How to Pump Down a Sanyo M/S without a main board?

Xringer · 08-25-16, 04:20 PM

My main board on the den Sanyo is toast. So, how can I pump down the lineset?
To move all the R410a in the lineset, into the outdoor unit, I need to run that compressor.

It seems like all I have to do, is swap out the main board on the 'working' Sanyo (living room)..
But, I'm reluctant to risk my good main board, in an ODU that might zap it..
However, if the living room Sanyo will power up and run, without it's compressor plugged in, (lines U,V & W)
maybe I can run (50' extension cord) the three motor lines from good unit, to the bad unit's compressor??
If it didn't want to run, maybe T-Test mode would force it to work?

Is this idea dumb or just crazy?
Comments please:

I really don't want to blow up my old living room Sanyo, since it's been
keeping us cool all summer.. Yes, it does cool the whole house..

But, if I have to transfer the main board, I will take that chance..
I should be able to buy some new Gree systems before we melt here!
It's slowly getting cooler, but not that fast..

Xringer · 08-27-16, 11:51 AM

I've been trying to contact my HVAC buddy from work..
But, I've been out for about 9 years! He might retired too!
May have to use Craigslist. Which I would love to avoid..

I wonder how well (heat gun) heating the indoor HX and cooling down the outdoor HX with a CO2 fire extinguisher would work?
Or maybe just freezing the outdoor HX and compressor would suck in any liquid.?.
Using the built-in Pump-down is the best way.. It even puts a little vacuum into the lineset. Nothing at all leaks..

jeff5may · 08-30-16, 07:38 PM

I would definitely try to use the unit that works to operate the compressor in the one that doesn't. As long as the compressor ohms out ok, there is little chance of burning up the working control board. The long extension cord will actually act as a ballast, smoothing out spikes and limiting current draw. As long as it is heavy enough to conduct normal operating current, it will do the job for a short while.

Running the fan in the outdoor unit, or otherwise cooling the condenser, will be needed as well. The arriving gas could pop the plumbing if it isn't cooled quickly and sufficiently. In a pinch, you could probably just spray some water on the coil to keep it cool while pumping the charge.

Xringer · 08-30-16, 08:46 PM

I was wondering about things that could go wrong, last night. This morning, we decided to swap out the main board..
It didn't take very long. I started early before it got too hot.
Got the good board into the den unit, ran it a few minutes, and pumped it down until I saw the pressure go below 14 PSI.
Had a slight vacuum hiss when I pulled the lineset off..

Returned the good board back in the living room unit and it's been keeping us cool & dry this evening..
(I noticed that my good board didn't have near enough heat sink compound. Added some).
I'll stick the bad board back inside the den outdoor unit.. Now in the garage.. Again.
If I keep the working Sanyo, I'll save the broken system for spares..
But, I may be ordering another -20F Gree, soon.. If this new 18k looks real good..
If we end up with two Grees at some point, we might be getting rid of both Sanyos. My wife is nuts about that idea..

08-25-16, 04:20 PM	#1
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	How to Pump Down a Sanyo M/S without a main board? My main board on the den Sanyo is toast. So, how can I pump down the lineset? To move all the R410a in the lineset, into the outdoor unit, I need to run that compressor. It seems like all I have to do, is swap out the main board on the 'working' Sanyo (living room).. But, I'm reluctant to risk my good main board, in an ODU that might zap it.. However, if the living room Sanyo will power up and run, without it's compressor plugged in, (lines U,V & W) maybe I can run (50' extension cord) the three motor lines from good unit, to the bad unit's compressor?? If it didn't want to run, maybe T-Test mode would force it to work? Is this idea dumb or just crazy? Comments please: I really don't want to blow up my old living room Sanyo, since it's been keeping us cool all summer.. Yes, it does cool the whole house.. But, if I have to transfer the main board, I will take that chance.. I should be able to buy some new Gree systems before we melt here! It's slowly getting cooler, but not that fast.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

08-27-16, 11:51 AM	#2
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I've been trying to contact my HVAC buddy from work.. But, I've been out for about 9 years! He might retired too! May have to use Craigslist. Which I would love to avoid.. I wonder how well (heat gun) heating the indoor HX and cooling down the outdoor HX with a CO2 fire extinguisher would work? Or maybe just freezing the outdoor HX and compressor would suck in any liquid.?. Using the built-in Pump-down is the best way.. It even puts a little vacuum into the lineset. Nothing at all leaks.. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

08-30-16, 08:46 PM	#4
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	All pumped down.. I was wondering about things that could go wrong, last night. This morning, we decided to swap out the main board.. It didn't take very long. I started early before it got too hot. Got the good board into the den unit, ran it a few minutes, and pumped it down until I saw the pressure go below 14 PSI. Had a slight vacuum hiss when I pulled the lineset off.. Returned the good board back in the living room unit and it's been keeping us cool & dry this evening.. (I noticed that my good board didn't have near enough heat sink compound. Added some). I'll stick the bad board back inside the den outdoor unit.. Now in the garage.. Again. If I keep the working Sanyo, I'll save the broken system for spares.. But, I may be ordering another -20F Gree, soon.. If this new 18k looks real good.. If we end up with two Grees at some point, we might be getting rid of both Sanyos. My wife is nuts about that idea.. Attached Thumbnails __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

08-30-16, 07:38 PM	#3
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,431 Thanks: 431 Thanked 619 Times in 517 Posts	I would definitely try to use the unit that works to operate the compressor in the one that doesn't. As long as the compressor ohms out ok, there is little chance of burning up the working control board. The long extension cord will actually act as a ballast, smoothing out spikes and limiting current draw. As long as it is heavy enough to conduct normal operating current, it will do the job for a short while. Running the fan in the outdoor unit, or otherwise cooling the condenser, will be needed as well. The arriving gas could pop the plumbing if it isn't cooled quickly and sufficiently. In a pinch, you could probably just spray some water on the coil to keep it cool while pumping the charge.