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Old 08-29-2020, 07:28 PM   #1
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a/c question


i put a window unit in my girls house to help cool it during the heat last week. i have been in a discussion over fixing her central system here. she is not in favor of the unit setting in the window for some reason. so she has been looking at and talking to co-workers and they are talking about one of those units that you bolt to the wall and run the lines thru the wall and there is a unit just outside the wall that sets on the ground or the deck or a table and plugs into any outside outlet you have close by.

so what are those and are they any good? thanks for any ideas on these
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Old 08-29-2020, 07:31 PM   #2
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Re: a/c question


That’s a minisplit. Very popular and been around forever. But they don’t plug into an outlet. Even the 115V models should have a dedicated electrical circuit.
You can get cheap disposable ones off the internet or go with better built units like Mitsubishi or Samsung.
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Old 08-29-2020, 07:35 PM   #3
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Re: a/c question


They are called "mini splits". They do work well for space heating and cooling.

Was posting when @roughneck posted. But he is spot on.
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Old 08-29-2020, 07:38 PM   #4
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Re: a/c question


Why not replace the central?

mini-splits are all made in asia and loaded with proprietary electronics. there are good and bad applications for them.
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Old 08-29-2020, 07:39 PM   #5
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Re: a/c question


hey thanks that may be the way to go. and they may have to be on a seperate circuit but most people that have older homes are not going to bother with that you and i both know that. and if they are real popular is there any youtubes showing how to put these together? i figure the outside is plugged into the power but how does the inside unit connect to the outside unit? being i never heard of those i may have seen them and i remember mini split terms but never researched them. so do you cut a larger hole in the wall and push the inside unit thru it and then when the cover goes on it covers that hole? thanks
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Old 08-29-2020, 07:42 PM   #6
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Re: a/c question


You hang the indoor unit inside and then have to run refrigerant lines. These require refrigeration line work, to run the lineset between the indoor and outdoor unit. It’s not an appliance you pull out of the box and get it running 5 minutes later. You’ll need nitrogen, a vacuum pump, flair tools, gauges, a micron gauge, and other specific tools.
Code requires separate circuits. These aren’t window units. Most are 208/230V anyway.
You seem to assume lots of people want to do things wrong.
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Old 08-29-2020, 07:50 PM   #7
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Re: a/c question


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Originally Posted by user_12345a View Post
Why not replace the central?

mini-splits are all made in asia and loaded with proprietary electronics. there are good and bad applications for them.
well for one the general consensus here is i have to go thru a bunch of hoops to fix it. because it is 31 years old no local service shop will touch it without first putting in some kind of sealer. i have been down that road here with using a sealer or leak detector and the price of a new unit is just more than she can afford. so like i said i put in a window unit to get her thru the heat and to see if having one in the window would cool ther house as it has to not only cool the main floor but the basement because she has no door to the basement at this time.
the unit i put in was a 5400 btu unit and as we talked in another thread that was also testing the central unit to see if it was the central unit or the weather being too hot to even get the central unit to work. the window unit worked good enough that it cycled on and off. that is pretty good for a bedroom sized unit. anyway she was talking to co workers and they brought up one of those units that bolt to the wall and then the main unit sits outside and then she has all the windows to use as windows. so that is why at this point we have not yet decided to fix the central unit. thanks
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Old 08-29-2020, 07:57 PM   #8
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Re: a/c question


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You hang the indoor unit inside and then have to run refrigerant lines. These require refrigeration line work, to run the lineset between the indoor and outdoor unit. Itís not an appliance you pull out of the box and get it running 5 minutes later. Youíll need nitrogen, a vacuum pump, flair tools, gauges, a micron gauge, and other specific tools.
Code requires separate circuits. These arenít window units. Most are 208/230V anyway.
You seem to assume lots of people want to do things wrong.
ok thanks i guess those are not for her then i have not yet looked into them like i said i heard that word but did not know what they were, she brought it up today when i went over and tried to do a superheat on her system that i could not do because it just did not have enough r22 in it to measure any more. so that one has gone past repair. i will tell her to give in and let me put in a window unit big enough for the house. and i was not saying i would not hook it up electrically correct i'm am electrician i know the code. all i was saying is most would not bother. thanks
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Old 08-29-2020, 08:02 PM   #9
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Re: a/c question


