Hi, I purchased and had installed from a trane comfort specialist(authorized dealer) a trane xl16c packaged unit.
4 ton r410a 16 seer.
It replaced an old 3.5 ton day and night packaged unit, probably at least 20-25 years old.
The reason I replaced the old unit, was the electricity costs were through the roof!
Anyways, the trane is installed and I am disappointed that I cannot get my temperature down below 80 degrees. I recall the old unit being able to go down and then "shut off" until the temperature needed to be cooled again.
I can only get this unit down to about 76 degrees at night (say 10:30 pm and after a long time running.
Even around 05:30 - 06:30 pm when its cooling down considerably, I cant get the thermostat to show below 80 degrees.
Basically, this unit runs constantly, dont the units have to "cycle a couple times an hour?"
My questions are this
1) I have a 16 by 25 return air filter and its a 16 inch round ducting to the return.
I have been reading that its mininum 18 inch round ducting for a 4 ton, is it possible to add another return box but keep the existing 16 inch round ducting? (its already installed in the attic and I have hardly any space in the attic)
If so, would the additional return box give it more air intake? Or would it be constrained by the 16 inch duct diameter regardless?
Would having too little return airflow give such a sympton as I'm describing?
2) According to the contractor, this 4 ton unit would work "good" for my house, he wanted to sell me a 5-ton split system, but he wouldnt install a 5 ton without upgrading my entire duct system at considerably more expense.
Since, he said the 4 ton unit would work "good", I decided on going with the high efficiency xl16c package, rather than the migration to a split system.
3) The digital thermometer they gave me is the TRANE tcont802 digital unit.
From reading the installer documentation, there is supposed to be a jumper "The installer must jumper at the LVTB "R" to "O" which I take to mean that on the control unit itself on the packaged unit, there should be a jumper setup on "R" to "O", what are the ramifications of not having that? It has to do with two stage cooling on the scroll compressor, and I dont know if they set that jumper, I rather doubt it, because its only documented at the thermostat documentation and not the package unit documentation.
Please, can anybody help here?
I also want to know If its realistic to expect a central air conditioner to be able to cool to about 78 degrees (or even less).
If so, how long should it normally take to cool a house down from say 85 degrees (at starting up of the unit) to 78 degrees?
I have been running the thing all day, and it never goes below 80 degrees, I am worried now, because I thought I was buying the trane quality and also went the right way in going with a trane dealer comfort specialist?
They tested the ducts and although my ducts are the old metal kind, they said the ducts were up to specs in terms of leakage (this test was administered by the company)