Adding Central AC to Hydro-Air System

[nriver1]

Hi-first...I am a newbie, so if some of my questions/terminology don't sound correct, please take my apologies in advance.

I received a quotation to add central AC (Carrier) to my hydro-air system. I have 2 zones, 2 air handlers and a weil maclean boiler.

The house is quite old (1796), but has had updated electrical (200 amps), new boiler last september, hydro-air handlers are less than 10 years old. Footage is about 1,850 sq. ft. Area is north shore boston, ma. Chiller lines already run up to the second air handler in the attic. it would seem like a really, really easy install to me...

My quote seemed high. Do I really need 2 compressors for a 2 zone hydro-air system to work? I don't want to reveal quote price because I would like to get some blind ranges on the price...

any thoughts? or flames?

[nriver1]

I just realied you pros on the forum can't talk price. Sorry...

How about the need for 2 compressors with the system I described?

Please ignore my questions about price...

Thanks.

[BaldLoonie]

You could do the upstairs first and since cool air falls, it would help considerably on the 1st floor.

[nriver1]

I could consider that...

I have read much about compressors with multiple speed settings/zones. I just wondered if there was a reason he didn't offer that option because of the 2 air handler hydro -air setup.

I guess I am just trying to educate myself. It's easier here than in front of him...

[Edited by nriver1 on 06-10-2005 at 03:28 PM]

[johnsp]

It's still one compressor to one coil. You have 2 seperate AH so you need 2 seperate coils. This is still the best kind of zoning you can do. Make sure he calcs the AC load properly. I would be suspicious if the the units were the same tonnage. Avg size home in Boston shouldn't need more then around 3 tons total. If they recommend more check with another contractor.

[dash]

Be sure the existing setup,blower and ducts can handle the addition of a wet coil (resistance)for cooling.


If you can post the air handler model ,someone may be able to post the fan data ,for it.