On 12 Aug 2006 23:46:46 -0700, "Akka" wrote:

We continue to have problems with our engine-driven refrigeration
system, and wondered if anybody knows what we might be doing wrong. We
keep on blowing up compressors -- either they start to leak after a
couple of months use, or they fail (i.e., no longer bring down the
low-side pressure to a vacuum). We know it's not from 'slugging' ice,
because we routinely monitor the state of the return line about 4 feet
from the compressor, and it's never frozen. When the compressors leak,
we naturally don't know it until the fridge doesn't cool anymore, when
we look at the sight glass and see it's empty. This entails running
the system for 5 minutes or more, empty, because that's how long it
takes for liquid to appear in the sight glass when the system is full.
Is that a long enough time to ruin the compressor? The last time we
opened the system up, we found some black residue blocking one of the
filters at the expansion valve. Any idea how dirt could have gotten
into the system? Maybe from a compressor going bad? How do you clean
it all out?

When compressors go bad, they usually leave metal flakes at the
expansion valve filter. Black gunge suggests incompatible oil, or
inadequate flushing when changing refrigerant type.
You replaced the dryer/reservoir of course?
You filled with the recommended type and quantity of oil, I expect?
You DO have an electric clutch on the compressor drive, I suppose?
There is a cutout to the clutch for underpressure/overtemp, I expect?

Brian Whatcott Altus OK

All engine driven refrigeration compressors were intended to be used on
automobile air conditioning and not for medium to low temperature
refrigeration. In most cases if a compressor had a good service life in
an automobile it could work in a lower temperature system if the system
is designed correctly. If an engine drive refrigeration system is
designed and installed correctly the compressor will operate for twenty
plus years this is a proven fact. Engine driven systems designed by the
original companies of Crosby and Grunert were still running with the
same compressors, these were installed in the late 1970's.

There are a small percentage of new and rebuilt compressors that do
fail prematurely in the first twenty five hours but repeated compressor
failures are preventable. There are a number of reasons why the engine
driven compressor fail:

Compressor capacity is excessive for the size of holding plates; If a
compressor is putting out enough energy to freeze a 500 pound holding
plates in one hour and the plate only weighs 50 pounds the refrigerant
and oil return will not be adequate for lubrication or compressor
cooling, because the expansion device won't allow the flow. The
colder the plates are the less flow of needed refrigerant and oil.
Remember the compressor was designed for high back pressure
applications.

Too large an expansion valve for the evaporator coils in holding
plates; During the off cycle when holding plates are colder than
compressor refrigerant mixed with oil will migrate to the cold plates.
Then after start up with a large valve orifice there will be a quick
flood of this liquid mixture flooding back to compressor causing stress
on reed valves and connecting rods. Some systems must have suction line
accumulators to reduce the liquid return to an acceptable level.

Improper type of refrigerant and oil; Most engine driven refrigeration
systems violate the basic principles of refrigeration, Condensing unit
and return line along with evaporator should be designed to allow
gravity to assist in liquid return, Each component in the system must
be able to match the capacity of the compressor. Oil return will
always depend on miscibility in our boat refrigeration systems, R12 and
mineral oil are miscible, 134a or R12 and polyester oil are miscible
all other refrigerants lack different levels of miscibility at low
temperatures.

Too large of a line in holding plate or anywhere in low pressure side
of system will cause oil accumulation and compressor oil starvation.

Too small of a line or restriction in low pressure side of system will
cause oil accumulation in lines and very low compressor suction
pressure.

"Akka" wrote:

We continue to have problems with our engine-driven refrigeration
system, and wondered if anybody knows what we might be doing wrong. We
keep on blowing up compressors -- either they start to leak after a
couple of months use, or they fail (i.e., no longer bring down the
low-side pressure to a vacuum). We know it's not from 'slugging' ice,
because we routinely monitor the state of the return line about 4 feet
from the compressor, and it's never frozen. When the compressors leak,
we naturally don't know it until the fridge doesn't cool anymore, when
we look at the sight glass and see it's empty. This entails running
the system for 5 minutes or more, empty, because that's how long it
takes for liquid to appear in the sight glass when the system is full.
Is that a long enough time to ruin the compressor? The last time we
opened the system up, we found some black residue blocking one of the
filters at the expansion valve. Any idea how dirt could have gotten
into the system? Maybe from a compressor going bad? How do you clean
it all out?

We have an engine driven/shore power refrigeration system that can be done either way.
The key to our particular system is not to run the engine driven refrigeration more than
45 minutes at a time. We normally do it once in the morning and once in the evening. If
you run it for more time than that, the fluids disappear to somewhere and the compressor
freezes up. We have been running ours that way since we bought the boat in 1998 (on
instructions from the PO who had the same problem as you seem to be having with blown
compressors), and have had no problems with it.

