Sanyo 24KHS72 Mini-Split DIY REPAIR project

[Xringer]

I'll end this tale with a link to the install repaired unit project.
http://ecorenovator.org/forum/geothe...ct-2011-a.html

The repaired system has been working fine for over a month now.
I'll post back here again, if the repaired system fails..


Edit: 4/22/2013
It's now 18 months after the repaired until was re-installed in the Den.
It's still working fine. http://ecorenovator.org/forum/geothe...html#post29549

Edit: 10/13/2013
Still heating and cooling after 2 years

Edit: 3/31/2014
928 days. Or 2 years, 6 months, 16 days.
Spring? Nope, it's still winter and we are still running both Sanyos 24-7.
No problems seen, during the worse (coldest) winter we've had for many moons.


Edit: 6/10/2015
1333 days Or 3 years, 7 months, 25 days

Fan motor on the indoor unit is starting to make a little whining noise, like the old one in the living room.
The winter of 2014-15 was the coldest with the deepest snow of any winter I can recall.
Both systems are still working normally. The silver-soldering is holding!

[Xringer]

We got a power surge during a snow storm this winter 2015-2016, that killed the main board.
Not much hope of repairing it, without a schematic - circuit diagram.
So the repaired Den AC only lasted about 4.5 years.

[jeff5may]

Not bad for a freebie outdoor unit refurbish. Have you finally thrown the towel in on the control board? It's kind of ironic that your repair held up while more of Sanyosonic's work failed. Hopefully the other unit will last ten years like it should...

[Xringer]

I've been thinking of devoting another few hours of searching for a replacement board.
(I should have saved the links)..
But, I may have to use the tablet, since this display is starting to die..

[Xringer]

Originally Posted by Xringer

At the end of today's testing, I decided to try the Sanyo Pump-Down trick..



So, I shut off the small Liquid tube valve, hit the toggle switch and watched
the pressure drop as the R410A in the little test loop was sucked inside.
When the gauge neared 10 PSI, I started closing the large Suction line valve.
It was open a full 4 turns! By the time I got it closed, the pressure was going negative!
I quickly hit the switch and removed the manifold hose.. It didn't hiss at all..
When I removed the cut-off from the Schrader service port, no hiss..
I think the little test line-set might have a little vacuum in it!!
(edit removed extra text)

I think this pump-down procedure has a problem. Starting with Step 1 above.
When you connect up your manifold gauges, there is air inside the hoses.
When the pump-down is in the last stage, (step 4) the compressor creates
negative pressure (less than 14psi) inside the hoses and sucks that air into the M/S..

Solutions:
1. After connecting the gauge manifold, hold the manifold up high (R410A is heavier than air),
wait a few minutes for the air to rise to the top, and quickly bleed the air off using the manifold's valves.

2. Use an adapter with a cut-off valve on the service port.


Crack the cut-off valve a little bit, to bleed out any air trapped inside it.

With the cut-off closed. Attach a vacuum pump to the middle of your gauge set.

Pull a good vacuum on the gauge set, and the hose going to the service port.
(If you can't get a good vac, your service port adapter cut-off may be leaking a little).

After getting a vac, shut off the vac hose to isolate the vac pump, turn the pump off.

Now the air is gone, you can open the service port cut-off valve,
and see the pressure on the low side gauge shoot up to T/P psi for R410A..

Now, the rest the process can be done, without contaminating your R410A with air from the hose and manifold..


Is the second solution over-kill? It doesn't release global warming gas.
Or, is the 1st solution just as good, and doesn't harm the ozone layer..