Mr Cool 24K DIY Mini Split Install

[bodydamage]

I installed my Mr Cool 24K mini split this weekend. The house (1150sq/ft) we just bought (1yr ago) was built in 1977 and had baseboard heaters that we both hate, so we ripped them out. We have been using 120v self standing oil filled radiator type space heaters and although they work OK, they **** electricity, and take forever to heat the house. I've been around multiple mini splits before, so I'm familiar with their up/downs and general operation.

The install went just fine and after a bit of fiddling, it's up and running. I cannot for the life of me, figure out the best setting to get this think to act like it wants to regulate the heat. It warms the main area of the house up, but no matter what setting we put it on, it wont shut off (compressor or fan). It doesn't keep climbing, it just doesn't shut off. The more I think about it, the more I think this may be the inverter function. I have a couple more questions for those of you that have some experience with these things.

The thermostat. Where is the thermostat? Is it in the remote control, or in the unit? Could the remote batteries being ****, or the remote being too far from the unit be causing it to not cycle correctly?

The fan. When it's set to auto (the fan, not the unit), it just doesn't seem to work correctly. Last night I set the remote to 74, heat, fan on high and placed it on the piano right next to a digital thermometer, directly across the room (25ft maybe) from the unit. This morning, the thermometer said it was 73.5. No problem, Ill take it. The night before, with the fan on auto, it was like 66 when I woke up. Once I turned the fan up a but an turned the temp up, everything got warmer. Is the auto fan, really not auto?

Mode settings. What exactly does auto do? When I set it to auto and, let's say 74, it doesn't keep it there. It's all over the charts as to what it wants to do, fan on high, blowing cold, etc. Heat and cool make sense obviously, but auto isn't as apparent to me.

Lineset. I have 16ft of lineset to manage outside. Someone mentioned horizontally coiling vs vertically coiling due to lubrication issues. Can someone expound on that with maybe some pictures please?

Yes, I've read the manuals. They are very poorly written and not very informative. Here's a pic from inside. (yes, I'm aware that my 40yo linoleum is awesome)

 

[DHCrocks]

just a guess, but probably with it in auto the fan slows down as the temp gets closer to the target so its not pushing hard enough to distribute it throughout the room. so locally in the area the temp is correct. but on the far side of the room it will not be. you need to move the air around so it circulates and more evenly disburses. try using a fan to move air throughout the room and you will get more even temperatures.

 

[bodydamage]

We are going to install a ceiling fan. My wife has switched the fan to auto, and it has kept the house at a constant 71 all day with the unit set at 74. My fear it that the unit is running full blast trying to reach 74 and just not getting there. Hopefully the temp is on the unit and not on the remote.

 

[justinjoyal]

Your house must have REALLY bad insulation if you need 24kbtu for 1150 sq ft. Unless it's indeed the case, you're going to have humidity problems this summer when using A/C.


Now to your concerns:

The temp sensor is in the return section of the air handler.

A few degrees difference between set temp and actual temp is normal (to a certain extent.)

Keep the fan to Auto on Heat mode (forget about the auto switch-over mode on a mini-split, it *****.)

The inverter system will keep the unit running most of the time, at a reduced speed. This is what inverters do. Energy savings occur because of reduced capacity and cutting back on on-off cycling. So it's normal for it to never completly turn off.

 

[bodydamage]

justinroyal, thanks for the reply. We wont be using the AC in the summer, expect for very rare occasions. We live right on the water, and it hardly ever gets warm enough for AC here. I mainly bought it for the heat functionality.

So, the temp sensor is in the unit? That means the placement of the remote doesn't matter. Perfect, thanks.

We'll set the fan to auto and leave it to heat and see what we get for a few days, and report back.

 

[TTTTTT]

Did you do the lineset evacuate and charge or did you get someone in. If you did it yourself how did it go.
Thx

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[bodydamage]

It was the DIY, so it came with pre-charged linesets. No drama. Hooked 'em up and bammo, off she runs.