The only other thing is that we always check to see that water is coming out the exhaust
(like we do with the engine). When we run it on shore power the time isn't as critical,
but we do about the same as when we are using the engine. Otherwise it will sometimes
stop itself when it gets really cold, although it doesn't seem to hurt it when it does
that.

grandma Rosalie

S/V RosalieAnn, Leonardtown, MD
CSY 44 WO #156
http://home.mindspring.com/~gmbeasley/id1.html

In article .com,
"Akka" wrote:

We continue to have problems with our engine-driven refrigeration
system, and wondered if anybody knows what we might be doing wrong. We
keep on blowing up compressors -- either they start to leak after a
couple of months use, or they fail (i.e., no longer bring down the
low-side pressure to a vacuum). We know it's not from 'slugging' ice,
because we routinely monitor the state of the return line about 4 feet
from the compressor, and it's never frozen. When the compressors leak,
we naturally don't know it until the fridge doesn't cool anymore, when
we look at the sight glass and see it's empty. This entails running
the system for 5 minutes or more, empty, because that's how long it
takes for liquid to appear in the sight glass when the system is full.
Is that a long enough time to ruin the compressor? The last time we
opened the system up, we found some black residue blocking one of the
filters at the expansion valve. Any idea how dirt could have gotten
into the system? Maybe from a compressor going bad? How do you clean
it all out?


What you need is AN ELCTRIC CLUTCH on that compressor, so that it only
runs when the Refer needs to cool itself. Almost every Car A/C has
one, and for the same reasons you NEED one. Also does you compressor
commect to the rest of the system with some kind of vibration proof
hoses or flexable piping? Now there is a novel idea. Keeping the engine
vibrations out of the refer system.

Me

Akka wrote:
We continue to have problems with our engine-driven refrigeration
system, and wondered if anybody knows what we might be doing wrong.


After reading all the posts so far, I got to admit I do not think I
make enough money and lack the skill to maint a refer system.

So why do you "need" a refer system when most the worlds population
lacks such amenities?

This morning I got up had my oat meal, soy milk, and a few raisins.
Umm........ The soy milk aint milk but the light chocolate soy is
great! Shelf life is about on year. For lunch I think I'll have some
rice, fish, and some veggies. Maybe for dinner a little pasta, veggies,
olive oil, parmesan. Ummmmmm. Oh, and a nice 84 degree F beer. The hops
really stand out over 80 F! Get a good south pacific beer brewed
locally and its got to taste good at 84 degrees. Why? Uhh, who do think
is buying it? Later a snack: fruit salad, pineapple, mango, banana, and
that weird pokey thing that tastes like Juicy Fruit Gum. And speaking
of Hawaiian styled Poke. Nothing like a nice bowl of raw fish. Ummm.

Hey........ just a second! Non of that needed a refer?!?!?

So why do you need a refer? Oh I forgot. For all the visitors when tied
at the dock. I do not do much entertaining. I enjoy sailing. One of the
first things I threw overboard was that cocktail table in the cockpit.
Damn thing kept flapping around when surfing down 20' seas. Also
removed the salon table. Now that was a waste of space. But will be
able to recycle both for various boat projects.

And no I do not think cursing should be "camping in the sixteenth
century."

All a person needs do is cruise, pick up handy ways of living from
people not raised in a Wal-Mart. But if everyone did that our economy
would crash. How much of our GNP is from consumer purchasing????

Hi Bob,

From your post it seems as if you are advocating one specific standard
for all cruisers. Perhaps I'm reading in more than you intended, if so
I apologize, but it seems to me that there is no one "true" solution to
how much luxury or hardship one should endure while cruising.

Instead, I would suggest that the would be cruiser treat it as an
economics issue similar to "How much luxury can you afford while on
vacation?" To better illustrate this I'd use two extreme examples, then
work towards the middle.

If you are the Prince of Monaco, then anything short of 5 star hotel
service on a mega yacht is roughing it - but only because he can afford
it - this would mean having unlimited water, ice, fresh food,
communication, entertainment, etc.

If you are dirt poor, than anything that requires power (all of the
above) are beyond one's means and would be sacrificed in order to allow
for the basic costs of cruising. There are many famous boaters who've
written books about sailing with only limited water on a small boat
without a motor or VHS. Joshua Slocum sailed around the world this way,
but I doubt most others would have enjoyed the trip.

In them middle are the rest of us. I'd suggest that one's standards
should reflect what one feels is appropriate for their life style and
economic situation. Perhaps the original poster would be happy without
fresh milk, but perhaps they wouldn't.

It seems unreasonable to me to say "Don't go cruising unless you are
willing to sacrifice". Instead, I'd suggest that one take only those
amenities one can afford.

In understanding exactly how much refrigeration (or any other amenity)
does cost, including maintenance and repair, especially if one is unable
to do this themselves, one can then judge whether an item is
appropriate. That means having a very real budget a priori and placing
all of one's requirements in the perspective of what can be included in it.

Not a definitive answer to the original question, but certainly an
algorithm that can be applied to any cruiser's "luxury" issue.

Cheers,

Robb


Bob wrote:
All a person needs do is cruise, pick up handy ways of living from
people not raised in a Wal-Mart. But if everyone did that our economy
would crash. How much of our GNP is from consumer purchasing????

"Bob" wrote:


Akka wrote:
We continue to have problems with our engine-driven refrigeration
system, and wondered if anybody knows what we might be doing wrong.


