The neverending mini split saga

[Tracs]

I have been fighting my Perfect Aire R410 18K mini split for 3 years. I have other threads on it but will summarize.

Originally installed in the summer of 2017 into my 24x30 garage by my Unlce who owns a sheetmetal shop. He is not a HVAC tech but has the equipment. It worked great that summer keeping the garage cool, and even lowering the temperature further when needed. You could drive a hot car into the garage and a short while later the garage temperature was back to the set point.

Life was great...

Until the winter of 2019. It was almost to the day now. I was using the mini split in heat mode and it was working fine. Until a heavy snowfall plugged up the outdoor unit. I hadn't been paying attention and the excess snow on the coils melted and turned the unit into a block of ice. The cooling fan blade was half frozen into ice.

I tarped the unit and defrosted it with a construction heater. I did not use the unit again until the spring/summer when needed for cooling. The cooling fan motor had burned up so it needed replacing. I replaced it and the unit was working again.

That summer of 2019 it didn't cool as well as it used to. I lived through it though. In the fall I was using it as a heat source again but the coils on the outdoor unit would frost up pretty good.

This continued through 2020 also.

This past summer 2021 I had my Uncle come over and check the refrigerant charge. Sure enough it was slightly low, around 95-100 PSI. The service manual calls for 117-120 PSI at the temperatures we had.

So he brings over his canister of R410 and hooks it up and adds some refrigerant, going off operating pressures stated in the service manual.

Right off the bat I knew something wasn't right. He had his cylinder of R410 with the valve facing up. I asked him if the tank should have the valve on the bottom while charging. He said it didn't matter. I had researched and everything I read said the tank should be upside down.

Not wanting to make him mad, (since it took months to get him over) I let him do his thing. This summer 2021 the cooling worked good again. Come fall using it as a heat source the condenser coils were icing up again.

So now I have a system that I think was improperly charged with R410. Am I correct in assuming It was charged with the gas out of the tank instead of the refrigerant?

Can the system be corrected without recovering all the refrigerant and recharging?

TL;DR - Mini split froze, then thawed, then recharged with R410 tank with valve right side up. What are the options?

 

[fitter30]

Unit needs to go into a defrost mode in heating. Don't know that brand u have need compleate model number. Most defrost mode is by temperature by a sensor on the outside face of condenser coil. If u have the service manual look up defrost mode.
All mini split units are critical charge on name plate tells what the basic charge is and the install manual tell up to so many feet of line. Only ight way to charge a mini reclaim, evacuate and weigh charge in.

 

[dave*99]

I have been fighting my Perfect Aire R410 18K mini split for 3 years. I have other threads on it but will summarize.

Originally installed in the summer of 2017 into my 24x30 garage by my Unlce who owns a sheetmetal shop. He is not a HVAC tech but has the equipment. It worked great that summer keeping the garage cool, and even lowering the temperature further when needed. You could drive a hot car into the garage and a short while later the garage temperature was back to the set point.

Life was great...

Until the winter of 2019. It was almost to the day now. I was using the mini split in heat mode and it was working fine. Until a heavy snowfall plugged up the outdoor unit. I hadn't been paying attention and the excess snow on the coils melted and turned the unit into a block of ice. The cooling fan blade was half frozen into ice.

I tarped the unit and defrosted it with a construction heater. I did not use the unit again until the spring/summer when needed for cooling. The cooling fan motor had burned up so it needed replacing. I replaced it and the unit was working again.

That summer of 2019 it didn't cool as well as it used to. I lived through it though. In the fall I was using it as a heat source again but the coils on the outdoor unit would frost up pretty good.

This continued through 2020 also.

This past summer 2021 I had my Uncle come over and check the refrigerant charge. Sure enough it was slightly low, around 95-100 PSI. The service manual calls for 117-120 PSI at the temperatures we had.

So he brings over his canister of R410 and hooks it up and adds some refrigerant, going off operating pressures stated in the service manual.

Right off the bat I knew something wasn't right. He had his cylinder of R410 with the valve facing up. I asked him if the tank should have the valve on the bottom while charging. He said it didn't matter. I had researched and everything I read said the tank should be upside down.

Not wanting to make him mad, (since it took months to get him over) I let him do his thing. This summer 2021 the cooling worked good again. Come fall using it as a heat source the condenser coils were icing up again.

So now I have a system that I think was improperly charged with R410. Am I correct in assuming It was charged with the gas out of the tank instead of the refrigerant?

Can the system be corrected without recovering all the refrigerant and recharging?

TL;DR - Mini split froze, then thawed, then recharged with R410 tank with valve right side up. What are the options?

The gas in the tank is refrigerant. There are no "propellants" in that tank like you would have with something like spray paint.

 

[PoorUB]

R410 needs to be charged as a liquid, generally the tank needs to be upside down. I would have someone reclaim it, put a good vacuum on the system and recharge it properly, and someone other than your uncle.

