Hello new to the forum. I have a steam generator I'm trying to bring back to life. It connects to a 30 amp 240v power source. It keeps popping the 240v 2amp fuse when I turn it on. I see no swollen capacitors or burnt areas on the board. Where do I start?

 

Where the mains comes into the board, does it go to the transformer or straight to the relays, unplug the red wires to the transformer and see what happens.

 

Is your fuse fast-blow or anti-surge? The transformer inrush might blow a fast-blow fuse.

 

As Dodgydave says, disconnect the red wires to the transformer and see what happens – if the fuse does not operate, the likely fault is an overload/short circuit in one of the transformer output circuits.

I doubt that inrush current is blowing the fuse, a 2A fast-blow fuse can pass 3A for a considerable time. Don’t be tempted to increase the fuse rating, it might cause more damage.

If the fuse does not operate with the transformer unplugged, then test the circuit with each of the transformer secondaries connected in turn (green pair, yellow pair, blue pair) to determine which circuit has an overload/short circuit. There is no need to disconnect the black centre tap wire (associated with the blue pair).

 

Thank you everyone. I will try that this weekend. The fuse is fast blow. The mains go straight to the white switch.

 

Where the mains comes into the board, does it go to the transformer or straight to the relays, unplug the red wires to the transformer and see what happens.

I apologize again my lack of terminology. The mains go into the white breaker then the board. First black position at the lowest then the white being 3rd up from there. I believe they then hit the two red wires which go to the transformer. Your suggestion would be to unplug the red wires from the board power on unplugged and plugged? It only burns the fuse while the reds are connected.

 

the red wires are primary side of the transformer. make use to use time delay 2A fuse and have the red wires connected, but disconnect the plug with other wires (blue, yellow and green). this way you can see if the problem is transformer itself or circuit that it feeds.
if it still blows, even with time delay fuse and no load, transformer has internal short.
if it does not blow fuse any more, transformer is likely ok and you should be able to measure secondary voltage. check the circuit after for shorts (bridge or caps etc.)

 

the red wires are primary side of the transformer. make use to use time delay 2A fuse and have the red wires connected, but disconnect the plug with other wires (blue, yellow and green). this way you can see if the problem is transformer itself or circuit that it feeds.
if it still blows, even with time delay fuse and no load, transformer has internal short.
if it does not blow fuse any more, transformer is likely ok and you should be able to measure secondary voltage. check the circuit after for shorts (bridge or caps etc.)

The fuse only blows while it's connected with the red wires. So there's not really any way to check the secondaries then huh?

 

Okay. So swap the fast blow toca time delay and try again..?

 

The fuse only blows while it's connected with the red wires. So there's not really any way to check the secondaries then huh?

You can unplug the secondary side and see if it blows without a load to check the transformer outputs.

 

To be honest, if you have no clue about where you're problem is and its not going to mess up any sensitive electronics, putting in a bigger fuse to "smoke out" the problem might be an option. A last resort option, but an option. Just have a spare pair of shorts handy if its a good bang.
Other than that, Id start with disconnecting all the loads from the board, pumps, solenoids, sparkers and the like. Which I think is advice that's already been given.

 

Do you have multimeter? Are you able to use it?
Can you take more pictures from different sides?

right now all we know is that fuse on the primary side of the transformer gets blown.
But it is a wrong type fuse (need to be slow blow).
Also it is not certain if the fuse blows because of normal inrush current, because transformer has been damaged, or because somethings after transformer secondary is dead.

to find the problem among several candidates, you need to use process of elimination.
maybe everything else is fine and fast fuse just isn't able to cope with inrush current. replacing fuse would fix it.
maybe transformer is damaged but to confirm that, unplug secondary from the board. this way the only thing powered by red wires is the transformer itself....

 

Yes I'm able to use a multimeter. I will get some slow blow fuses so I can try again. I will take some more angle photos for you guys. I really appreciate the advice and patience.

 

Now that you know that it is the transformer causing the fuse to blow, follow my advice in the thread above, disconnecting the secondaries in turn, to determine which has the fault (causing the primary fuse to operate).

Once you find the faulty secondary circuit, further investigation will be required to identify the faulty component(s) causing the overload.

I doubt that the cause is not having a slow blow/time delay fuse fitted, a 2A (fast blow) fuse can pass 3A for a considerable time.

 

Yes I'm able to use a multimeter. I will get some slow blow fuses so I can try again. I will take some more angle photos for you guys. I really appreciate the advice and patience.

Now that you know that it is the transformer causing the fuse to blow, follow my advice in the thread above, disconnecting the secondaries in turn, to determine which has the fault (causing the primary fuse to operate).

Once you find the faulty secondary circuit, further investigation will be required to identify the faulty component(s) causing the overload.

I doubt that the cause is not having a slow blow/time delay fuse fitted, a 2A (fast blow) fuse can pass 3A for a considerable time.

 

So with the red wires connected and all secondaries disconnected the fuse blows immediately. Now this was my last fast blow, which I believe is what the system came with. I'll buy some time delay to further troubleshoot but. Thoughts? I also added a lame wire schematic

 

I would say that transformer is mounted upside down. When the bolt is tightened it will squash the connections between the lead out wires and the winding wire. Maybe there is a short circuit there.

 

So with the red wires connected and all secondaries disconnected the fuse blows immediately. Now this was my last fast blow, which I believe is what the system came with. I'll buy some time delay to further troubleshoot but. Thoughts? I also added a lame wire schematic

It's the transformer then, unbolt it and test with a multimeter.

 

The toroidal transformer appears correctly mounted (using a mounting kit) with damping material beneath the top securing plate. Having the connecting wires at the mounting surface is normal practice – I very much doubt over tightening of the securing bolt has squashed the wires, causing the issue, since the enclosure is made of plastic.

All the toroidal transformers I’ve seen are wound with the secondary wires wound above the primary wires on the toroid. Personally I think there is likely a short within the transformer (either in the primary winding or one of the secondary’s) – which will need replacing. Once you remove the transformer, there may be an indication of the damage location.

If you are lucky there will be a rating label on the transformer side wall listing the electrical ratings (input voltage, with each secondary output voltage and current rating) – if you are even luckier, you will find a replacement transformer having the required input voltage and secondaries.

 

The toroidal transformer appears correctly mounted (using a mounting kit) with damping material beneath the top securing plate. Having the connecting wires at the mounting surface is normal practice – I very much doubt over tightening of the securing bolt has squashed the wires, causing the issue, since the enclosure is made of plastic.

All the toroidal transformers I’ve seen are wound with the secondary wires wound above the primary wires on the toroid. Personally I think there is likely a short within the transformer (either in the primary winding or one of the secondary’s) – which will need replacing. Once you remove the transformer, there may be an indication of the damage location.

If you are lucky there will be a rating label on the transformer side wall listing the electrical ratings (input voltage, with each secondary output voltage and current rating) – if you are even luckier, you will find a replacement transformer having the required input voltage and secondaries.

It does have the rubber bushing under the large washer plate. I didn't see any visible issues.