Micro-Air Easy Start Issues

[Kevin Means]

Every September, we meet other family members at a campground on the Colorado River, and the campground has 30 amp service only. It's always over 100 degrees during the day, and often in the 80s at night. Our coach has three Coleman Mach 13,500 BTU AC units with heat pumps and condensation pumps. It's no surprise that we can only run one AC unit, but at those temps, one AC unit obviously doesn't cut it.

I recently bought and installed two Micro-Air Easy Start 364 units, which they claim will allow you to run two 13,500 BTU AC units off 30 amp service, simultaneously. They do so by ramping up the compressor's start cycle, vs. its typical hard-start.

Their installation instructions direct you to disconnect some wires, tap into others and remove the factory start capacitor. The instructions are actually pretty straightforward, but the problem is, our Coleman's wiring is not as is depicted in their diagrams. It's close, but not identical. I'm thinking that's because ours also have heat pumps and condensation pumps, but I'm just guessing at that.

Despite interpreting the instructions as well as I can, I still can't get two AC units to run off 30 amp service, and when I remove (disconnect) the start capacitor, as instructed, my condensation pumps no longer work. I can hear the compressors trying to start, but after a few seconds, they shut off. Reconnecting the start capacitor gets the condensation pumps working again, but the two compressors still won't start on 30 amps. The only other appliance running is our res fridge.

I've sent two emails to "customer support" and while they've acknowledged receiving them, no one has responded. This the only way to contact customer support. There is no phone number to call. I've read all their FAQs, but nowhere is the issue of condensation pumps addressed. Has anyone with AC units that have heat pumps and condensation pumps installed these? If so, I'd love to hear if and how you got them to work. Thanks.

Kev

 

[Gary RV_Wizard]

I don't have any real help, Kevin, but it's my belief that the more recent and more energy efficient models of heat pumps already have hard start capacitors, so adding one doesn't help much (or at all). The standard caps on mine gave me about a 50% chance of both starting when on 30A with no other loads. If some other amp load was running, I had about zero chance of starting a second a/c.

Have you observed the amps displayed on your Powerline EMS when the 2nd a/c tries to start? You should get a pretty good picture of what the standard vs Micro caps does and whether there is much improvement.

Not sure why the condensation pump quits working when you swapped the caps.

 

[Back2PA]

Kevin, for my own edification what is the purpose of the condensation pump - pumping condensate overboard rather than dumping it on the roof?

 

[SargeW]

Kevin, for my own edification what is the purpose of the condensation pump - pumping condensate overboard rather than dumping it on the roof?

Yes, I have the same pumps on my rig. If I have 3 AC units running, they can produce a LOT of water runoff. 

Kev, I have the same AC units on my rig, just newer. I think Gary is correct, I can run 2 AC units on 30 amp as long as I turn off everything else I can.  The thing that helps though is that there is a system on my rig that will use the Inverter "in reverse" to supply 120 volt power from the battery bank when the amp draw exceeds the shore power. 

I know that it has jumped in and supplemented the shore power on 30 amp as I saw the draw on the power monitor.  Most likely when the refer kicked in and wanted to cool.

 

[garyb1st]

With the Onan 5500 generator running, my EMS indicates about 22-23 amps when both air conditioners are on.  Even when the compressor comes on, I don't see a spike at the monitor. 

 

[SargeW]

You may have EZ starts already Gary. I usually see about a 5 amp spike for about 5 seconds or so when a unit kicks in.  That's usually when my Magnum jumps in to help.

 

[John From Detroit]

I will say this.  I have run 2 A/C's on 30 amps (For about 5 minutes) as proof of concept.  The pair drew 27 amps. the only other thing turned on was the converter with full up batteries.  Now the fridge (3 amps and change) would have been enough to click the breaker.. My water heater today (Also 3 amps and change) would do it back then (12-5 amps) no  contest. NOTE that I did not have microstarts. .They Were Trump, er Carrier Air V's 13.5 Amps.  NOW I have 1500's I"d not try it. ONE has a soft start the other I dont' know. (Sounds like it does but it's factory)

ALso the condensers need to be CLEAN and I mean CLEAN or the pressure will increase and CLICK goes the breaker.

 

[Gary RV_Wizard]

my EMS indicates about 22-23 amps when both air conditioners are on.

That's about what I would expect from any recent vintage roof a/c unit.

Even when the compressor comes on, I don't see a spike at the monitor. 

That has to be a lack of sensitivity in the EMS amp monitoring, since it is impossible for the amps not to jump briefly when the compressor (or any motor) starts.  The +5 amps for a few seconds that SargeW observes is typical for a modern a/c unit. Older ones may jump 10.  You will read that the start-up amperage may double or triple and that's true, but in most cases only for a second.

