Water Distiller Keeps Shorting

[Jonathan Adams]

Hi Folks,

Ive got an elderly water distiller that packed in a few weeks ago, with a suspected blown heating element (kept tripping the main fuse).
Sent away for new parts, installed them and now it just blows the local fuse, accompanied by a flash and a bang.
Ive been over it all with a multimeter and can't for the life of me figure out what I'm doing wrong.
I've replaced the thermal reset switch as well.
Attached is a pic showing the connections - I'd really appreciate any advice or suggestions.
Many thanks

 

[westward10]

As suggested above you need to do a plan of the wiring and components if you don't have one and progressively test parts of it but this is going to be difficult without test equipment you cannot keep plugging it in to see if the fuse holds.

 

[Ian1981]

I was thinking that in #24 but didn't dare say it

Ha you chicken

 

[westward10]

I know nothing of the internal wiring but red with black seems like a no no and the op has messed about with it.
It might be a before pic I don’t know

I thought the same but there seems to be several black lives on the micro switches.

 

[Ian1981]

I thought the same but there seems to be several black lives on the micro switches.

Just doesn’t look right does it?

 

[Jonathan Adams]

None of the wiring has been altered since I bought it. The only time its been undone is to replace components, which I've done several times over the years, without any problems. Red to black? Agreed damned strange, but its Canadian originally - maybe that's a thing?..

 

[Des 56]

Jonathon,best not to operate the equipment until the fault is sorted,you may end up roasting the switches etc if they are dead shorting
I suggest you try and firstly get hold of a wiring diagram, use your meter to trace the circuit connections to be sure they are as they should be

 

[Jonathan Adams]

Jonathon,best not to operate the equipment until the fault is sorted,you may end up roasting the switches etc if they are dead shorting
I suggest you try and firstly get hold of a wiring diagram, use your meter to trace the circuit connections to be sure they are as they should be

I'm awaiting an up-to-date wiring diagram from the manufacturers, but so far some sort of short on the live seems the most likely explanation - just have to find it! And no. -I have non intention of trying to use it 'til its fixed

 

[Pete999]

I thought this was a place for advice rather than admonishments, Pete...

 

[freddo]

I thought the same but there seems to be several black lives on the micro switches.

They might be neutrals, it's common for appliances to have switches in the neutral.

 

[Deleted member 9648]

None of the wiring has been altered since I bought it. The only time its been undone is to replace components, which I've done several times over the years, without any problems. Red to black? Agreed damned strange, but its Canadian originally - maybe that's a thing?..

Before you got involved it was tripping the RCD, this would be an earth fault most likely an element which you have replaced. Now it is blowing the fuse, not the RCD. This would suggest two possibilities.
1. The original fault remains but the RCD is now Knackered.
2. There is no longer an earth fault but a dead short L-N, that would suggest the element that you have replaced was causing the earth fault but the replacement has been wrongly connected.

 

[Lucien Nunes]

Yes, if you are now immediately tripping the MCB with a bang you probably have a hard short from L to N that you created either by
a) damaging a cable (unlikely, would probably cause earth fault in which case RCD would tend to trip too / instead)
b) making an incorrect connection during reassembly
c) fitting a new part with an internal short (only applies to parts with both L & N present

So get out your meter, put it on 200 ohms across the plug pins and satisfy yourself the short is there. Then start opening circuits - turn off the switches, operate the float microswitches, to see which if any disconnect the short. If none, then start disconnecting likely contenders - e.g. what happens if you disconnect the output leads from the thermal cutout?

Hang on, are you sure that thermal cutout is correctly connected? I don't know the specific unit but looking at its shape, I would sort of expect 1 & 2 to be L and N in, and 3 & 4 to be L & N out, so that one pole of the switch is each side of the fixing screws. You've got it rotated through 90° relative to that, so that 2 & 4 are the input. If that is incorrect, and I am truly not sure, then it will short the L & N together and trip the MCB (and the rest of the unit will be immaterial as it won't even be connected to the mains). You can soon check this with the meter, or look it up if you know the part number. This is just a hunch... don't go by hunches use your meter!

 

[freddo]

don't know the specific unit but looking at its shape, I would sort of expect 1 & 2 to be L and N in, and 3 & 4 to be L & N out,

On these stats it's 1&3 are the supply, 2&4 are the load. Here is a diagram of the limit stat (attached to a control stat):

 

[Lucien Nunes]

Ah thanks Freddo, so OP ignore my comment about this possibly being the fault, it was only a (wrong) hunch.

 

[w0z]

Worrying for the safety of the OP that he may not know how to trace a basic short. My guess is that the connections of the new element were assumed incorrectly to be the same as the original and what would be a common (assume neutral although labelled L2 in diagram above) connection has been transposed to one of the lives, or it’s just been connected wrongly.
It seems unlikely the new element would be faulty, but easily checked. As said, meter on low ohms range across L-N in, repeat with switched in other positions, then disconnect the element and repeat. It would help to know the wattage of the elements to give you a guide of what resistance to expect, but around 30 ohms would be approx 2kW, compared to less than a few ohms which would be a bang.
Don’t continue unless you know what you’re doing!