On Tue, 2 Aug 2011 08:11:16 -0400, "Flying Pig"
wrote:



As to the gas, it takes all of 6 ounces to fully charge our system, so
hunting for bargains on cans isn't a high priority :{)) When we bought our
car here and the AC failed after some work on other stuff, the mechanic who
screwed it up claimed he'd put gauges on it and found no pressure (instead,
the failure of the AC to run was his neglect of not putting on the high-temp
alarm connection back on when he did some other work); I bought a can with a
trigger and gauge; it read 150# (and was able to return it immediately from
outside AutoZone where I'd tested it), so I knew he was full of ****. As to
the WalMart can lead Neal provided, it has oil, and Danfoss is adamant about
putting in nothing other than straight gas, so I'd get the one without, if I
went that route for charging (still have the challenge of attaching the
pop-on end, of course; perhaps I'd have to buy an adapter such as his boat
pic showed for the other end of the ell-connection on the gauges - anyone
have a name for that fitting? It would be one which screws onto a 134a tap,
not a standard R12 [or, at least, the gauges suggest it's only for 134a, so
I presume there's a difference]).


I can't venture anything more because I've only done automobile AC.
As I recall from having a R12 to 134A conversion done they use
different connectors.
My gauge manifold sets are post-R12.
Good you take only 6 ounces.
Most auto systems I've worked on take close to 3 lbs.
When one goes bad with a slow leak you end up losing a few cans before
all is said and done.
I like to have about 6 cans available.
Besides that I inject dye and oil separately as needed, and don't want
any "stop leak" products in the system.
One time an auto store I went into had only adulterated 134A.

--Vic

"Gogarty" wrote in message
...
How come Wilbur has not weighed in on this thread?

So far as I know the Danfoss compressors for marine fridges have only one
service port on the low side. When new it is sealed with a cap and black
gloop. Remove the gloop and the cap and you find an R34a-specific snap
coupling which mates to your vacuuum pump or charging manifold. I managed
to
set things up without a manifold or guages using a fitting that allows me
to
inject refrigerant directly into the low side port. You can vent excess
there
too with an Allen wrench pushing on the valve. Mine has been running
flawlessly (knock, knock) since I evacuated it and carefully injected
refrigerant using the frost line as a guide.




Wilbur has weighed in a time or two. . . Even posted a link to a photograph
of the r134a adapter for car A/C cans.

My Danfoss compressor has two service ports. One to connect the high
pressure gauge and one to connect the low pressure gauge. The port on top is
the suction or low pressure. This is where I add refrigerant. The port below
is the high pressure or compressed gas port. But, I don't bother with the
high pressure reading since there is no way to adjust it independently of
the low pressure side. Mine works great with seven to eight psi on the low
side. I haven't a clue what that amounts to on the high side. If I try to
add more than ten psi on the low side the thing won't keep running. It
cycles off and on as there is some safety circuit that turns it off so it
doesn't become damaged. It also draws too much amperage above 8psi. I like
to see it draw between 3-4 amps. It runs smoothly and quietly then. I like
to see the frost line inside the ice box as anything being cooled outside
the box is wasted effort and energy.

The electrical tape repair is still going strong. No leaks to date.


Wilbur Hubbard

Hi, all,

The plot thickens, of course - nothing seems simple with this
evacuation/recharge...

"Gogarty" wrote in message
...
How come Wilbur has not weighed in on this thread?

So far as I know the Danfoss compressors for marine fridges have only one
service port on the low side. When new it is sealed with a cap and black
gloop. Remove the gloop and the cap and you find an R34a-specific snap
coupling which mates to your vacuuum pump or charging manifold. I managed
to
set things up without a manifold or guages using a fitting that allows me
to
inject refrigerant directly into the low side port. You can vent excess
there
too with an Allen wrench pushing on the valve. Mine has been running
flawlessly (knock, knock) since I evacuated it and carefully injected
refrigerant using the frost line as a guide.


The gloop is a shrink-wrap. I had to slice it and peel it back from the R12
(!!) fitting on the high side when the factory installation charge was a bit
high (very careful about making up the joints, avoiding the factory-presumed
losses during that process) to vent it.

As Richard pointed out, there's a separate tap on the top left of the
compressor. VecoNA, the US distributor for Frigoboat, tells me that's ok to
use as a service port. I sliced that and removed the cap, only to find that
it was an R12 male, also.

Bob Williams, of SALT Service in Marathon, my vendor on installation (my own
box and installation), presumes there should be a low-side service port, but
visual (with a mirror, as it's under a low shelf with lots of stuff I'd have
to remove to be able to actually stick my head under there) and tactile
inspection shows the low side to not have a service port.

Perhaps the later versions have 134a taps; mine doesn't. I'm reluctant to
use the type of adapter Neal showed in his pic due to the inability to purge
the supply line. The slightest bit of moisture into the system can lead to
ice later; the folks I've been talking to, after they (all) reiterated that
nobody should try to do this on their own but having been convinced that
I'll do it, merely cautioned that the lines be fully purged. With an open
end, such as an R12 hose, vs the 134a air-hose type of snap-on, you just
open the valve a crack, let a bit out, and then close to a trickle while you
attach the cap before opening again to supply.