 

[Kevin Means]

I (finally) got a response from Micro-Air today. It was rather lengthy as they explained current draw etc. They said they didn't know how much current the condensation pumps drew, and they were thinking that they might be pulling just enough power to prevent the compressors from starting. (Hmmm...) Then, at the end of their looooong explanation, they said, "To run both ACs at the same time, they must be the only loads present. An electric running fridge will not be able to run as well." (I wish their website and/or installation video would have mentioned that

Gary, our AC units have EZ Start capacitors that ramp up the compressors, but the Micro-Airs ramp it up even more. They supposedly "learn" the starting characteristics of a particular AC unit and adjust the ramping-up accordingly. (At least, that's what they claim.)

One of the condensation pump's power wires is directly connected to a terminal on the capacitor. When I saw that, I knew the pumps weren't going to work when I disconnected that capacitor. To their credit, the tech-rep said they'd help me find an alternate way of powering them, but I started hearing the Micky Mouse theme song in my head, so I'm not going to go that route.

Marty, our system has that feature as well. It's called "Inverter Assist" and it does allow me to run two AC units on 30 amps. I've watched my Trimetric when it kicks on and wow... it pulls some serious amps (DC). That's why I wanted to try these Micro-Airs - to reduce or eliminate that deep surge. I guess I'll just have to live with it.

I guess the moral of the story is, if you've got a res fridge, don't bother with Micro-Airs. Thanks for your help everyone.

Kev

 

[Kevin Means]

Well, here's a surprising update... They're working. I don't understand what happened to get them working, but they're working.  I went out to the RV to remove them, to ship them back, but I decided to test them one more time. Lo and behold, both AC units kicked on while the res fridge was on AND while its compressor was running.

The only thing I can think of, is that the Micro-Air's "learning" feature re-learned how to start two AC units instead of one. When I installed them, I went through the learning process one AC unit at a time. (It's a 5 cycle process)  However. when I tried to run both AC units simultaneously, they wouldn't start both compressors without the Inverter's "Inverter Assist" mode being on. After trying to start both AC units several times, I think the Micro-Airs have re-learned the startup process, but that's just a guess.

Despite what their tech rep said, I can start both AC units on 30 amps while our residential fridge is on and it's compressor is running. The "Inverter Assist" mode doesn't kick in and no loads have to be shed. Pretty impressive.

The images below were taken from my Precision Circuits monitor.

Picture 1 shows the amp draw of our residential fridge while the compressor is running.
Picture 2 shows the spike in amps when two AC units are turned on  (Zone 1). Only their fans are running. (That's the normal start-up process)
Picture 3 shows the spike in amps when the 1st AC compressor kicks on.
Picture 4 shows the spike in amps when the 2nd AC compressor kicks on.
Picture 5 shows that the inverter is in "Normal" mode. It would say "Inverter Assist" if the Inverter Assist mode was activated. It kicks in automatically and starts drawing power from the house batteries when the AC load exceeds 30 amps. Picture 5 also shows that no loads are being shed to enable the fridge and AC units to run.

I let the system run for about 10 minutes and the amp draw stabilized at about 28 amps. I guess if you're considering getting these so you can run two AC units off 30 amps, they do seem to work.

Kev

 

[Lou Schneider]

One of the condensation pump's power wires is directly connected to a terminal on the capacitor. When I saw that, I knew the pumps weren't going to work when I disconnected that capacitor. To their credit, the tech-rep said they'd help me find an alternate way of powering them, but I started hearing the Micky Mouse theme song in my head, so I'm not going to go that route.

One of the schematics I looked at connected the "common" terminal of the capacitor directly to the neutral side of the incoming power line and used it as a convenient tie point for several wires.  With the power off, use an ohmmeter to see if yours is connected the same way.

If so, I'll bet connecting the pump wire that went to the capacitor to the power line neutral will restore it's operation.  I find it hard to imagine that the small motor in the pump would have any use for a capacitor other than using it as a tie point.

 

[Kevin Means]

Lou, I forgot to mention that that's exactly what I did. I put a VOM on one of the wires they wanted me to disconnect, and determined that it was the 120 volt source for the pump. I reattached it to the capacitor and the pump started working again, so I'm leaving it attached. I left the other wire to that capacitor disconnected per their instructions. Everything seems to be working as advertised.

Kev

 

[SargeW]

I am not surprised by the tech's answer to you that it just won't work. I have found that when dealing with even experienced tech's, when they grow tired of trying to figure it out, or they just don't know the answer the easy way out is to announce that "it wont work".  That's why I often give it "one more shot" before I give in to that answer.

 

[Kevin Means]

You're absolutely right Marty. It's a pretty new product, and I think they're struggling with things like tech support. I was kind of surprised that none of their installation diagrams, or video addressed AC units with condensation pumps. And their response to my inquiry was just flat out wrong. Oh well

BTW... when I was reading their return policy on their website, it says they have a 25% restocking fee. I paid $600.00 (total) for two systems, so that means they'd have charged me $150.00 to return them. Seems rather steep and arrogant when you consider that none of their advertising material, or installation instructions address the issues of condensation pumps or res fridges.

Kev