20 yr old split system replacement

[davef]

I have a 20 yr old trane 5 ton split system with two 2.5 ton condensors and one 5 ton air handler. Right now the evaporator that goes with the newer condenser is covered with ice. The tech who answered the call said that if I were to get a new system it would be two separate 2.5 ton units each with their own air handler and duct work. Do you think that a single 5 ton system would be better? And have you ever heard of the configuration I have now? On my current system the 2nd system lights off when there is a 5 degree difference between the thermostat setting and the indor temp, is that a very effective method of cooling a house? I live in NE Florida in a single story brick house with 3000sqft. I would appreciate any responses to my questions.

[Steve Wiggins]

Why not go back with a new 5 ton system with two compressors inside a single outdoor unit? Trane or American Standard brand.

[davef]

The technician metioned that the return duct was probably undersized. Is it more efficient to have two systems in a house or one larger one?

[beenthere]

dave, you have a 2 stage system.

Did you like the way it worked before it gave you trouble.

If so, get another 2 stage system.

The tech that was there, isn't familair with 2 stage systems.

Trane has a model with dual compressors in it.

Other manufactures have single compressors that are 2 stage.

[davef]

The way it was explained is that the two units outside that are about 6 feet appart are separate condensors I would assume each had its own compressor, and evaporators which are side by side in the air handler. The mechanism that causes the second unit to start sound kind of ridiculous a 5 degree temp disparity for the thermostat. This seems very erratic. It seems that most of the service and repair done to this system was under American Homeshield which would just mean a series of cheap fixes.

[beenthere]

Get a couple of estimates from contractors that install 2 stage equipment.

A newr unit should be more reliable, and eff.

Have you made any improvements to your house, such as insulation, air infiltration?

This may cut down on the size unit you need.

The newer 2 stage units with VS blowers are able to remove more humidity.



2 stage twin circuits residencial units are around here still, just not as many anymore.

[davef]

I have all but made up my mind to do the 2stage replacement. Would improving the insullation of the house prior to sizing and installing a new A/c be immediately cost effective in the savings in the size of the new system? Thanks for your answers so far.

[beenthere]

Yes, it could lower your unit size by a ton, maybe even more.

A 5 ton 2 stage unit will cost alot more then a 4 ton.(not allowed to say more about prices on this board)

That equals lower up front cost, plus lower operating cost forever.

You should always address the insulation and windows doors first.

[davef]

Thanks very much. I think I'm heading in the right direction now.