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Author Topic: Prevost Shorty Update  (Read 2040 times)
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« on: April 18, 2010, 04:46:01 PM »

Well so far:

Installed a 50 amp circuit in my storage shed, so I could use shore power without blowing a GFI circuit.  (Why the GFI would blow I do not know)

Got the coach charging system to work both on shore power and Gen set by finding the right sequence of switches to throw and in the right position, and pushing the converter circuit breaker in and out a few times. Sad

My issues with the heat exchanger are well documented and should get my new coil on Monday and will bring it to the radiator shop for a rebuild.

In the mean time will be taking out the other leaky heat exchanger which is an even worse location than the first.  On the Liberty conversion they put the first cruise air unit right behind the driver in console that used to have the TV set on top of it.  Also inside the console is a receiver, and tape deck, circa 1979.  The heat exchanger is underneath both of them.   Going to try to take out the receiver and the tape deck, and remove their shelves to get at the heat exchanger.  There will be some descriptive language used, I can already predict.

Going to take out the front drapes, they are more than a little dirty - icky dirty - going to try and have them dry cleaned.

My oil sample came back from C&J and everything is in the normal range, and we have a good start for a comparison to be made later.
On my Prevost there is no coach air, but rather a tiny automotive compressor driven off the engine, linked to a evaporator by the driver, they use the 3 Cruise Airs for over the road ac.

I have a 40,000 Btu Espar air unit, that will turn on the blower but will not ignite.  Going to call a couple of Espar dealers locally to see if any of them have ever worked on this old a unit.

Building (assembling) shelves for my storage unit, so I can store more stuff Wink

Next week going to add water and see if anything grows.

Stillwater Mn

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'75 MC8 8V71 HT740

« Reply #1 on: April 18, 2010, 06:14:58 PM »

Beware, if the GFI was tripping with the coach plugged in, then there's current in the ground wire.

A potential for a live coach is not good!

Something, somewhere, is putting power to the body of the coach.

Neutrals tied to ground in the coach someplace?

happy coaching!

Frozen North, Greater Toronto Area
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« Reply #2 on: April 18, 2010, 07:36:54 PM »

if he has an inverter, that will cause the gfi to pop.  we have to uninstall them at the bus rally every year, then put them back on when we leave.  somehow, almost all the buses tripped them at the rally.

1991 Eagle 15 and proud of it.
8V92T, 740, Fulltime working on the road.

Fran was called to a higher duty 12/16/13. I lost my life navigator.
Orange Blossom Special II
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73' MC-8 8V71/HT740 Southwest Florida

« Reply #3 on: April 19, 2010, 05:15:56 AM »

Most inverters have a neutral/ground bond in them (code requires neutral & ground to be bonded at the source, and only at the source), so this bond has to open when connecting to shoreline or generator. The problem arises when the GFI senses the neutral/ground bond and opens before the bond in the inverter can open.  Jack

Growing Older Is Mandatory, Growing Up Is Optional
Arcadia, Florida, When we are home
Sam 4106
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« Reply #4 on: April 19, 2010, 06:53:52 PM »

Hi chuckd,

As I recall your bus has a manual transfer switch. If so, I'll bet that the neutrals are not switched. I worked on a 1982 Prevost that had been converted by Magic Carpet (forerunner of Marathon Coach) that had an automatic transfer switch with 3 pole contactors but they only switched the two hots. All the neutrals were tied together. It would trip a GFI every time. Isolating the neutrals from shore, generator, and inverter solved the GFI tripping problem. If you are not familiar with electrical work you may want to hire a professional to do the work or at a minimum to advise you.

The drapes in our MC8 were also pretty dirty. My wife asked about having them dry cleaned and the cost of pressing the pleats ($1.75 each) was prohibitive. She washed them in our home washer, on the gentle cycle, line dried them, and ironed the pleats herself and they turned out fine.

Good luck, Sam MC8

1976 MCI-8TA with 8V92 DDEC II and Allison HT740
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