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Old 09-15-11, 03:47 PM   #1
Xringer
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Default Sanyo 24KHS72 Mini-Split DIY REPAIR project

This Thread is about repairing a leaky outdoor unit..
See here for details: http://ecorenovator.org/forum/geothe...html#post13279

Foaming at the leak point.


There's the exact spot. (or maybe 4 mm to the right)..


CO2 feed rig. Hey, I got to use my fare tool !! IIRC it was AC Hacker that told
me how to control the flow rate of the inert gas required for brazing copper.
I just cracked the valve, so the bubble rate on the output side was very slow.
If the flow rate was too high, the pressure inside the tube would blow the
filler metal out of the hole, I was trying to patch..
I also want to thank the guys who told me CO2 could be used instead of Nitrogen.


Wet Wrapped. (Find the words, Back Here!). The Brown backgound is a sheet metal plate, to prevent heat damage.
I used absorbent cotton strips to protect the compressor (and other parts),
to keep the heat from traveling down the tube and melting stuff..


Getting ALL the air out. (Ran it like this for 30 minutes, before lighting the torch).


Messy stuff!! This area was starting to glow cherry red and the filler stick started melting. When it got really liquidy, I pulled back the flame. One of those metal Drops formed
on the bottom of the tube, the second it really started to flow. MAPP gas works okay!



Out of Nitrogen (too far to drive), so I filled it to 400 PSI with dry SCUBA air.
(Air has been leaking into the system for months anyways).

It held pressure very well. I checked the messy repair area with my stethoscope, and heard no hissing at all..
(I had used a crude listening tube to discover the location of the leak).
It held 400 PSI for an hour. I buttoned it up with 350 PSI, so I can go back
and check it next week..
I tie-wrapped the thermistor back on the tube, right above the compressor.

If the pressure holds, I guess the next step is to vacuum out the system..
I've never done one of these, (just line-sets) I wonder if there are any special precautions needed.?.

After it's all tested, it will need to be charged up with refrigerant..
Then, placed in long term storage (as a back-up), or put to use ASAP.?.

My two use-it choices are shown here:
http://ecorenovator.org/forum/geothe...html#post15381

Cheers,
Rich


Last edited by Xringer; 09-15-11 at 11:43 PM..
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Old 09-16-11, 07:10 AM   #2
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Nice job Xringer!
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Old 09-16-11, 07:40 AM   #3
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Very nice indeed! Have you made a decision on what you want to use it for yet?
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Old 09-16-11, 08:13 AM   #4
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I'm leaning towards buying another indoor unit and installing the new 'system' in the den.
(Where it can help out that poorly insulated room).

If for some reason, I can't get it to work in the den, a second indoor unit would give us a complete
set of spare parts for the existing main-house system. That could be very useful in the event of a lightning hit.

Plus, it would give us a spare remote control too. These things are hard to control without that remote.

Actually a single remote could control multiple systems, by setting the
indoor units to used their on-board thermistors.
(Instead of using the thermistor built into the remote controller)
Then, the remote would used for all other controlling functions as needed.
(Mostly Set points & operating modes).

Cheers,
Rich

Last edited by Xringer; 09-20-11 at 08:38 PM.. Reason: facts
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Old 09-16-11, 08:30 AM   #5
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Quote:
Originally Posted by S-F View Post
Nice job Xringer!
Thanks S-F, my wife is also proud of me..

It was a rainy day as you know, so bike riding was out of the question..
And my wife was out for a while. Without her Corolla blocking access,
I went into the unit to check clearances for the flame.
Could I do it, without melting things or setting the garage on fire?

There was a small access 'hole' for the torch between the other tubes,
and since it was still raining, I decided give it a try.
I hope it holds, or I will have to try again, using a longer heat-up.

I was pleased to see how quickly the area heated up, when removing
the thermistor tube. It only took a minute before it fell off.
I gave it about another minute to get more red hot and applied the filler stick.
It started melting onto the top within about 10 or 15 seconds.
Most of the heat/flame was coming in from a low angle,
so the bottom heated up first and area of the pin-hole warmed lastly.
I guess that's why the repair blob looks so bad..?.
I did not want to get so much heat that all of the molten filler would
get real thin and liquified, so it would just run off the tube and not
leave a layer on top of the pin-hole area.
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Old 09-16-11, 11:38 AM   #6
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Xringer,


Your braze flow is not ideal... not enough heat.

