Question AC soft starts

[lostinfla]

I know a lot here have installed soft starts on their AC units to run both off a 30a feed. We are on 50a 98% of the time. My question:
Would I gain any benefits from this such as longer equipment life due to less voltage surge etc.?

 

[J&JD]

I know a lot here have installed soft starts on their AC units to run both off a 30a feed. We are on 50a 98% of the time. My question:
Would I gain any benefits from this such as longer equipment life due to less voltage surge etc.?

I’m also considering installing soft starts and would like to know the answer to @lostinfla ’s question. Is the mod really worth the money/effort?

 

[Richpatty]

It would also help prevent surges against the generator when running your AC from there….like driving down the road. I have it on 2 of my 3 ACs…. I think it’s worth it. And you never know when you would have to run from 30amp -or less- if plugged in at home.

My 2 cents.

 

[lostinfla]

Does it make any noticeable difference in the sound of the ac on startup?

 

[Richpatty]

I don’t think it is a huge difference…maybe a bit, but sometimes hard to notice over the fans.

 

[Richpatty]

It also allows me to run the front AC off battery/solar if I want (I did have to add special wiring for that).

 

[Old-RV'er]

Mike Sokol did an extensive review and test of the soft start system. You can find all the information on his website at link below. He has over 50 years experience. I wont use one, as I personally believe it places a fair amount of stress on an already stressed start/run capacitor system. I do not know if the practice to use one cap, to start compressor and fan is still being done. For me, I never use the auto selection on the fan, I select lo-med-high, so that every time the thermostat calls for the unit to start, it only starts the compressor, not both fan and compressor. Plus, keeping the air moving all the time, makes is so the units are not working as hard all the time.

Trust me, the A/C manufacturers are building the new unit as close to the marginal line as possible to keep their profits coming in, and with every day the EPA requires different coolant inside them, further stress on components which can fail. If we all get 10 years out of the a/c/heat pumps built today, I would be amazed . My a/c-heat pumps were working fine in my last coach at 11 years old, one reason is I never did it on auto fan, so I put the least amount of stress on those caps.

Voltage is very important especially to compressors. Never let voltage supply go below 107 Volts AC because that also stresses out the start run caps, plus stresses out the compressor. It's designed to run from around 112-123 Volts AC. If you don't have that voltage at incoming supply, run genset to use them if necessary.

For older motorhomes/trailers, if an a/c unit fails, and you have to replace with a newer unit, it's doubtful the controls will match up to what was installed at time of manufacturer. So, try to find a RV salvage yard, and buy a used unit as close to possible to what you have now, hooking up and getting it to work would not be brain surgery. Replacing a 10 year old unit with a new one, would be an integration nightmare with your existing thermostat, and wiring harness. Early units might have used a 4-6-8 wire harness from t-stat to A/C unit, today I have not got a clue what wiring harness is used, but new trying to match up with old won't work.

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