[RE-wrenches] Magnum MS4448AE Compatibility Question

[Hans Frederickson]

A few years back, we had a customer who was having similar problems. I don't
recall if it was a Buderus boiler, but the generator was a Generac. This was
a simple generator backup system. We were able to get the boiler to work
reliably after adjusting the governor on the generator so that it ran at
60Hz under load. As I recall, it would then drift above 60Hz when unloaded.

If you were to try a UPS, it would need to be a dual-conversion type to make
a difference, otherwise it would just pass the generator power straight
through. True dual-conversion UPS units are very expensive... Probably
costing more than the cheap generator in many cases.

-Hans

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Howie
Michaelson
Sent: Wednesday, February 11, 2009 6:52 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Magnum MS4448AE Compatibility Question

I installed an off-grid system with identical symptoms:

OB VFX 3648 dual stack
Buderus GB142-24
Kohler 12 kW propane genny

The boiler runs fine on the inverter power, but will occasionally error out
(6A) and shut down while the generator is running (usually after it has been
on for hours).  The plumber installed an APC uninterruptable power
supply/surge suppressor (not sure of the model) before the boiler, but when
running on the internal inverter, the symptoms seemed to get worse.  When
running on just the surge suppressor portion, the symptoms were the same as
if the APC wasn't in-line.  We've checked the grounding at the genny, made
sure the neutral was isolated except for the main panel, still the same
problem.  Seems this is a Buderus issue (or at least not an inverter one) -
see:

http://www.buderus.net/Support/TechnicalInfoForums/tabid/132/forumid/15/thre
adid/4334/scope/posts/Default.aspx

I haven't been able to make the boiler run reliably when the genny is on,
which is a problem in our climate, when the client goes away in the
winter...

Howie
--
Howie Michaelson
NABCEP Certified Solar PV InstallerT

Sun Catcher, LLC
Renewable Energy Systems Sales and Service VT Solar & Wind Incentive Program
Partner http://www.SunCatcherVT.com
(cell) 802-272-0004
(home) 802-439-6096


On Wed, February 11, 2009 7:47 am, Darryl Thayer wrote:
> Some of the hot surface ignitors I have seen draw a lot of current, in 
> the order of amps.  I would expect the inverter to drop out if it were 
> overloaded however.  Also does the magnum drop voltage at very low loads?
> Where the furnace controls can not function due to low voltage or poor 
> wave shape.
>
> Darryl
>
>
>>
>> This may be true about high frequency switching interfering with 
>> something, but I believe the problem with this ignitor is that it is 
>> a very poor design. Judging by what I read on their company forum, it 
>> doesn't look like they have a clue about this problem. Maybe you can 
>> go inside the Buderus and filter something there or maybe you can 
>> fine another product to try ?
>>
>> boB



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