you measure from ?
And at low power you are using a lot more resistance in the controller to limit the voltage flowing to the element hence a back feed / imbalance

Firstly I measured it at the plug, then directly from the element terminal to the earthing point. At one point (it's intermittently faulty) I made the same measurement with nothing connected to the terminal.

The effect of the increased resistance causing a back feed / imbalance sounds a likely cause, and as I've changed to a different VR (the original blew) maybe this one just causes this more than the original did. I'm tempted to buy another 4KW one to see if it works better, if nothing else it would be a spare, and the last one lasted for 7½ years (about 70 brews).

And thanks for your help with this John.

 

[Donegal john]

Firstly I measured it at the plug, then directly from the element terminal to the earthing point. At one point (it's intermittently faulty) I made the same measurement with nothing connected to the terminal.

The effect of the increased resistance causing a back feed / imbalance sounds a likely cause, and as I've changed to a different VR (the original blew) maybe this one just causes this more than the original did. I'm tempted to buy another 4KW one to see if it works better, if nothing else it would be a spare, and the last one lasted for 7½ years (about 70 brews).

And thanks for your help with this John.

Or you could just keep it above the 10% that causes it to blow.
in my 33 years as a spark I have come across countless faults that have left me scratching my head. The last one was only last week.
A man I worked with a long time ago told me “ every days a school day “ and I’ve understood what he meant several times.

 

[jpb]

Update: In the end I bought another 4KW VR and sent the 6KW one back, I've now done a brew with the 4KW one and all was OK. I think the original issue was the element going faulty and shorting out the VR.