I've been able to find an adapter for the pump end which would convert a 12
pump to 134, but it doesn't have a Schrader depressor in them, preventing
use on the compressor. I'm hopeful of finding the same in 134-to-12, and
buy a 12 hose, but haven't yet, other than online, which will involve
shipping delay. My preference actually would be to have a hose fabricated,
but the only game in town is on vacation; I'd have to go either to Stuart or
Vero, assuming that hosemakers in one of those actually can do it. (My only
hose makeup experience was to make a new propane hose; I don't know if
they'd have the ends for AC/refrigeration...)

L8R, y'all

Skip, keeping a sharp eye on Emily - What are you doing about that, Neal?...


--
Morgan 461 #2
SV Flying Pig KI4MPC
See our galleries at www.justpickone.org/skip/gallery !
Follow us at http://groups.yahoo.com/group/TheFlyingPigLog
and/or http://groups.google.com/group/flyingpiglog

"And then again, when you sit at the helm of your little ship on a
clear night, and gaze at the countless stars overhead, and realize that you
are quite alone on a wide, wide sea, it is apt to occur to you that in the
general scheme of things you are merely an insignificant speck on the
surface of the ocean; and are not nearly so important or as self-sufficient
as you thought you were. Which is an exceedingly wholesome thought, and one
that may effect a permanent change in your deportment that will be greatly
appreciated by your friends."- James S. Pitkin

On 8/1/2011 7:27 AM, Richard Kollmann wrote:
Troubleshooting 12/24 volt Danfoss BD compressors.
If compressor runs continuously with less than desirable or no cooling
there is a refrigerant flow problem or loss of refrigerant or poor
condenser cooling. If at least 90% of evaporator’s surface area is


Lots of erudition, and I didn't read all, but did anyone mention the size of
whatever hole supplies cooling air to the refrigerator? I had same problem as
you when we got our trawler. Looked and the hole to the outside was 4 sq.
inches. Enlarged that and the problem went away.

gm

Plot thickenings...

My vendor has confirmed that the open port (well, not connected to anything)
on the top of the compressor is suitable to use for low-side connection...

After 2 days on the phone and the internet, I was able to obtain an R12 hose
and an adapter to put it on 134a taps locally (the adapter was the
challenge - widely available on line, but hen's teeth locally).

Imagine my surprise when I went to connect the 6CFM vacuum that I'd borrowed
to my gauges set that it was an R12 fitting! So, I have no means of having
a gauge on it, but I am reasonably sure it is doing the job with the
directly connected vac hose. I turned on the vac before making the
connection to the stub on the top of the compressor to assure no possible
intake contamination.

As I write, it's finishing the 12-hour evacuation. I'll leave the vac
running as I unhook the line from the compressor to insure no contamination
from there.

Then I'll put on my adapter and purge the line with a second or so of blast,
shut it down and then open a trickle to insure nothing but 134a in the hose
while I connect it.

The manual suggests a 5-second charge initially. My intent is to leave the
hose and can connected, but shut, after that initial blast, and run the
compressor. If the plate isn't fully frosted, I'll turn off the compressor,
wait for equalization, and then introduce a second or so a time, rinse,
repeat, until the exit line is slightly frosted outside the box. Once that
happens, I'll let it run for a while to make sure that's as far as it gets.
Then I'll shut it down, let it equalize, and vent from the high side (as the
vendor instructed me during our initial use, when the line was frozen for a
few inches) a spritz at a time until the frost recedes to the bulkhead, and,
again, let it run for a while. If all is stable, I'll unhook.

My vendor sez to look for 5psi on the suction side while it's running. I'm
assuming I'd connect my 134a hose through the feed on the gauge set, thence
to the adapted R12 line to the stub, with the high side gauge closed, and
the suction line feed dead-ended (connected to the 134-style snap-on so no
contamination from a closed line), then open the closed-loop suction gauge
which would (?) see the pressure from the feed line series.

I'll acquire a much smaller pump for my own and should we ever have to face
this again, I'll have a proper suction reading as the new pumps will have
the 134a nipple.

So, I'm about to commence recharging. I'll post the results here, but
expect something similar to Vic's experience, in the end.

L8R

Skip

--
Morgan 461 #2
SV Flying Pig KI4MPC
See our galleries at www.justpickone.org/skip/gallery !
Follow us at http://groups.yahoo.com/group/TheFlyingPigLog
and/or http://groups.google.com/group/flyingpiglog

"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore.
Dream. Discover." - Mark Twain

On Fri, 5 Aug 2011 09:19:28 -0400, "Flying Pig"
wrote:



So, I'm about to commence recharging. I'll post the results here, but
expect something similar to Vic's experience, in the end.


