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SMX Controls vs. 3 Knob Controls - Reliability ?
September 21, 2009
1:22 pm
Steve Pooler
Forum Posts: 1127
Member Since:
November 12, 2008
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Sure…Be happy to comment  Laugh

As I said earlier and you quoted…There were some early problems that seem to have been ironed out…Sometimes it was as simple as a vendor not supplying a good single component…Others times it was fault in design…

Now days the failures are much more rare…But as with anything electronic there are some risks of over voltage, surges etc…

I have serviced these controls up & down the West Coast of Florida (Some call it the Lightning Capital of the World) for many years…and have many customers with Multiple Digital systems aboard…It's hard to find the manual controls aboard a boat anymore that's less than 30 years old…And even most of those have been retrofitted…

You want to know why ???

The Advantages…Far Outweigh the disadvantages of the occasional failure…

Yes a board can be expensive, but think about that compressor running on low voltage, without water, or No freon….A compressor change out is much more labor intensive, with freon, evacuation & soldering involved…Not to mention a compressor is a much more expensive part than a circuit board…

The compressor (& reversing valve) failures we have seen since the digitals have become main stream are greatly reduced when compared to the old manual days…I bet I used to change a compressor a month, at least back then…now I see maybe one a year…and that one compressor this year was shorted to ground…It was also in an unmatched split system…

Add to all that…The much better cabin temp control, being able to accurately set it, the humidity removal while away function, and auto fan speed control to reduce noise…Plus the extra Year of warranty with digital protection…

People want it…

I also know that when I do a single retrofit on a older system…The people almost always call back for another on one of the other systems aboard….

Here's my final take…

If they were that bad…The public would all be going back to the old controls…(Which they can still do) but..

It's kinda like saying…I don't want electronic ignition in my car…Lets go back to points & condensers…Some folks did that too back then…

Let's face it…Certain folks even today…Just don't like computers and are afraid of them still…Guess they won't be reading this  Wink …But Hell…My mom can't work the remote for the TV & Cable Box even to turn both on & off….It's always that Dam things fault !!!…

I say more power to them…you sometimes can't fix that… But I Will Fix, Sell, or put in whatever they want, or feel comfortable with…I've been around long enough to have worked on both type systems, and have the experience to be comfortable with what ”They” are either way  Cool


September 21, 2009
12:11 pm


I like your thinking and I have been thinking Stowaway would be preferable to Zephyr on Envirocomfort. I like digital "stuff", I like added protections, and the ability to read faults on a display. 

 Funny thing is I have been getting some feedback from my service manager (Mark) in the BVI. As you know I was interested in standardizing to the SMXht display/keyboards (since I already own one).Here is some feedabck I just got from Mark: 

 I appreciate what you are trying to do here, but a word of warning - we actively moved away from the digital SMX remote control panels some time ago, as the failure rate was unacceptable. All our new installations carry the rotary 2 or 3 knob controllers now, and we are happy with the result.

My charter company has about 40 boats in their fleet, so they don't lack personal experience. Charter Boats do take an exceptional amount of use (abuse!) and are probably a good "testing ground" for anything!

I read (again) through your post on Marine A/C controls. I noted that in reference to Digital Controls you say that they: 

Started hitting the market in the mid 80's...They at first like any new product, had a few weaknesses and thus some early problems, but as they matured they have now become the standard, and are very reliable. 

It may be that the charter company gave up on the digital controls after some early failures. Could you elaborate  more on the failure rate on the SMX prologic boards. I see them regularly advertised on websites, eBay, etc... so that makes me think that the board are in need of replacement on a fairly regular basis?