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Topic: Installing Soft Starts on your air conditioners (Read 666 times) previous topic - next topic

Installing Soft Starts on your air conditioners

We ordered 3 Soft Starts for our Dometic Penguin 1 airs and they came in last week..  Finally, yesterday, decided to head up on the top and start the process.  All 3 of ours are also heat pumps, which really doesn't make a difference in the wiring diagram.  We ordered these on RVillage and received  $150 off for the 3 which kept the bill under $800.  Normally, these are $299 each, so made the decision to order for this price.
The instructions are okay, but on some things, you are better off just to remove the wire from the start capacitor and be done with it.  From the time I went up and started on all 3 and a call to tech support, since our start capacitor did not have any markings on it, we spent approximately 6 hours total with the install.  In the photos below, you will see the maze of wires and a burned up PTRC which, from what I have understood, assists in the starting of the compressor.  I found this burned out item at the bottom of the control panel box when I went to remove it.  You do not need this item when installing the soft start, since theirs is built in.  I will also have to say that there tech line is very helpful and patient with all the questions.  A nice touch.  I also learned that there is little difference in the wiring of a Duo Therm and a Penguin ! or 2.  This is a job, that if I can do it, you can as well.  It gives you the ability to run 2 airs on 30amp service with microwave purring in the background.  A nice feature since many RV parks are only 30 amp.
One other thing I did notice, it does not quiet down the initial startup of the unit when it comes on.  Was hoping for this, but eventually, we will start replacing our Dometics with either new ones or consider the Furrion units that have rave reviews.  I hope this helps others that are considering this upgrade.  Yes, the motor is rusty and there was some dust inside, but after all , these units are 20 years old and most likely ready for a long overdue upgrade.  Ugh, more money!

Re: Installing Soft Starts on your air conditioners

Reply #1 –
Very nice. That should help the generator start as well.

Re: Installing Soft Starts on your air conditioners

Reply #3 –
Quote from: Chuck & Jeannie –
It is recommended best practice around this Forum to turn OFF all 110V loads (like air conditioners) BEFORE starting generator.


ABSOLUTELY!

Same for plugging into shore power.

No load when switching saves the points of the ATS.

Re: Installing Soft Starts on your air conditioners

Reply #4 –
Question? If the ats defaults to generator and you are driving the coach and start the generator do you still need to shut off the roof A/C's? Kind of a nuisance to do while driving and you want to add roof air to cool.

Re: Installing Soft Starts on your air conditioners

Reply #5 –
Quote from: craneman –
Question? If the ats defaults to generator and you are driving the coach and start the generator do you still need to shut off the roof A/C's? Kind of a nuisance to do while driving and you want to add roof air to cool.

Really depends on your individual set up.  If your air conditioners have a DELAY before starting, no need to shut them off.  But, if they start the instant the ATS delay is over and the ATS points close (actually when they are a few thousandths of an inch from closing which is when they will arc if there is a load), better to turn them off.

Re: Installing Soft Starts on your air conditioners

Reply #6 –
I know "saving the ATS" is one reason for turning off loads, but in the case of starting the generator while driving (Chuck's question) is there not another equally valid consideration?

I have read that it is easier on the generator innards to start it up without a load.  This allows the RPM and frequency (Hertz) to stabilize before the voltage regulator is hit with the "high" power demand.  High as in one or two roof A/Cs already turned on and ready to rumble.

Also, there was something "bad" about turning the generator OFF while it was powering high demand loads...but I don't remember what it was.  Nothing to do with the ATS - something about suddenly chopping the power flow...  Above my pay grade.  Any EE major know?

Re: Installing Soft Starts on your air conditioners

Reply #7 –
We have the delays on our airs, but still have them off when starting gen or connecting to shore power!  Just good practice!

Re: Installing Soft Starts on your air conditioners

Reply #8 –
Quote from: wolfe10 –
Really depends on your individual set up.  If your air conditioners have a DELAY before starting, no need to shut them off.  But, if they start the instant the ATS delay is over and the ATS points close (actually when they are a few thousandths of an inch from closing which is when they will arc if there is a load), better to turn them off.
My airs have a delay and driving up 395 in the summer sometimes I need support for the dash air. Don't plan on pulling off the freeway to turn off air to start the genny.

Re: Installing Soft Starts on your air conditioners

Reply #9 –
Quote from: craneman –
My airs have a delay and driving up 395 in the summer sometimes I need support for the dash air. Don't plan on pulling off the freeway to turn off air to start the genny.

Good choice!

Re: Installing Soft Starts on your air conditioners

Reply #10 –
Quote from: craneman –
...driving up 395 in the summer sometimes I need support for the dash air. Don't plan on pulling off the freeway to turn off air to start the genny.
Little side note here:  The Atwood Air Commands we installed last year came with wireless remotes.  I hadn't actually thought about it before, but these would be a great help in the situation you mention.  I can turn both our roof units On and Off plus adjust the temperature from the comfort of the driver seat.

No more having to send the copilot back to operate the A/Cs!    :thumbsup:

Re: Installing Soft Starts on your air conditioners

Reply #11 –
My coach came with one thermostat that controls both airs has separate programmable start and start times and can auto from air to heat. Really don't want to give that up.

Re: Installing Soft Starts on your air conditioners

Reply #12 –
Quote from: Chuck & Jeannie –

Also, there was something "bad" about turning the generator OFF while it was powering high demand loads...but I don't remember what it was.  Nothing to do with the ATS - something about suddenly chopping the power flow...  Above my pay grade.  Any EE major know?

Need to shut the AC's off and let the generator run for a little bit to let generator cool down before shutting it off.  All of big generators with electronic control that I know off will run for a minute or more with no load before they shut down.

Re: Installing Soft Starts on your air conditioners

Reply #13 –
I see soft starts for sale @$98. Are they different than the ones you pay $300 for? Looks like they do the same thing. Please don't reply "you get what you pay for". I'm interested in the difference if anyone knows. Sometimes if the item has "marine" or "RV" attached the price is higher for no reason.

Re: Installing Soft Starts on your air conditioners

Reply #14 –
Quote from: Twig –
I see soft starts for sale @$98. Are they different than the ones you pay $300 for?
Would be easier to answer your question if you post a link to the $98 units.

Link below to the one I bought.  Haven't installed it yet.  I don't know if it is "worth" $300 or not.  It got good reviews...FWIW.

EasyStart 364 (3-ton) Single Phase Soft Starter for Air Conditioners –...

Re: Installing Soft Starts on your air conditioners

Reply #16 –
Twig,  Easy Starts are different from Soft Starts.

The much less expensive Easy Start stops the current draw for the fan till the compressor is started.  Then starts the fan.  The start up surge for the compressor is still there, just not added to the current draw of the fan

Soft Starts stops the start surge of the compressor by slowly ramping up the current available to the compressor.  Takes more electronics to do that.

My clamp on amp meter, which does not sample fast enough to see the instant peek surge which can be as high as 70 amps, measured 40 amps on compressor start settling down to 15 amps for the compressor and fan.  With Soft Starts, it measured 4, then 6, then 10, then 12, then 15 amps.  Does not take long to get to 15 amps but no spike caused by the surge.

Hope this helps
 

Re: Installing Soft Starts on your air conditioners

Reply #17 –
Yep.