Not sure which "experience" you mean.
But to clarify my experience, it's not extensive and only involves
fixing maybe 6 or 7 auto A/C's.
When an A/C stops putting out cold air I first assume a leak of
refrigerant.
The gauge set confirms that.
So far every time with R134a.
In the old days of R-12 I didn't have a gauge set and just injected
in R-12 until it blew cold.
If it lasted less than a summer I replaced the compressor.
No evacuation, just replace the compressor and charge with R-12.
Did that twice with 100% success..
R134a leaks faster - smaller molecules than R-12.
With the R134a I've always had a gauge set.
But I've found that published exact high and low side pressures are
somewhat meaningless.
Pressures can easily be off 10 psi on the low, and 20 on the high side
and the system works fine.
That might indicate something on some systems, but it never told me
anything on the automotive systems I've fixed.
The gauge set makes you feel like a "pro" and is real handy for the
manifold.
I've found that if you just add the specified weight of refrigerant
you're probably there.
I stop injecting after the weight spec is met.
Even that's not exact. For example my Chevy Lumina calls for 34
ounces. The cans I use are 12 Ounces.
So on the 3rd can I'm guessing.
What I do is use a temp probe in the vent, make sure the system has
stabilized to the lowest temp, and after about half of the last can
inject in 15 second intervals, watching the temp.
When it doesn't change I stop. But I always end up closer to 36
ounces than 34. I don't fret about that.
Likewise, before I bought a good evac pump, I didn't always bother
with evacuating either. Used an air-operated vac pump a few times
but they don't pump down as needed.
Never noticed anything untoward, but auto A/C's don't have the long
lifetimes expected of boat and home A/C's.
Cars die pretty quickly, especially when they're 6-10 years old when
you buy them, which is what I do.
So far none of my A/C fixes have gone more than 6-7 years before I
junked the car/van.
The main advice I have is to refill with a dye.
If you leaked the refrigerant you need to find the leak.
I do maintain one car with 134a that just needs a can added every
couple years, but that's the only one I've seen like that.
And I don't expect to have that car much longer.
All the others have lost their charge much more quickly so I've
learned to just put the dye in and find the leak.
For me it's usually been compressor seals. One time dryer o-rings
that weren't rated for R134a, and twice condensers.
Luckily no evaporators.
From your descriptions, unlike a car, the parts that might leak are
hard to get at, and the system is different than an auto's.
Bottom line is R134a dye and a good UV light has *always* worked
for me to get at the heart of the problem.
But I've had it easy, and can't tell what you face from here.
Good luck and keep us posted!

--Vic

"Vic Smith" wrote in message
...
On Fri, 5 Aug 2011 09:19:28 -0400, "Flying Pig"
wrote:



So, I'm about to commence recharging. I'll post the results here, but
expect something similar to Vic's experience, in the end.


Not sure which "experience" you mean. (clip)

My apologies. It must have been in some other venue such as the Morgan or
Liveaboard lists, or I dreamed it. I'd thought you'd posted that you'd done
essentially what I'll be doing next, feeling for frost or ice on the exit
line, and either adding slightly or spritzing out for slight overcharge.

As I type, the freezer's at 26 or a tenth higher, and there's a TINY (2")
amount of ice in the return line insulation. Until it gets down to temp
(8°), I'll not worry about it. So far, very good, however. No oil at the
high pressure line - the replacement of the O-ring was a non-event. Piece of
cake. I'm assuming the system will be stabilized by tomorrow morning and I
can get on with redoing some very small spots on the inner sides of the
doors (dings) and GO SHOPPING!

Of course, I'll just turn the system back off, put my engine room back
together, and do my repairs before bringing it back to cold!

L8R

Skip



--
Morgan 461 #2
SV Flying Pig KI4MPC
See our galleries at www.justpickone.org/skip/gallery !
Follow us at http://groups.yahoo.com/group/TheFlyingPigLog
and/or http://groups.google.com/group/flyingpiglog

"Twenty years from now you will be more disappointed by the things you
didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore.
Dream. Discover." - Mark Twain

"Flying Pig" wrote in message
...
"Vic Smith" wrote in message
...
On Fri, 5 Aug 2011 09:19:28 -0400, "Flying Pig"
wrote:



So, I'm about to commence recharging. I'll post the results here, but
expect something similar to Vic's experience, in the end.


Not sure which "experience" you mean. (clip)

My apologies. It must have been in some other venue such as the Morgan or
Liveaboard lists, or I dreamed it. I'd thought you'd posted that you'd
done essentially what I'll be doing next, feeling for frost or ice on the
exit line, and either adding slightly or spritzing out for slight
overcharge.

As I type, the freezer's at 26 or a tenth higher, and there's a TINY (2")
amount of ice in the return line insulation. Until it gets down to temp
(8°), I'll not worry about it. So far, very good, however. No oil at the
high pressure line - the replacement of the O-ring was a non-event. Piece
of cake. I'm assuming the system will be stabilized by tomorrow morning
and I can get on with redoing some very small spots on the inner sides of
the doors (dings) and GO SHOPPING!

Of course, I'll just turn the system back off, put my engine room back
together, and do my repairs before bringing it back to cold!



I'm surprised you even bothered fixing it. After all, you could have gone to
a yard sale and gotten a kitchen refrigerator and just set it up under the
boat and plugged it into the shore power. A good used home refrigerator
would most likely last you the 10-12 years you're likely to remain at that
yard. LOL!


Wilbur Hubbard