 

[TTTTTT]

It was the DIY, so it came with pre-charged linesets. No drama. Hooked 'em up and bammo, off she runs.

No pressure test for leaks or evac? No issues? Wow Did the manual instruct it that way. Would love to do the same but I have some reservations especially in the long run. Thx

 

[bodydamage]

No pressure test for leaks or evac? No issues? Wow Did the manual instruct it that way. Would love to do the same but I have some reservations especially in the long run. Thx

Yup, that's exactly how the manual said to do it. The unit is charged and the lines are under vacuum. As soon as you hook them together and open the valve on the unit, it charges the lines, and you are good to go. Will it last 10yrs? Dunno. It's warrantied for 7.

FYI, the fan has been set to medium and the temp has been set to 72 or 73, and the house has been a perfect 72 for the past few days. Ahh, nice.

Here's a link to the manual if you want to check it out. Line connection starts in section 6, page 23.
http://mrcool.com/documentation/mrcool-diy-2nd-gen-installation-manual/

 

[TTTTTT]

Thx for the update, much appreciated. Glad it worked out well for you.

 

[sgiss]

If is is the same as the 12k unit, you can set the "follow me" function on the remote. Then the temp sensor is in the remote. You can set the remote at "sitting level" and that will avoid the problem of the temperature at the unit (near the ceiling or where ever you put it) being different than the temp you experience at sitting level. In my house that is easily 5 degrees and various throughout the day. The manual is awful.

 

[justinjoyal]

If is is the same as the 12k unit, you can set the "follow me" function on the remote. Then the temp sensor is in the remote. You can set the remote at "sitting level" and that will avoid the problem of the temperature at the unit (near the ceiling or where ever you put it) being different than the temp you experience at sitting level. In my house that is easily 5 degrees and various throughout the day. The manual is awful.

Some units indeed have such feature. It doesnt always work well but you can always try it.

 

[bodydamage]

It does have the following me feature, but the manual isn't exactly clear on what it does. As an aside, my power company approved my rebate today. My total out of pocket cost on this guy is going to be around $350. It works really well so far.

 

[yeldogt]

The units do run most of the time -- at least mine always have. Mine have had external temp sensors ... they only went off if the outside temp was close to the inside. Otherwise they ramped up and down depending on the input temp desired.

 

[Klamnops]

Hi I'm look to get a DIY Mr cool for my house and deciding between a 18,000 or 24,000 btu model. Does your unit keep your bedrooms cool as well. The main level in my house is 880 sqft.

 

[eddieK]

It was the DIY, so it came with pre-charged linesets. No drama. Hooked 'em up and bammo, off she runs.

If you did not evacuate this...you have non condensibles in the system. This will severely shorten the life of the system, promise. The air that is trapped in there is moisture, that moisture mixing with the oil degrades it.

 

[mike93lx]

If you did not evacuate this...you have non condensibles in the system. This will severely shorten the life of the system, promise. The air that is trapped in there is moisture, that moisture mixing with the oil degrades it.

That's how the precharged units are designed to work. Quick connects, no evac needed.

 

[eddieK]

That's how the precharged units are designed to work. Quick connects, no evac needed.

There are noncondensibles in that system. No matter how they designed it. Refrigeration is refrigeration. I promise you this will seriously shorten the life span...and unique to these systems (mini splits) they are essentially disposable. In a short time (usually 3 years) you have no option but complete system replacement if there is a failure in major components.

Had a customer that damaged their air handler...4 years old. Had no options for air handler replacement, because there was no air handler that could "talk" with condensing unit.

I had one low tier brand's tech support tell me there are NO field diagnostics for their equipment. Comfortstar brand.

Only the major brands even have compressor replacement options and that is inconsistent depends on many factors, especially luck.

 

[Fixin'Stuff]

There are noncondensibles in that system. No matter how they designed it. Refrigeration is refrigeration. I promise you this will seriously shorten the life span...and unique to these systems (mini splits) they are essentially disposable. In a short time (usually 3 years) you have no option but complete system replacement if there is a failure in major components.

