Worcester Greenstar 15 ri blowing internal fuse

[markadams]

Hi,

Attended this yesterday, with the internal fuse blowing as soon as it is switched on. I disconnected ALL the current draws from the PCB and still the fuse blows so it must either be the transformer or the PCB.

As the transformer is available as a plug in item I was hoping some one can tell me the expected resistances I should expect from a working unit so I can test the current one.

 

[kb76]

Can't remember without looking up. WB technical might still be there Saturday afternoon who should be able to help

 

[cdodds2004]

how old Is the boiler? I would probally just go for the pcb as it was updated a few years ago and isn't badly priced anyway

 

[mfgs]

It will be the transformer. Had this a couple of times on the Ri.

 

[mfgs]

I cant remember the resistance readings for it, but there is a strip between the plugs on the back of it. This will look damaged and cracked, it will also smell like electrical burning.

 

[Tonycane]

As above, transformer. Took me ages to find it first time, I unplugged everything fan etc and it was still blowing, then noticed transformer was abit difformed

 

[markadams]

Went back armed with a PCB and transformer, after removing the old transformer I found the overside had melted and scorced the PCB so both were replaced and all is now good.

 

[Last Plumber]

The primary will be 240v I don't know what the secondary is but let's say it's 24v
The two sides should be 10 x different so for example, if one side was 1.2 ohms the other side would be roughly 12.0 ohms, ( roughly).
If they're similar or OL . It's failed