Questions about ductless A/C


Old 07-30-14, 12:55 PM
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Questions about ductless A/C

I have a few questions about ductless A/C. My house has hot water heat so there is no ductwork. The cost to install it for central A/C is too much money considering I only need the A/C for about 1-2 months a year. Ductless A/C seems the best way to go. My house is a rambler with a basement but I only plan to cool the main living area (living room, dining room, kitchen) So, here are my questions:

Can these units be easily installed by my husband and I - we are both pretty handy (we would hire an electrician to do the wiring)?

Can the inside unit be hung on a ceiling?

Are there brands you recommend? Ones to stay away from?

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Old 07-30-14, 02:27 PM
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Not an A/C pro, but I can tell you what I know.

Wall units are designed installed on a wall. They do make inside units designed to be installed in ceilings.

From what I have learned, you can install one yourself. However, manufactures will not warranty them so you are better off to have them installed by a pro. The only place I have seen to get mini split systems for DIY is online.
Old 07-30-14, 03:28 PM
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Mechanically fastening the indoor unit to the wall or ceiling as befits the particular unit IS definitely DIY friendly. Mounting the outside unit can be DIY friendly. Running conduit or cable for the electrical portion can be DIY friendly depending on your skill set.

The problems arise when it comes time to connect the refrigeration tubing and commission the units. The flared tubing connections are critical and they need to be made very tight, but not too tight. The manufacturer's recommend using a torque wrench and that tool alone will likely set you back $100. Most units will have enough refrigerant for either a fifteen foot or a twenty-five foot "lineset" and if your lineset is a different length than specified you will have to add or remove refrigerant. Changing the amount of refrigerant requires many more tools and the cost will quickly rise as will the difficulty in learning the use of these tools.

Even if you get a unit with the proper refrigerant charge for the lineset it is best to first do a pressure test to see if you have any leaks and then to vacuum the system to remove all air and moisture. The pressure test requires a cylinder of 99.5% pure nitrogen, a pressure regulator and a manifold gauge set. The vacuum requires a high vacuum pump and gauge in addition to the manifold gauge set. The instructions on the least expensive units will tell you that you can pressure test with just the refrigerant charge in the system but if you have leaks you will need to add refrigerant. Also, without using the vacuum pump you can leave air and/or moisture in the system that will cause all kinds of problems.

High end units are made by Mitsubishi and Sanyo. Chinese "knock-offs" will have prices starting at about $1200 to $1500 depending on capacity. The high end brand names will be double those prices or more.
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