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Old 20-07-2016, 17:53   #16
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Re: Generator

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Originally Posted by StarryHorizons View Post
Okay, I have another dumb question. (I was really hoping I'd be able to move past these at some point...)

Our Helia has the exact same generator seawater pump and strainer setup as shown. However, there have been a few times where I discovered we had a destroyed impeller when the generator gave me a Raw Water Flow alarm. Theoretically, if the seawater pump/strainer set up is basically the same as the one shown by Impi, shouldn't I always have enough water flow, even if the impeller has lost some/most of it's blades?

We have the same setup on our L450 and occasionally get the Raw Water Flow alarm or Gen shut off when using the Gen underway in rougher water. Is that what you are experiencing?

We do not have any impeller installed as the electric pump handles the water flow.


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Old 21-07-2016, 01:58   #17
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Re: Generator

An external lift pump and strainer is a good idea. Removing the water pump from inside the genset casing is a very attractive improvement.

It's not just Onans. My Paguro diesel genset had water pump issues; the shaft seal disintegrated and the fully functioning impeller sprayed salt water over every component within the sound proof casing. This problem wasn't assisted by the fact that Paguro positioned the water pump at the very top of the machine. Corrosive salt frosting everywhere.
They are designed in Italy! The following words should never be in a sentence without a NOT; Italian, Electrical and Reliable.
Oh, for an Onan.
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Old 21-07-2016, 03:10   #18
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Re: Generator

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Originally Posted by Catopia View Post
We have the same setup on our L450 and occasionally get the Raw Water Flow alarm or Gen shut off when using the Gen underway in rougher water. Is that what you are experiencing?

We do not have any impeller installed as the electric pump handles the water flow.


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The Onan has a pressure switch in the end cap of the heat exchanger. There are several things that can cause it to shut down. If you are still running an impeller in the primary pump and it is damaged the veins can break loose then get up to the end cap and actually block the water at the switch.

In rough water you can loose the prime to the March pump. Since they are not self priming it can take a little time to reprime them. The lack of water flow will shut it down. You might want to install a check valve at the top of the water intake to stop the back flow coming off a large wave.

Jay
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Old 21-07-2016, 05:32   #19
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Re: Generator

Quote:
Originally Posted by tuskie View Post
An external lift pump and strainer is a good idea. Removing the water pump from inside the genset casing is a very attractive improvement.

It's not just Onans. My Paguro diesel genset had water pump issues; the shaft seal disintegrated and the fully functioning impeller sprayed salt water over every component within the sound proof casing. This problem wasn't assisted by the fact that Paguro positioned the water pump at the very top of the machine. Corrosive salt frosting everywhere.
They are designed in Italy! The following words should never be in a sentence without a NOT; Italian, Electrical and Reliable.
Oh, for an Onan.
What you describe, is exactly what happened to my NexGen, which is assembled in the US and uses a Jabsco pump, it is why I went to the March AC pump, it's not an Italian thing, or even a Multi Hull thing
It seems my electrical components survived, but I had coated everything with Corrosion-X, that may have helped
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Old 21-07-2016, 15:14   #20
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Re: Generator

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Originally Posted by a64pilot View Post
What you describe, is exactly what happened to my NexGen, which is assembled in the US and uses a Jabsco pump, it is why I went to the March AC pump, it's not an Italian thing, or even a Multi Hull thing
It seems my electrical components survived, but I had coated everything with Corrosion-X, that may have helped
Thanks for that. Sharing tales of woe and hard-learned lessons is a great aspect of this forum.
Has the changed water pump arrangement on your NexGen made it more reliable? Stopping regular internal salt water showers must surely improve performance.
I'm glad your NexGen has survived the dousing. Our Paguro has had subsequent electrical breakdowns.
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Old 21-07-2016, 15:31   #21
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Re: Generator

Well jury is still out, but a little over 200 hours and it's still going, I am a firm believer in Corrosion-X
It seems everybody's impeller pumps are so problematic on generators that I don't see why they are even used.
Odd that the ones for main engines do not seem to suffer the same woes, because they are bigger? But all little outboard motors essentially run impeller pumps and last for years?
Im sold on using the 120 VAC pump, originally I was going to keep a complete Jabso pump as a spare, but now I just keep a spare March pump, that covers both AC's and now the generator, simplifying spares.


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Old 21-07-2016, 16:27   #22
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Re: Generator

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Originally Posted by Steve_C View Post
I just ran across a YouTube video a few days ago discussing this problem. They basically removed the Onan impeller and used an external pump to supply water and completely eliminated the problem.

I was just thinking of that video and you beat me to it. Looks like aq pretty good set up
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Old 14-09-2016, 11:53   #23
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Generator

Helia 44 owners,

The older I get the less dumpster diving I like to do.

The Helia 44 generator locker is pretty deep with a sharp cross rib at the bottom.

Not a place to make any missteps.

Started out with the 2 long no-skid strips, but found that was still a bit unsafe.

Added a few 6" wide x 11" inch long steps. Its like a walk in the park now.
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Old 09-03-2017, 11:45   #24
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Onan Generator Cross Reference parts list

Helia 44 Owners,

Here is the Cross Reference parts list for the Cummins Onan Diesel Generator

Both are the same generators just configured differently.

9.5 MDKBM 5872G, 50 hz, 1500rpm

11.5 MDKBM 5872G, 60hz, 1800rpm

See attachments.
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Old 13-03-2017, 08:42   #25
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Re: Generator

hello tell me please
does enybody change anod catamaran Hela 2014?
anod is outside of generator 9.5 MDKBM?
if you see frontside it is right Bottom far corner.
thank you
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