Do You Think this is an internal or external box problem


Well-known member
This concerns an Spartan {brand} air conditioner soft start box that I bought in July with a 3 year warranty. It quit after about a month's use, and I opened tghe box and found an input wire burned at the circuit board screw terminal connection. My deduction is that an improperly tightened terminal screw caused the problem. The vendor is saying (without seeing any other wiring) that an external wire connection caused the burning at the terminal strip. , As you can see, there is no heat discoloration or melting of the incoming wire away from the terminal strip. The 2 sets of external wires show no signs of heat discoloration, either.
They are trying to deny my warranty claim .

What do you think?


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Past Ohio Chapter Leaders (Founding)
Totally looks internal to me. I agree with you that the fastener probably was not tightened (or stripped) properly.


Well-known member
I wouldn't be surprised if the solder joints under the screw down terminal were poorly done. The furnace heater control board on my RV did something similar, although, it wasn't apparent until I pulled the board to inspect it. Reflowed solder and all is good.

I would say that is a manufacturer issue if there is no other damage elsewhere.

Per federal law, they have to prove it wasn't their device that caused the failure in order to deny warranty. But I'm not a lawyer.

I installed 2 from SoftstartRV about 2 or 3 years ago and haven't had a problem, fortunately. But man are they expensive!

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Well-known member
Thanks, all.
Just got a phone call from the vendor company, Inverters-Are-Us (Reno, Nevada), CEO, saying he agreed it was an internal box issue, (he set his tech support guy straight) and I am getting a warranty replacement.


Well-known member
Good that they owned up. If an external connection were in fact the problem, as they tried to say, the entire wire would have been cooked. Not just the end at the terminal.
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Well-known member
I'm shipping the old unit out this morning.

My current plans are to keep the new AC soft start box on hand, and to only go up on the roof and install it IF there is a utility power shutoff in the area. The different brand previous soft start box I had wore out the main electrical contactor relay shortly after it went out of warranty (1 year) with very few uses during power outages with my generator. This Spartan brand box is installed by cutting 3 wires going into the compressor and simply splicing the box inline with those wires. When I took the defective Spartan box out of the Air Conditioner, I used Wago lever action connectors, so that re-connecting a new box should be a snap (pun not intended).


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Well-known member
Before I installed the soft start devices on my RV, I had two ATSs go out - first the original, then the new, upgraded version. After the second one went out, I investigated further and found that one leg coming into the house from the utility had low voltage. Oddly, the voltage was above 100V, which if I recall, is the minimum rated voltage that the ATS was designed for. The second ATS was replaced under warranty around a year after I installed it.

Realizing the ATS was too sensitive to voltage drops and the ACs running, rather than installing another ATS, I opted to install a mechanical transfer switch. I believe it was during this time that the power company started making plans to replace my service (no cost, part of a co-op), that I purchased the soft start units. I think the power company had already upgraded my service by the time I installed them. With no ATS in play, I didn't get to see how much the soft starts factored in while on shore power and turning the ACs on.

However, when on the generator, the ACs didn't affect the generator nearly as much as they did before I installed the soft starts.

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