You might want to read up on the Mr. Cool DIY Series. It doesn't work like you assume it does. The entire system, including the linesets, is vacuumed and pre-charged with refrigerant before it leaves the factory. It is quite literally a plug and play system. They do the critical stuff at the factory. Set the units in place, connect the lines, add power, be cool. They even offer a 7 year warranty on self-installs.

Here's a quick install guide that shows just how easy it is:

 

[eddieK]

You might want to read up on the Mr. Cool DIY Series. It doesn't work like you assume it does. The entire system, including the linesets, is vacuumed and pre-charged with refrigerant before it leaves the factory. It is quite literally a plug and play system. They do the critical stuff at the factory. Set the units in place, connect the lines, add power, be cool. They even offer a 7 year warranty on self-installs.

Here's a quick install guide that shows just how easy it is:

If the liquid and suction connections were made (connected) by anyone...and before the valves are opened the air in those lines was not removed by evacuating to 500 microns minimum...there is now non condensibles in that system. Another problem I see is there is no way to nitrogen pressure test the system. Bubbles will only tell you it is not leaking when the pressure is stabilized, not when the pressure on the high side hits 400 PSI...then the only way you know you have a leak is because you no longer have cooling or heating...in some cases if this takes too long to discover you just severely damaged the compressor windings.

If those lines are pre evacuated - there is no way to test it without losing the vacuum and drawing in moisture, this becomes a hoping for the best scenario.


No way there is not...no matter what the foreign manufacturer attempts to tell you in those very poorly translated instructions. The only way to not evacuate and not leave condesibles is to vent the system...purge it...which is ILLEGAL, you cannot purposefully vent refrigerant into the atmosphere.

That warranty is for PARTS only. not the refrigerant or the labor or the liquid line filter drier needed at the repair event.

Easy does not always (in fact it usually doesn't) mean correct.

Best of luck to you. I probably know too much and have dealt with this for too long and seen too many DYI failures in critically charged refrigerant systems in my 40 years in the trade.

 

[yeldogt]

There are noncondensibles in that system. No matter how they designed it. Refrigeration is refrigeration. I promise you this will seriously shorten the life span...and unique to these systems (mini splits) they are essentially disposable. In a short time (usually 3 years) you have no option but complete system replacement if there is a failure in major components.

Had a customer that damaged their air handler...4 years old. Had no options for air handler replacement, because there was no air handler that could "talk" with condensing unit.

I had one low tier brand's tech support tell me there are NO field diagnostics for their equipment. Comfortstar brand.

Only the major brands even have compressor replacement options and that is inconsistent depends on many factors, especially luck.

The line set is connected to the head unit and the whole thing is evacuated through the quick connect fitting. The condenser has the fittings installed -- so I guess that inch or so is not evacuated.

In Asia I have seen these installed with sealed flex lines .. I have also seen them (many) ... just connected ... it's common to see them installed that way. Not saying it's the best way -- in many cases .. it's the only way.

 

[eddieK]

The line set is connected to the head unit and the whole thing is evacuated through the quick connect fitting. The condenser has the fittings installed -- so I guess that inch or so is not evacuated.

In Asia I have seen these installed with sealed flex lines .. I have also seen them (many) ... just connected ... it's common to see them installed that way. Not saying it's the best way -- in many cases .. it's the only way.

Meh - As the saying goes, you get what you pay for.

Have any of these DYI units been around 10 - 15 yrs? If so, I would love to see the fail rates

 

[yeldogt]

Meh - As the saying goes, you get what you pay for.

Have any of these DYI units been around 10 - 15 yrs? If so, I would love to see the fail rates

If the line have been evaluated -- what's the problem?

 

[mike93lx]

Meh - As the saying goes, you get what you pay for.

Have any of these DYI units been around 10 - 15 yrs? If so, I would love to see the fail rates

Exactly. I paid under $2k for an inverter drive 24k btu and installed it myself. Far cry from the quotes i got at $7k+. Currently on year 3 and it works as well as the day i installed it. If it lasts 1/2 as long, i'd still be ecstatic.