If the central unit is mechanically sound and just needs a leak fixed/refrigerant charged just fix that.
Minis are not plug and play appliances. Even if you have a 115V model, you’ll be overloading circuits just plugging them into a common outlet.
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Old 08-29-2020, 08:03 PM   #10
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Re: a/c question


You can try a mini split DIY unit from Mr. Cool. easy to install, no need to hire an AC tech. You can search Youtube for the details.
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Old 08-29-2020, 08:13 PM   #11
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Re: a/c question


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You can try a mini split DIY unit from Mr. Cool. easy to install, no need to hire an AC tech. You can search Youtube for the details.
You’d still need refrigeration type tools like a flair block, nitrogen and a vacuum pump.
Avoid the precharged linesets. The connectors tend to leak refrigerant.
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Old 08-29-2020, 08:15 PM   #12
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Re: a/c question


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Originally Posted by roughneck View Post
If the central unit is mechanically sound and just needs a leak fixed/refrigerant charged just fix that.
Minis are not plug and play appliances. Even if you have a 115V model, youíll be overloading circuits just plugging them into a common outlet.
thanks. i have a friend from work when i was in maint at my shop coming over next week. we are both retired now and have time to mass with the central system. he has been doing this for 40 years and he said he will check it out and see if it is worth fixing. we both worked on the shop a/c units. i did the electrical repairs he did the rest.

this system may be ready now to retire as well. again thanks if i get any more replies in the other thread i will post this there so you know we are both talking about the same thing. this thread was about those mini split you called them. and now i know to tell my girl to forget them as i do not want to mess with it or bother my friend to install one. becasue she has central she might as well just put a new one in because the house is all set for that now, electrical and ducting etc. so price is going to be about a wash. and we will just set one in place of this old unit this fall or next year. thanks
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Old 08-29-2020, 08:40 PM   #13
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Re: a/c question


Shut it down until your buddy gets there. Not gonna do it any good to run it.
Minis are mainly spot coolers anyway, if you do a standard wall mount unit. You’d have to have several heads to do the whole house.
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Old 08-29-2020, 08:58 PM   #14
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Re: a/c question


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Shut it down until your buddy gets there. Not gonna do it any good to run it.
Minis are mainly spot coolers anyway, if you do a standard wall mount unit. Youíd have to have several heads to do the whole house.

roughneck the central is not running like i said in the other post we started it the other day and it ran for 3 days and did not do much if any good. i tested the pressure then and then 3 days later and shut it down. installed the window unit and today did the pressure test again and super heat test but it did not have enough r22 in it to do the super hear. i have unit oof 112# ls and 70 deg at the service port on ls 35# ls temp 56 deg cond temp 64 deg wet bulb 76 deg hs tem 65 deg at pump hs 158 deg at hs serviceport 83 deg and it held pressure at 39#

it was to low for the chart in the unit. and it is off. when my friend stops over we will go over and he can pull a vacuum and see if it holds. i'm betting it will not hold and he will do whatever to find the leak i guess. all i will do is help with any electrical work but i doubt i will have anything to do until we decide if it can be fixed or pull it out and replace it. he said he can get me a deal on a unit if needed.

so until he does his thing i wait. i was just hoping all it may need is a charge i can do that but with your help it looks like it needs more than a recharge. i would have called my friend but when i retired first he stayed working and i lost track of him last week i emailed the shop maint boss and he told me he retired and then the boss emailed me with his contact info, so today i emailed him and he got back to me a bit ago. now were are hooked up for this, so when he gets over here we will go figure it out. so yes it is off and soon i will have a better idea what is going on and let you guys know what was going on then. thanks and also no mini split. yes he can do it but like i just said the house is all set for central so might as well just put it back. thanks again
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Old 08-29-2020, 09:02 PM   #15
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Re: a/c question


No need to pull a vacuum. You’d then have to reclaim the remaining refrigerant left in the system. It’s illegal to vent refrigerant into the air.
Have your friend check for leaks with the system still charged. If he’s an HVAC tech he should have a leak detector.
Not to mention if you pull a vacuum on a system that’s leaking it’ll pull non condensables into the system.
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