What type of systems are you talking about? Sounds like "mini-spits"??? More than one mounted blower/evap. units connected to one condenser is pretty commonly done with these units. Need more information.:.02:

 

No not mini splits. It is Luxaire Lx equipment - traditional central AC. That is why I am asking.

 

Is this contractor REALLY experienced? This is not that common and would require numerous additional controls to work and be long lasting I'm afraid. How many experienced contractors came up with or agreed to this idea? My guess? Not any or many.

 

He is the only 1 of 3 that came up with the idea, but I do have to say is one that is well-known, established and has done a number of the homes on my block.

What additional controls do you mean? What are the concerns about long lasting?

 

How many of this type of split/split has he installed and does any of your neighbors have it in their homes? At the least you'll need freeze protection systems, tie-in relays, TXV valves sized properly, and if a HP system high pressure limit built into the single HP. The potential problem comes about when one blower/coil unit does not operate and the single operating blower/coil overloads, or freezes up from the over-sized condenser. These two blower/coil units must operate as one unit ALWAYS and if they don't it could rapidly damage the condensor (HP).:.02:


As to potential warranty issues from manufacturer (this would not be an AHRI matchup!!), then I would not even want to go there. I know of none of the manufacturer's who would cover these units installed in this manner, and then of course the installing contractor would then be responsible for warranty repairs. I'm not sure you would be happy with "no warranty" coverage. If you experienced numerous failures, the manufacturer would demand the indoor/outdoor model/serial numbers and then the gig would be up with the customer holding the bag (so to speak).

 

I don't believe he's done this type of solution on my block but I've got a unique problem. He said he does it 3 or 4 times a year out of several hundred jobs per.

 

If he has experience and can make it work, it's up to you to decide. But make sure you get warranty coverage in writing (if manufacturer fails to cover). Lots of companies now trying to deny coverage for non-AHRI installs so keep this in mind! I'd hate to see you stuck with repairs if lose warranty from Luxaire. :.02:

 

I wouldn't do it. Lux wouldn't approve and if/when there are issues, no support or warranty. As wahoo said, both units would run together which would cause comfort issues. Best bet is 2 outdoor units SIZED properly.

 

If it were me I would send Luxaire a copy of his proposal for them to look over and get a Yay or Nay from them directly. Just my 2 cents.

 

FWIW, I called Luxaire who referred me to a local person, who wasn't all that shocked by what I described and didn't think there would be a warranty issue.

 

One more thing . . . if this arrangement was unusual, is it possible to do a mini-split system where say the third floor had a ductless in wall unit and there were more conventional ducted areas on either side of the knee wall?

 

Try and get this "warranty issue" in writing from either the dealer who quoted the system or Luxaire themselves (at least their territory rep.). A few years from now any phone conversations will be honored for what they are....forgotten phone conversations. Assuming they'll honor the full warranty could be very expensive for you the final user. EVERYONE sounds optomistic while "selling" is going on.utergreet:

 

The quoted written estimate does say 10 year warranty.

 

I have a couple 10 ton heat pumps installed like this. They work fine.

Just a few precautions, and there won't be any problems with the method.

 

Also most mini splits are in the mid 20's for SEER range as compared to the average central unit at 13 - 15 SEER.

 

Mounting 2 coils on one AC unit 'can' be done from a tech perspective... couple of things:
I have installed a 'T' to feed two coils or two AH's which were side by side... but NEVER different locations or different loads (as in different floors). When one does the 'T'... the piping must be EXACTLY the same after the 'T' to assure similar flow to each coil.

Also: As noted by many folks: Warranty issues. I would have a signed paper on LX-air stationary saying this CAN Be done, in detail. Hate to see someone get 'caught in the middle' of a mess.

Personally... I would go the mini-split route. Even multiple single head systems would be a working arrangement as opposed to something questionable.