Can you post a pic of the new inside unit? Let us see what the install looks like.
I do not know what you mean "correct design temperature"
Originally Posted by second opinion
today was 102 and Saturday it will be 105
The installing company said that 95 used to be the design temperature , but after last summer with 60 days straight over 100 degrees then they now design for 105
as far as Delta T being low because fan speeds are too high...I have a variable speed blower that is low on 2 tons and high on 4
the $ between a 3 T system and a 4 T system is not much and 1.5 tons low would not have been adequate and system would have run constantly on 3 T , costing me more in energy usage
I will get you some pictures of outside unit and inside unit install
there was no central air in house before install on a 1950's house.
there was a centrally located coat closet which I personally converted into an equipment closet
It was a tight fit and a big effort to get 110 service , condensate drain and 3/4" gas service to unit
every inch counted installing a 24 x 28 in wide furnace into a 29 x 30 inch closet
used 1/4 cement board on walls to save space - plenty of return air from low returns on all sides and high returns on 3 sides
If its maintaining 78 when its 12 outside in first stage, then a 3 ton would have been plenty big.
A 3 ton would have cost less to use, then your 4 ton does.
10 deg delta is too low on 1st stage. I wonder if your fan is set up right? WHen you set the stat to fan on, then put on 1st stage cooling, is there a difference in the fan speed? It should remain at 50% fan in 1st stage.
And yet your 4 ton unit runs 95% of the time on 2 tons, but the 3 ton would run constantly on 3 tons!
Originally Posted by Night_Owl
Sorry your new unit is OVERSIZED!
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the dips that installed the system left all of the dip switches on default settings
so, since they never came out, or even called me back all week, I just put on my big boy pants and removed the bottom cover of furnace and set the dip switches correctly
was set to 5 ton default thus moving more air than what it should of for my tonnage
lower delta T's and quieter fan as well
was 106 on Saturday
unit ran all day on 2 T , except would kick up to 4 T about 3 times an hour for about 3 min each time
Id be a Happy Camper....
.....except there is still some air leaking from where coil meets furnace and the unused condensate drain fitting on coil