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High Velocity HVAC in Washington, DC

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everett volk

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Discussion starter · #1 ·
Hi all,

This is my first time posting to the forums here, mostly I just lurk and read. However, my wife and I are interested in having a high-velocity air conditioning system installed in our 90 year old row-house. I'm not sure if this is the proper forum for this question, but has anybody out there had any good experiences with DC contractors having this done? I'm leaning towards a Unico system, but would consider Space Pak, if the contractor had good recommendations.

Thanks!
 
#2 ·
Your are correct in being careful.
These systems are noisy, and the installation is critical to correct operation.
Some common mistakes are, duct runs too long or too short.
Less than six runs per ton.
Suction pipe too small for the long length.
No sight glass at the evaporator.
and charging the unit by superheat, (use subcooling).
Poor dehumidification and frost on the evaporator coil is also an issue.
Unico publishes a good installation guide that I think you should be familiar with so you can keep an eye on your installer.
For my money, I prefer Mitsubishi Mr. Slim.
http://www.mrslim.com/Products/Category.asp?ProductCategoryID=24


[Edited by acoolguy on 06-01-2006 at 11:26 PM]
 
#3 ·
Get references and have them show proof that hi-velocity systems they have installed are running properly.

Ask each contractor what their procedures are and then check back here with the results. We'll help ya out.
 
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#4 ·
Noisy?

I used to work for company that installed Unico and I never even knew the system was running when inside the home or business unless I got too close to the diffussers and felt the air blowing on me. These systems have mufflers, if properly installed in the correct locations, that keep the decibels lower than the typical low velocity system. Mr Slim is hardly appropiate in some circumstances where the smaller duct/high velocity systems work well especially in older historical dwellings.

Richard
http://highperformancehvac.com
 
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Discussion starter · #5 ·
Ductless Minisplits?

Thanks for the replies y'all. One of you mentioned Mr. Slim, the minisplit from Mitsubishi. I've been looking at that and the Fujitsu minisplits as well. They also seem like they might be a good option for my house.

One of the difficulties I'm going to face (okay, my contractor, really), is that there really isn't any attic space. There's about a 2 foot space in the front of the house that decreases as you go back because the roof slopes to the back. I think it would be pretty difficult to get even a 2" duct to the back rooms without a lot of trouble.

My concern with the ductless minisplit is that they don't seem to be very good at dehumidification. Is this correct or, if I put in a minisplit, will I also get adequate dehumidification (assuming proper design for the load in the house)? This is DC, so humidity is HIGH!

Thanks,
Everett
 
#6 ·
Humidity

Space Pak has a six row evap coil, better for humidity control. Unico uses a four row.
Space pak uses 3 foot long mufflers on each run, I'm not sure what Unico uses
 
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