What would cause a new transformer to get smoked?
I bought a new transformer for my furnace that takes 120V down to 24V the Hertz matched that of the existing one, it worked great for about a week and then it tripped a breaker and literally smoked.

 

What would cause a new transformer to get smoked?
I bought a new transformer for my furnace that takes 120V down to 24V the Hertz matched that of the existing one, it worked great for about a week and then it tripped a breaker and literally smoked.

Short circuit somewhere.

 

VA rating the same?

 

Improper/inadequate fusing/protection.
Max.

 

VA rating the same?

Yes they are the same.

 

Improper/inadequate fusing/protection.
Max.

The transformer that I replaced was the original and had lasted approx. 5 years. I don't know what would have changed as far as fusing etc?

 

Short circuit somewhere.

I will check it out.
Thx

 

Short circuit somewhere.

I was just thinking about it; if it were a short circuit, could it have worked for a week before it tripped?

 

If you had to replace the original transformer, there must have been a fault that had developed with time. That fault would still have been present (unless you had since fixed it) when you put the new transformer in: hence the new transformer also failed. You need to locate the fault before replacing the replacement transformer .

 

Transformers almost never commit suicide. You must find the cause before you smoke the next transformer.
If you're a crafty type, you can add a fuse in the 24 volt wire to (maybe) save the transformer.
The last one I did like this, I had 3 fuses hanging on the red wire until the electronic air filter popped its fuse. Then I knew who killed the transformer.

 

I was just thinking about it; if it were a short circuit, could it have worked for a week before it tripped?

Post a picture of the board. We might be able to help you narrow down the issue.

 

Post a picture of the board. We might be able to help you narrow down the issue.

 

I will post a picture of the board.
So you suspect something in the board and not in the 120V powering the transformer?

 

So you suspect something in the board and not in the 120V powering the transformer?

Well you could blame the service Co. but highly unlikely!
The fact it tripped a breaker indicates you do not have any or at least inadequate fusing.
Max.