Well... that did not work as planned!

That is a classic symptom of a failed start device keeping the capacitor in the circuit for too long- not of a failed compressor.
I have never had to add a bleed resistor to a start capacitor- some have internal resistors, but all have had them installed.

From the linked page:

"Note: Not all manufacturers use start capacitors in their units."

But they ALL use a Compressor RUN Capacitor. Usually along with a Fan Run Cap as well. Those two are usually metal and may be in a common "can." 370 or 440 VAC and around 45-mfd for compressor, 5-mfd or so for fan. Which did you replace and have explode?

Start (assist) Cap should be around 100-mfd and usually plastic. If you get that in the form of a Kit, like SUPCO SPP6e recommended here, it'll be set up to do its job safely. If you buy an open stock capacitor, not knowing the application or how to wire it, I can see where you might have problems and those are above my pay grade.

But THIS I can say emphatically: IF the RUN Cap has failed, the compressor will sit in LRA (locked rotor amps meaning it can't turn) and that will trip the compressor's internal heat protection after a number of tries.

So, IMO, without seeing it and using a meter that'll read MFD, or swapping to BOTH new RUN and Start Cap's, measuring for LRA, I can still say your compressor may not be bad.

Did you replace the start relay?

"The potential relay should always be replaced when replacing the start capacitor."

Read this...

Malakie wrote:
Sorry I wrote in wrong area..

Problem appears to be the compressor... Start cap did blow due to way to much power draw from a frozen compressor.

Something else to pass along as well for those not knowing this..

When you buy a new start capacitor, exact model number etc, in some cases your unit REQUIRES a bleed down resistor to be soldered into the cap. You will know if you do if the bad cap you pull has a soldered in resistor between two posts.

Your NEW caps will NOT, repeat NOT come with that resistor. You MUST add one in this case. You can try to use the one on the old cap but I recommend you spend the 5 cents and use a new one to be safe.

One other note.. After all this, I tested out the old cap and the two I bought (one for replacing and an extra just in case). AS I said, the first new one installed smoked and blew through the safety release hole as designed.

But I tested it anyway.. The old cap showed it was shorted, as expected. The new untouched cap shows resistance of about 13.5 ohms.. Now get this.. the new cap that blew ALSO still shows 13.5 ohms.. which means it is still functional and did not burn out even with the smoke and pop.

HOWEVER, you do not want to use a cap even so that has done this. It has been compromised even if it tests good. In short order, it WILL completely fail AND most likely erupt into flame. So if you ever do this, regardless of what your meter shows, if a cap pops and smokes, toss it. DO NOT USE IT.

If you have a capacitor all alone that reads a constant resistance (like 13.5) it is shorted and no good.
Now if you have a resistor across it then your not measuring the cap.

Malakie. Gracias. You awakened a memory that had gone to sleep. Re the bleed down resistor. Many thanks.

Sorry I wrote in wrong area..

Problem appears to be the compressor... Start cap did blow due to way to much power draw from a frozen compressor.

Something else to pass along as well for those not knowing this..

When you buy a new start capacitor, exact model number etc, in some cases your unit REQUIRES a bleed down resistor to be soldered into the cap. You will know if you do if the bad cap you pull has a soldered in resistor between two posts.

Your NEW caps will NOT, repeat NOT come with that resistor. You MUST add one in this case. You can try to use the one on the old cap but I recommend you spend the 5 cents and use a new one to be safe.

One other note.. After all this, I tested out the old cap and the two I bought (one for replacing and an extra just in case). AS I said, the first new one installed smoked and blew through the safety release hole as designed.

But I tested it anyway.. The old cap showed it was shorted, as expected. The new untouched cap shows resistance of about 13.5 ohms.. Now get this.. the new cap that blew ALSO still shows 13.5 ohms.. which means it is still functional and did not burn out even with the smoke and pop.

HOWEVER, you do not want to use a cap even so that has done this. It has been compromised even if it tests good. In short order, it WILL completely fail AND most likely erupt into flame. So if you ever do this, regardless of what your meter shows, if a cap pops and smokes, toss it. DO NOT USE IT.

Moved from Forum Technical Support

lanerd wrote:
Cap??:h

Start capacitor.

Cap??:h

Malakie wrote:
I have a question.. Front AC compressor was not kicking in.. Thus either the start cap is bad or the compressor died. Went with a start cap to begin with for obvious reasons. Installed it. Turned the unit on and the cap blew up.

I know electronics but AC units are not my expertise... However I am assuming that installing the new cap and having it literally blow means the compressor is definitely toast ... (cap blew because WAY too much power was being pulled through it trying to start the compressor).

Is this a correct assumption? And if so, anyone know where I can get a salvaged, used, cheap replacement Coleman Mach III ac unit for my RV?

Thanks for any help..

You might get more help in a different forum. This one is for technical problems with the forum.