After reading all the posts so far, I got to admit I do not think I
make enough money and lack the skill to maint a refer system.

So why do you "need" a refer system when most the worlds population
lacks such amenities?

What does that have to do with anything? Most of the world's
population doesn't have good health care. Some of them don't have
enough food or water. Why should you assume that I would want to be
like most of the world's population?

This morning I got up had my oat meal, soy milk, and a few raisins.
Umm........ The soy milk aint milk but the light chocolate soy is
great! Shelf life is about on year. For lunch I think I'll have some

My husband drinks soy milk because he is lactose intolerant. I
normally have a bagel (untoasted and with no cream cheese) for
breakfast, or we have bacon. But what I have for breakfast and
whether I need refrigeration to have that isn't really any of your
business. And it isn't really helping with this question is it?
Which was NOT how can I get by without refrigeration.

I have enjoyed reading Annie Hill's book - she does without
refrigeration, as do the Pardeys. But I can decide on what to take
from their books by myself.

rice, fish, and some veggies. Maybe for dinner a little pasta, veggies,
olive oil, parmesan. Ummmmmm. Oh, and a nice 84 degree F beer. The hops
really stand out over 80 F! Get a good south pacific beer brewed
locally and its got to taste good at 84 degrees. Why? Uhh, who do think
is buying it? Later a snack: fruit salad, pineapple, mango, banana, and
that weird pokey thing that tastes like Juicy Fruit Gum. And speaking
of Hawaiian styled Poke. Nothing like a nice bowl of raw fish. Ummm.

Hey........ just a second! Non of that needed a refer?!?!?

So why do you need a refer? Oh I forgot. For all the visitors when tied
at the dock. I do not do much entertaining. I enjoy sailing. One of the
first things I threw overboard was that cocktail table in the cockpit.
Damn thing kept flapping around when surfing down 20' seas. Also
removed the salon table. Now that was a waste of space. But will be
able to recycle both for various boat projects.

And no I do not think cursing should be "camping in the sixteenth
century."

All a person needs do is cruise, pick up handy ways of living from
people not raised in a Wal-Mart. But if everyone did that our economy
would crash. How much of our GNP is from consumer purchasing????

Rosalie B. wrote:
"Bob" wrote:

But what I have for breakfast and
whether I need refrigeration to have that isn't really any of your
business.

Granny, I do belive you are baiting me into a fight.


And it isn't really helping with this question is it?
Which was NOT how can I get by without refrigeration.


Sure it is. rip it out and free himself of the frustratin and down time
fixing it.


I have enjoyed reading Annie Hill's book - she does without
refrigeration, as do the Pardeys. But I can decide on what to take
from their books by myself.

True, personally I belive the marketing stratigies in the united states
are rather robust and efective. It certainly has you bamboozled.

All a person needs do is cruise, pick up handy ways of living from
people not raised in a Wal-Mart.

Are you still angry from our last conversation?

Benevolent Bob

"Bob" wrote:


Rosalie B. wrote:
"Bob" wrote:

But what I have for breakfast and
whether I need refrigeration to have that isn't really any of your
business.

Granny, I do belive you are baiting me into a fight.

I thought that was you baiting me g


And it isn't really helping with this question is it?
Which was NOT how can I get by without refrigeration.


Sure it is. rip it out and free himself of the frustratin and down time
fixing it.

Our boat (which is a very old boat -1979) has a huge fridge
compartment something like 14 cu. ft. Way to big for just the two of
us. But it works, and Bob can keep it running so it isn't a problem
except for figuring out what to fill it up with.

There are all kinds of possibilities for boats - including a portable
12V fridge, or ripping the current fridge out and putting a newer
system in, or doing without. We are going with what we have for now.

But that doesn't help the OP, and I really think that he (or she -
don't remember which) could think of 'rip it out' for himself if it
was something he wanted to do. Possibly his SO doesn't want to do
without refrigeration.

I have enjoyed reading Annie Hill's book - she does without
refrigeration, as do the Pardeys. But I can decide on what to take
from their books by myself.

True, personally I belive the marketing stratigies in the united states
are rather robust and efective. It certainly has you bamboozled.

Marketing strategies for what? The books? The refrigeration? I'm
not buying anything.

All a person needs do is cruise, pick up handy ways of living from
people not raised in a Wal-Mart.

Are you still angry from our last conversation?

Benevolent Bob

I don't shop if I can possibly avoid it - not at Wal-Mart or anywhere
else. I bought Annie Hill's book at one of the first boat shows I
went to after we got our boat, and it made me want a junk rig (which
Bob wouldn't go for of course). Even people who shop at Wal-Mart may
have good ideas on occasion and I'm always on the lookout for such.
(although I'm not going to eat sushi)

Bob wrote:

Sure it is. rip it out and free himself of the frustratin and down time
fixing it.


Benevolent Bob

OK...so burn your house down and move into a tepee on the empty lot.
Don't forget to close off the water/sewer lines.

As to trying to convert me to your chosen lifestyle...you sound like a
lot of religious fundamentalists (pick any religion you want). "You
WILL _______ what I tell you to".