 

[brianh]

Well if it needed more refrigerant regardless if done correctly or not it would point to a leak. Icing is normal as long as it periodically goes through a defrost cycle, I get the most icing when the temperature is just above or at freezing with the air at a high moisture level. I put a roof over my units and have them elevated off the ground to keep snow and freezing rain off.

 

[Jackfre]

I’m with PoorUB on this one. It does sound like you have a leak. reclaim the refrigerant, pressurize with Nitrogen, identify/repair the leak(s) and charge it. 410a must charge ith liquid and the cylinder must be upside down. Elevate the condensing unit. You froze up the fan because the unit was unable to drain the condensate created in the defrost mode. With the unit pad mounted the ice builds internally and you know what happens. If the roof is shedding its contents on the condensing unit you need to deal with that too.

 

[Tracs]

Does the system have to be reclaimed into a tank, or as per the service manual, can it be ran in the correct mode to draw all refrigerant into the unit? Then the lines can be charged with nitrogen and checked for leaks? Theoretically this would put the unit into the same situation as the original install.

Someone had mentioned about the exact model #. It is 2PAMSH18B-SZ0-17.7

 

[Syberia]

I'm guessing you have a leak in the outdoor coil. So pumping the refrigerant into the condenser, if it can be done, would be useless. Water expands when it freezes and if, as you say, the whole thing turned into a block of ice, it's quite possible something got tweaked/damaged.

 

[Tracs]

I'm guessing you have a leak in the outdoor coil. So pumping the refrigerant into the condenser, if it can be done, would be useless. Water expands when it freezes and if, as you say, the whole thing turned into a block of ice, it's quite possible something got tweaked/damaged.

As per the service manual it says the unit can be run in cooling mode with the 2-way valve closed and the 3-way open until the system reads 0.1MPa and that will draw the refrigerant into the outdoor unit then close the 3-way. But as you said with it freezing up there was probably damage.

I will have to wait until spring/summer to really have it investigated. I may just replace the unit with a nice inverter extreme cold weather unit. I have seen a few that will make heat down to -30 or more.

 

[RAB]

A few ways of doing this. You could use an electronic leak detector to sniff for a leak as is but it is very time consuming and without enough pressure small leaks can be very hard to find especially outdoors where wind can cary the gas away from the detector. I agree with the above posts that the ice could have damaged the outdoor unit casing a leak or other damage that may be causing your frosting issue. Faster way to rule out a leak is to recover the charge and hopefully your uncle weighed the gas in as he should have. Obviously you should have factory charge plus what he added, if not, how much is missing will give an indication to the size of the leak. If you have the full charge plus what was added you would only need to pull a vacuum and, after achieving 500 microns, isolate the pump and see if the microns increase which would indicate a hole. You also likely would have a hard time pulling 500 microns if you had a hole depending on size. As far as tank inverted or not, it really depends on if it had two valves (liquid and vapour). You should be charging 410 via liquid. If your tank only has one valve it should have been inverted as the gas will fractionalize and not have the proper performance characteristics. However, if he only put a small amount in I would not be overly concerned. Really it may be cheaper to just hire a certified technician unless you have acess to all the equipment and won’t make the whole thing worse. If you are successful at confirming the charge and leak (or not) you will still need to possibly fix the hole or figure out the other issue.

 

[theoldwizard1]

Does the system have to be reclaimed into a tank, or as per the service manual, can it be ran in the correct mode to draw all refrigerant into the unit? Then the lines can be charged with nitrogen and checked for leaks? Theoretically this would put the unit into the same situation as the original install.

This is exactly what I would do if I questioned the charge. Nitrogen may not be required if you have not lost a significant amount of charge. If needs to hold a very deep vacuum for at least 30 minutes.

 

[LS6 Tommy]

This is exactly what I would do if I questioned the charge. Nitrogen may not be required if you have not lost a significant amount of charge. If needs to hold a very deep vacuum for at least 30 minutes.

Vacuum CANNOT be used to leak check.

Tommy

 

[Tracs]

It will be at least 3 months before the weather remotely cooperates to even run the unit.

First order of business will be to measure the operating pressures to see if it has leaked any more.

I will have it checked for leaks. If the outdoor coil or unit was damaged from the freeze up, it would probably make more economical sense to replace the entire unit. It was only $1200 at the time and installed for free. If the condenser coil or such needs replaced I would think by the time the leak is found and repaired I would be half the cost of a newer/better unit. I would like to upgrade it to a Mitsubishi unit that makes heat down to -30 and or beyond depending on conditions as they say.

 

[theoldwizard1]

Vacuum CANNOT be used to leak check.

I agree it is not the best but if you don't have N2 available, it is better than nothing.

 

[LS6 Tommy]

I agree it is not the best but if you don't have N2 available, it is better than nothing.

I really can't argue that logic.

It's just that so many people say to forgo pressure testing and just "leak check" with a vacuum. I can't count the number of charge losses I've encountered over the years because of that thinking. A vacuum can and will hold a leak shut until the system is under pressure.

Tommy