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I second Dana's response. I have observed that the MS4448 waveform
quality degenerates quite rapidly with imbalanced loading of one or the
other of the 120 volt output legs. I can't give a quantitative (%
distortion/amps) number to it, but I would classify it as severe. I
first noticed it when doing some test measurements in the shop, and found
large discrepancies between various current metering devices I was using,
as some of the meters were not measuring RMS, and the distortion was
throwing them way off. And when using 120 volt motors, even though
their surge may be well within specified load limits, count on things not
going well.<br><br>
I'm generally satisfied with the Magnum MS4448, but this is one the two
key shortcomings that I see with the product. The other is the idle
power draw when not in search.<br><br>
John Raynes<br>
RE Solar<br>
Torrey, UT<br><br>
<br>
At 11:16 AM 2/9/2009, you wrote:<br><br>
<blockquote type=cite class=cite cite="">
<font face="Times New Roman, Times">Wrenches,</font> <br>
<font face="Times New Roman, Times">We have an unusual problem, and I
need to know if anyone else has had this or a related problem, and what
to do about it.<br>
</font><br>
<font face="Times New Roman, Times">This concerns a new off-grid
residential system, very conventional: 1,800W PV, Midnite E-Panel with
Magnum MS4448-AE inverter, MX60, 16 S-460s, installed summer 2008. This
existing home is being extensively remodeled, and the home is not yet
occupied. A local mechanical contractor installed a new infloor radiant
(gypcrete) hydronic heating system using a Netherlands-made (German
company) Buderus GB142 high-efficiency boiler. The problem is that the
boiler won't start reliably on the inverter. It appears that the
hot-surface igniter does not get full AC voltage (it runs on straight
120V AC, but is supplied through the boiler's control circuitry). We
tested the igniter by disconnecting it and plugging it straight into
inverter AC and it lit right up. <br>
</font><br>
<font face="Times New Roman, Times">The mechanical contractor has tried a
replacement Buderus GB142 boiler with the same result. I was told that
they brought out a generator and it also failed to ignite on generator
AC, but not knowing the generator used or the way it was wired (I believe
an extension cord to a portable) I don't put much weight on this data.
They also took a Lochinvar Boiler to the site to test the theory that a
different manufacturer's boiler might work. The Lochinvar boiler, which
uses a different control and a spark ignition rather than a hot surface
igniter, worked on site without any problems.<br>
</font><br>
<font face="Times New Roman, Times">I'm looking for solutions. Magnum
tech support had not heard of this. Have you? </font><br>
<font face="Times New Roman, Times">Also, if indeed we have an inverter
that is incapable of running this load, how do we make it right to the
homeowner and the mechanical contractor? What should be Magnum's
obligation? What should be ours? This issue hasn't come up here since the
days when the Trace SW mod-sine series was the waveform standard.<br>
</font><br>
<font face="Times New Roman, Times">Thanks,</font> <br>
Allan Sindelar <br>
<font size=2 color="#0000FF"><u>
<a href="mailto:allan@positiveenergysolar.com">
allan_(at)_positiveenergysolar.com</a></u></font> <br>
<font size=2>NABCEP certified solar PV installer</font> <br>
<font size=2>Positive Energy, Inc.</font> <br>
<font size=2>3225A Richards Lane</font> <br>
<font size=2>Santa Fe NM 87507</font> <br>
<font size=2>505 424-1112</font> <br>
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