[Michale32086]

I had a LOT of great help from here getting my daughter's Goodman unit up and running..

Details and pics are here:

http://www.diychatroom.com/f17/central-air-unit-just-quit-355898/

Now it appears a NEW problem has developed...

The unit comes on and blows hot air and everything is fine for 10 mins or so. Then the HEAT breaker pops...

The unit still is on and blows air but it's cold air.

It's a 60AMP breaker...

Not sure what the problem could be....

Any hints/tips/suggestions would be most greatly appreciated...

 

[beenthere]

Could be 1 of the strip heaters has blown and is shorting out against the frame. Ohm them out with the power off of course.

 

[Michale32086]

Not knocking your expertise by ANY stretch of the imagination...

But if it was a short, wouldn't the breaker pop immediately??

I am going to pull the cover off this morning and see what I see...

I'll follow-up later this morning..

 

[beenthere]

Not knocking your expertise by ANY stretch of the imagination...

But if it was a short, wouldn't the breaker pop immediately??

I am going to pull the cover off this morning and see what I see...

I'll follow-up later this morning..

Good question/thought.

Average 5KW rated element has around 10 ohms of resistance. If it blows, and one side shorts to ground, and that section only has 4 ohms to ground. 120 volts divided by 4 ohms, that is an amp draw of 30 amps. Combined with the other elements amp draw(24 amps or so), it can be just low enough not to trip the breaker right a way. But enough for the breaker to trip after the heat has been on for several minutes.

 

[Michale32086]

OK, kewl.. I assume if there is a short, it would be noticeable.. Black char/residue on the frame of the unit, etc etc...

I'll know more once I get the cover off... I have a new smartphone so I can actually post from the unit itself and get more timely data.. Daughter doesn't have internet yet...

 

[beenthere]

If an element shorts t ground. You can't see it from the control panel side.

If your unit has 2-5KW strips, they should both be drawing about teh same amperage.

When I suspect a blown/shorted element, I check the amp draw on each wire feeding each element. A large difference means 1 is shorting.

 

[zappa]

One other thought to consider. Breakers trip both on over current or too much heat (delayed). Loose or corroded connections to the breaker on either the load or line side can make them heat up too much and trip.

Also, worn or abused breakers can generate internal heat and need to be replaced if they are tripping below their rating.

 

[Michale32086]

Okay I'm here at the unit and I've got the heat elements pulled out there doesn't seem to be any obvious shorts. I turned on the unit while the element was out and the element started to heat up. But I'm kind of worried about letting it run because it's kind of sitting precariously on the ground.

Here is a picture of the component side of the element board.

That's where I'm at right now.

 

[Bob Sanders]

I wouldn't run the element without air. There is a chance you could burn it up. These elements are not meant to be run without air movement around them. What you need to do is use a clamp ammeter to measure the amperage draw while it is in (proper) operation. You may not be actually pulling 60 amps and all is okay... which means you're dealing with a weak breaker that needs replacing..... (and that would be my guess. I just replaced a 100 amp breaker which was popping at less than 1/2 that)

If you don't have a clamp ammeter... you can get them for MUCH cheaper than a furnace guy... and they're easy to use.

 

[Michale32086]

Here is what I have for a meter.

I let the unit run for about 8 minutes before the breaker tripped. That is with the element installed in the unit. After that I tried to put them reset the breaker and it would not reset for a few seconds and then it finally did. After I did that the unit only ran for three or four minutes before the breaker tripped. While it was running I made sure that I was looking at the components side of the heat element, hoping to see a spark or a short when the breaker tripped. I did not see anything like that at all. Which has me believing or hoping that it's a bad breaker. Forgive the run on sentence and formatting this is my first time posting from a smartphone.

 

[Michale32086]

Here is a picture of the breaker.

 

[roughneck]

Don't run that heat strip pulled like that, it'll be damaged.
Use a meter for troubleshooting. If you don't have one then you'll need to go buy one.
I see signs of moisture on that heater. All that rust needs to be cleaned off the terminals

 

[Michale32086]

Think I "fixed" it.. I took the breaker panel off so I could look at the breaker to see if it was corroded or anything. 4 sheets and greens I decided to start the unit up just to see. It's been running for about 15 minutes with no problem. That seems to indicate to me that the breaker needs replaced.

 

[roughneck]

What's the amp draw on the circuit? Are any connections loose or getting hot?

 

[Michale32086]

What's the amp draw on the circuit? Are any connections loose or getting hot?

How would I check that??

 

[roughneck]

Your meter......

 

[kb3ca]

Replace the breaker. They're not that expensive.

 

[Bob Sanders]

Here is what I have for a meter.

That's a clamp Ammeter. Open the clamp and place it around ONE of the red cables coming off the breaker. Start up your heat turn the ammeter setting to the clamp reader selection and measure the amperage. If it's less than 60 you have a weak breaker, breaker not seated right, or corrosion where the breaker connects to the panel. If it's more than 60 then you have a problem with the furnace.

 

[Michale32086]

Just wanted to follow up and say that replacing the breaker fixed the problem...

Now, I can do an official WOOT!!!

Just wanted to say thanx again to everyone.. Saved me a ton of money..