But the proof is in the pudding, and if it doesn't leak, it doesn't leak.

Hopefully it will stay that way.

Good luck with your project.

-AC_Hacker
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Old 09-16-11, 12:03 PM   #7
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I know! It looks terrible compared to soldering. But, there is a pretty large filler-metal 'drip'
hanging just under the area of the pin hole. That means it did get a bit runny..

In the center of the pin hole area, it got really fluid-like and that was enough for me.
I did not want all the filler-metal running off and under the tube, leaving only a thin layer of filler on top of the pin hole.

My theory is, the pin hole is So small, that the chance of filler-metal actually entering
the hole is very low. So, I wanted a thick layer of filler on top of the hole,
but a layer that is well bonded to the copper. Just wish it had been pretty..

If it doesn't hold pressure, I still have the repair kit on standby..

Last edited by Xringer; 09-16-11 at 12:05 PM..
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Old 09-17-11, 11:16 AM   #8
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Default How to test?

I'm not sure if there was any damage to the compressor when the failure occurred (Dec 2009),
the system lost it's R410A and a few ounces of oil and seemed to want to run, even with very little pressure..
Almost no pressure.. Did anything burn up inside the compressor??

So, how can I test this thing?? (Before investing in more hardware)..

When I was doing the repair, I noticed oil on the floor pan and inside the thermistor
wire insulation tube, that looked nice and clean, clear too..
Maybe even usable for a test.?. If there is enough left inside..


I have 28 oz of R410A. That's about 40% of the 4.3 pounds (69oz) needed, if used with a 20-30ft line set.

So, could I build a very short line-set/HX test set, using some copper tube
to sit a little coil in a bucket of water, while running in test mode?

I have the flare couplings, and would only need some copper tube.
♦ Refrigerant Piping Discharge (O/D Inches) : 1/4 (0.25")
♦ Refrigerant Piping Suction (O/D Inches) : 5/8 (0.625")

AND, some kind of copper coupling from 1/4 to 5/8..
If not available at HomeDepot, maybe a 5/8 copper cap and drill a 1/4"
hole in the side of the 5/8" tube and braze in the 1/4" tube?
(Maybe using CO2 flood)?

Am I missing anything?
Comments please.

Cheers,
Rich
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Old 09-19-11, 10:36 AM   #9
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This morning at 11:30 AM, the Sanyo air pressure reading was 340 PSI (after sitting for 93 hours).
Low Temperature last night was 40.3F, so a 10 PSI drop was not unexpected.

I'm going to declare 'Leak Repaired'!!
And head on over to HD and get some copper to build a lineset test rig.

14:00 Back from HD. Got 10 feet of good 1/4" copper. But the big stuff I wanted,
1/2 in. x 10 ft. Soft Copper Type L Coiled Pipe-LSC3010PS at The Home Depot
Actual inside diameter (in.) : 0.545
Actual outside diameter (in.) : 0.62
Assembled Depth (in.) : 120 in
Assembled Height (in.) : .625 in
Assembled Width (in.) : .625 in


Only turned out to have a 0.5" OD... So, that's $19.11 that I'm going to save.


The solution to this problem is to make my test loop out of 10'x 1/4" line.
I'll make an adapter using some regular old 1/2" (0.625 OD) Type 'L' copper pipe.
I'll braze a cap on it (cap will have a 1/4" hole) and flare the other end..

Last edited by Xringer; 09-19-11 at 01:20 PM..
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Old 09-19-11, 04:32 PM   #10
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Default More MAPP Gas!

I was letting a little CO2 into the 1/4" end as I was brazing the cap and pipe end.


Using the Flare tool on the 1/2" end too (actually 0.625")

I don't know what I'm doing, but the flares seem to be holding okay.

Finished product.


Only, I left a tiny void in the bottom of the 1/4" hole.. Had to go back and re-do it.
When using high gas flow to the torch, the copper heats up quickly.
The filler metal can actually melt really fast.
I'm starting to get the feel of how the melted filler moves and reacts to the heat level.

It seems like being a slow learner, isn't helped when you get old..

Anyways, the test loop is installed on the Sanyo and the system+loop is holding 400 PSI now.
This week (if things go my way), I will bleed down the system and start
making some vacuum checks.

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