 

[eddieK]

If the line have been evaluated -- what's the problem?

They are not evacuated(the lines may be before peircing, but when connecting you are trapping air....ANY air turns into moisture. All that needs to be done after connection is a 400 PSI nitrogen pressure test and an evac down to 500 microns. No way to tell IF it will leak without a pressure test.

The only way to find out without doing this is system ops failure, now you have created damage.

There is no way to tell (outside of hope) that the system has zero moisture unless you pull a vacuum.

It's like purity, the water ain't pure if there is just one drop of oil in it.

The reason to do this right is.... it (moisture - non condensibles)does destroy compressor windings. The air/moisture, mixed with system oil becomes an acid eventually.

This is a hope situation. You are not paying a small amount now and hoping to not pay dearly later.

 

[handymancanfixit]

They are not evacuated(the lines may be before peircing, but when connecting you are trapping air....ANY air turns into moisture. All that needs to be done after connection is a 400 PSI nitrogen pressure test and an evac down to 500 microns. No way to tell IF it will leak without a pressure test.

The only way to find out without doing this is system ops failure, now you have created damage.

There is no way to tell (outside of hope) that the system has zero moisture unless you pull a vacuum.

It's like purity, the water ain't pure if there is just one drop of oil in it.

The reason to do this right is.... it (moisture - non condensibles)does destroy compressor windings. The air/moisture, mixed with system oil becomes an acid eventually.

This is a hope situation. You are not paying a small amount now and hoping to not pay dearly later.

You seem to be missing the point of these DIY units. They are low priced units that can be installed by a DIYer with half a brain, no professional installer needed, no expensive specialty tools required.

They are designed to be installed without being evacuated at installation. If it lasts through the warranty period, I will be satisfied with my purchase and successful installation. I don't give a rats A$$ if a few microns of moisture get trapped in the system. The system will outlast the effects of those moisture microns and die of something else long before.

I feel confident that anyone who installs one of these DIY units would feel the same way.

 

[12000peak]

Installed the MrCool 24K ...got mine from Ingrams water and air....delivered about 4 days using XPO logistics (to SoCal) and the deliver guy help me move into my house....now my question is....is it normal to have frost on the pipe?...I double check and there is NO leak on both pipes.

 

[PoorOwner]

Installed the MrCool 24K ...got mine from Ingrams water and air....delivered about 4 days using XPO logistics (to SoCal) and the deliver guy help me move into my house....now my question is....is it normal to have frost on the pipe?...I double check and there is NO leak on both pipes.

I don't know about the frost but you didn't coil it with the drain like that did you?

 

[12000peak]

this is the back view...the drain line is aim to the ground.

 

[TTTTTT]

If the drain line is bundled with the other lines like most you cannot have it coiled like you have done. Definitely cause major issues.

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[justinjoyal]

I don't see any problem with the drain line.

 

[TTTTTT]

Is it not looped on the inside pic or is it not bundled on the lineset and runs straight down.

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[justinjoyal]

A freezing suction line could indicate liquid r410 flooding the compressor. Can be caused by low indoor load or system overcharge.

Does the indoor coil look fine (meaning not iced up) ? That, on the other hand, could indicate low charge.

Ps: also make sure the suction line is not kinked.

 

[justinjoyal]

Is it not looped on the inside pic or is it not bundled on the lineset and runs straight down.

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It doesnt seem to be looped on the inside and it runs straight down on the outside.

Are both pipes insulated together or separately ?

 

[TTTTTT]

If the drain line is separate then should be no problem. Thought it looked bundled and looped.

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[redman333]

Hey found this while looking for installs and trying to size my garage unit. I want to have a dual head unit. I have a 2 story garage. 600sqft downstairs in the workshop and 450sqft upstairs in the guest room. Im thinking a 18k unit will be enough am I wrong on thinking this?