DIYbanter - View Single Post - Blew another damn transformer on my Trane XB80

Steve Turner[_3_]

On 4/9/2011 11:49 AM, wrote:
On Apr 9, 11:48 am, Steve
wrote:
On 4/9/2011 9:12 AM, wrote:

On Apr 8, 10:05 pm, wrote:
On 4/8/2011 8:44 PM, Tony Hwang wrote:

Steve Turner wrote:
A continuation of the "Why does the 115V-24V transformer keep blowing
on my Trane XB80?" discussion I started on 04/02/2011.

...

... Buy one of hevier one(bigger size and really heavier in
weight than stock) If it blows again, something on the load side is wrong.

I'd venture something is already wrong...

--

I'd agree. Responding to his first post and before he put this
latest transformer in I recommended measuring
how many amps are being drawn on the low voltage side.
This is electricity 101. So, he comes here asking for advice
and instead of listening, he justs puts another transformer in
and blows it too..... Go figure. Time to either get educated
or hire a pro.

In case you hadn't noticed, I've been getting LOTS of (much appreciated) advice
from many people, but it's also been very contradictory with no single
suggested approach. It's been an interesting and informative discussion, and
I've been happy that nobody's been a jerk about it... until *now*.

OK, so now I'm a jerk for suggesting that you should have taken some
basic
measurements, starting with the transformer output current, instead of
just
continuing to replace transformers and watch them blow.

I said no such thing. Your advice is perfectly sound, but your suggestions
were just some of many, and you seem to think I didn't follow *yours* (not
true), and yes you were kind of a jerk in the way you voiced it. It wasn't
really necessary, was it? You apparently don't have the patience to read
everything I wrote, otherwise you wouldn't claim that I'm just "replacing
transformers and watching them blow".

A component that supplies power fails by burning up. You've replaced
it
several times now. You think just MAYBE it's a good idea to see how
much power it's be asked to supply instead of just buyng new
transformers?

More evidence that you've chosen not to read everything that was written.

If a fuse blew out, would you just keep putting in new fuses

I'm not an idiot. Not completely, anyway.

or would you
measure the current and see what it is? I'd have measured the
voltages
and currents on both sides of the transformer after the first one
failed.

I know how to measure voltages (and I did; I mentioned that already) and
resistance to test for open circuits (continuity - See? I know some of the
terms. I even know the difference between A/C and D/C). But measuring and
understanding the ramifications of current (amperage) is where I get a little
fuzzy. Would you help me out? That's why I came here.

And I DID
listen; plenty of people suggested that the original transformer was likely to
be under-rated and to replace it with something more heavy-duty.

I find it hard to believe that Trane uses transformers in it's
furnaces that are
so under-rated that they burn out in a day. I also question the
soundness of
anyone telling you to start installing transformers capable of
delivering more
power without even taking some basic measurements and finding out
what's
drawing current and if it's excessive for some reason. If you had a
light
circuit that was blowing fuses, would your approach be to put in a
bigger fuse
or would it be to find out what's really going on? If you have a
short somewhere
and you put in a large enough transformer, you think you might
eventually heat
something up enough to start a fire, like maybe in the thermostat
wiring in
your walls?

I agree completely. I had my reservations about following such advice (and I
only went a *little* higher on the replacements; far less than what some
suggested), but I'm not an expert and many people were singing the same song:

"Discount the first failure, things simply get old and fail"
"The second failure could likely just be an inferior replacement part."

Clearly the third failure proves those two theories false. Live and learn.

Also, it
seems to me that having a working transformer is a pre-requisite to following
your advice of measuring the amp draw on the low voltage side, no?
Unfortunately, time constraints prevented me from being there to perform those
measurements when the unit was running, and unfortunately again the transformer
blew in my absence.

So, you had the time to obtain a new transformer, put it in, but
didn't have the
1 minute it would take to use a VOM to measure the current and voltage
on
the secondary? If it were me and I saw transformers burning up, I
wouldn't
leave it on until I had some confidence as to what was going on.

I already explained what happened. I'm sorry you feel the ongoing need to
point out the stupidity of my approach. It is what it is. Shrug

But of course, I'm repeating myself

Yes, by putting in each new transformer and watching it fail.

By golly, I think I'll do that again, it was such great fun.