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airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8048
Experience:  Furnace, A/C and heat pump specialist.
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Why is my Goodman furnace tripping the circuit breaker?

Resolved Question:

My Goodman heating unit trips the breaker outside at the panel. I have had the breaker replaced. It is a 60 amp breaker. It does not trip this one unit. The model is ARUF036-00A-1. What can cause this. It only trips it after the heating temp. has been on for a few cycles. I had the amps checked at the unit and it was 18.5. The unit is rated at 18.8. This has been an on going problem.

Submitted: 5 years ago.
Category: HVAC
Expert:  airheatman replied 5 years ago.

airheatman :

Is your breaker tripping that feeds the indoor unit or the outdoor unit?

The ARUF is the indoor unit. Do you have a heat pump or straight electric heat? Is the breaker that is tripping supplying power to the indoor unit, the outdoor unit or both?

Customer :

It supplies to the indoor unit. It is a straight electric heat.

airheatman :

Ok

How many KW of heat do you have

There should be a label on the front of the ARIF air handler that states how many heat strips are installed

Customer :

I don't recall the KW amount, but each set of elements are rated at 18.8 amps and the max operating amp is 20/20. Can you determine the KW with the model? The unit also has a part number on it 14310-04

airheatman :

When the unit comes from the factory, it does not have any heat strips. The installer installs either 5KW, 10KW or 15KW heat kit. The original label from factory showing amp draw does not include heat strips.

Customer :

There are three

airheatman :

The model number you listed shows no heat (thus the 36-00).

If you have three elements, you have 15 KW heat

This is why breaker is tripping

Customer :

Yes you are correct

airheatman :

Technically a 5 kw strip can draw as much as 22 amps

airheatman :

So 3 five KW strips will draw as much as 66 amps plus whatever the blower draws

Customer :

There is a 60 amp breaker in the inside unit, but it does not trip.

airheatman :

Can you tell me where the third strip gets its power ? Normally if you have 15 KW you will have both a 60 amp breaker feeding 2 strips as well as a 30 amp breaker feeding the third element. Do you not have the second breaker at the air handler?

Customer :

If the unit is drawing too many amps. shouldn't the inside break trip also? Because it feeds from the supply box.

airheatman :

Do you not have 2 breakers on the air handler

Customer :

Yes, there is a 30 amp, and a 60 amp

Expert:  airheatman replied 5 years ago.

Do you have two different power sources feeding the two breakers or just the one that is coming from the 60 amp in main panel?

If both the 60 amp breaker and the 30 amp breaker are fed from one 60 in the main panel, the one in main panel will trip when that third element which is fed by the 30 amp breaker comes on.

If your furnace is being fed by one 60 amp breaker, when the third element comes on, it is drawing more than 60 amps. In the unit, everything is protected because only 2 elements are on the 60, but when the other element comes on, it is drawing on the same breaker in main panel. You will need a separate 30 amp breaker in the main panel supplying voltage to the 30 amp in air handler or a larger wire and breaker to feed both the 30 and 60.

Does this make sense to you? You have a 60 amp circuit from your main breaker panel feeding a 60 amp breaker in the air handler. This is fine and will not cause any problems. However, when you connect the third heat strip ,on the additional 30 amp breaker with the 60 amp circuit, you are overloading the circuit and therefore tripping the breaker. To prevent the circuit from overloading, you will need to add a separate 30 amp circuit to the air handler to feed the 30 amp breaker and third element. Or you would need to replace the 60 amp breaker to a 90 amp breaker and replace the 60 amp wire with 90 amp wire.

Let me know if you have a separate 30 amp breaker in the main panel that supplies power to the 30 amp breaker in the air handler. If not, you can turn the 30 amp breaker off and just use 10 KW heat until you can have wiring corrected.

Customer: replied 5 years ago.

My unit has both a 60 and 30 amp breaker in the air handler as well as a 60 and 30 amp breaker in the main panel. The 60 amp outside is the one that trips.

Expert:  airheatman replied 5 years ago.

Ok, so you do already have two separate breakers feeding the air handler. That is good. Next let us look at the 60 amp that is tripping. What size wire do they have ran between the main panel and air handler? It should be at least #6 copper. We can go from there.

Customer: replied 5 years ago.

It is AWG #6, and AWG # 8 at the 30 amp

Expert:  airheatman replied 5 years ago.

Are there any connections or junction boxes between the breaker and air handler that might have a loose wire connection?

Customer: replied 5 years ago.

None

Expert:  airheatman replied 5 years ago.

Do you have an amp meter to verify that all elements work? I would say you could have an element in the air handler that could be shorting to trip the breaker. I do not believe that two elements are drawing enough amps to trip it. But I am like you, I would think the breaker on front of air handler would trip. It really sounds like your breaker itself is getting hot. Have you looked at the buss bars where the breaker plugs into the main panel to verify the breaker bus bar is making a good connection?

Customer: replied 5 years ago.

Yes, I just replaced the 60 amp. It is a FPE type. It is snapped into the bus tight. I do see some overheated ends on two of the element wires that is connected to the sequencer. I put my meter on them. They are drawing and average of 17 amps. on the two strips. The third is not on.

Expert:  airheatman replied 5 years ago.

This definitely sounds like a loose connection overheating rather than over amps. I just cannot tell you why the one in the air handler doesn't trip. The only thing I can think is that the big breakers in the Goodman unit are not true rated breakers, but rather disconnects.

Customer: replied 5 years ago.

I will replace the connectors on the wires and contact you again if it continues, but thanks for your help.

Expert:  airheatman replied 5 years ago.

Thanks for letting me work with you. Feel free to follow up and I would like to know what you find.

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