[vote4Pedro]

the house i'm in now has a 1.5 ton AC unit for a 1400sq feet 3 floor house. During purchasing, we pointed out that it may be undersized for the house and was not compensated for it due to sellers fancy engineering spec paper which we couldn't read in addition to being winter and hard to determine. come summer, it's HOT... i can't cool the house below 80 degrees. when it's 87 outside.

needless to say the AC component of the HVAC needs to be replaced. I was wondering if this is a simple compressor swap or is it more involved as in ripping the entire hvac system out??

i've already have some HVAC guys out and they've checked the pressure of the system and determined that maybe not sufficient air gets pushed through in addition to the small compressor.

i hope it's not too much money.. ~fingers crossed~

 

[gregzoll]

1) Not a DIY job. 2) Really need minimum 3 bids from reputable companies, not some bubba driving around looking for work. 3) Hard to tell unless you have a Manual J done and also depends on where you live, how well the house is sealed & insulated. One home that is a 1400sqft may work with a 1.5 ton, another home that is 1400sqft may not, it is really hard to tell, unless the calculations are done correctly to determine.

 

[Marty S.]

Something didn't get built right if the load calculation calls for a 1.5 ton and it can't cool below 80 degrees. Check that all the duct is sealed, all ceiling penetrations are sealed, doors and windows don't leak and that there's at least R49 in the attic.

If you're letting the house get hot before turning on the AC or using a set back then don't. Set the thermostat on 75-76 and leave it alone.

 

[vote4Pedro]

it's a almost 100 yr old brick house if insulation is concerned. i can feel the cold air coming out of every duct. however it feel like the pressure is not enough to cool the room.

 

[gregzoll]

Really need to do a Manual J. Just because it is a 100 year old Brick home, does not make it known how it heats and cools.

 

[vote4Pedro]

i'm going to climb to the attic to see if there's a leak and/or r49 in there? i can't find 1 room that is particularly cold.

will def get a HVAC person here to give me an estimate.

 

[vote4Pedro]

today was a good day to test the AC unit. the hi for the day was 94 and it's now 85.1 degrees outside. I've set the thermostat to 72 and after 4-5 hours of blowing, basement read 73, 1st floor read 83 while the top floor read 86 using a laser temp reader. I was not able to find one room particularly cold outside of the basement. do you think there's a leak in the pipe in the basement? i simply feels like that there isn't enough air being pushed through to cool the upper floors.

 

[gregzoll]

Could be a leak in a piping joint, could be that the house has air leaks and not properly insulated, especially in the Attic area, and along the Rim & Sill joists in the basement, along with outside entrances not possibly having weather stripping. I run a remote sensor in my attic & basement, so that I can continually monitor the temps in those areas. Today my attic was 105.1 at the peak of the day, outside was 89.7 at the highest. Basement around 67, upstairs 72, so yes there is a small bit of differently between basement & first, but overall within what I want it to be at.

 

[vote4Pedro]

dumb question, is there a fan that's inside the hvac system? could the fan be not spinning?

 

[gregzoll]

It could just be that the coils for the AC that sit above the fan are clogged, even though you do not see icing, it can be enough to cause low airflow. Same if your system was not properly calculated for the house, and just thrown together at minimum spec's. There are tools avail that measure air flow & temp. For temp, I use a thermometer that I use for in the kitchen that measures down around 0 degrees that I take around and place at the vent on top of my unit downstairs, and various vents around the house to make sure I am still well within specs before cooling season starts.

 

[vote4Pedro]

i believe that the system is not properly calculated was the issue. during the calculation, they prob didn't factor in basement to save some $$. not to mention that the previous owner's father ran a construction company and had some of their workers work on the house in the spare time resulting in some head scratching repairs in other parts of the house as well


regardless, i have called a hvac person that has been referred to me. he states that a min of 2.5 ton should of been used for a house of my size. however i will need to get all the part numbers (inside and out) to him so he can gauge if it's sized correctly.

 

[vote4Pedro]

outside unit is a trane xb 1000
http://www.acservicenow.com/products/split_outdoor/xb1000.html

inside is york diamond 80??
http://www.yorkupg.com/homeowners/furnace.asp
american standard inc
model: TXc024c24c4hpc0

any suggestions as what i'm looking at??

thanks

 

[vote4Pedro]

in the spirit of trying to create less threads. quick question for the HVAC pros.

the outside unit listed above sits below a set of deck stairs giving it very little room to "breath". the hot air pushed out is essentially in a enclosed area so could this be a factor as to why my ac unit can't cool the house?

 

[bob22]

10 SEER is very inefficient as is Diamond 80 given new models' stats; if you can afford it, upgrade to newer, improved efficiency units (a get same mfg so they are matched).

 

[gregzoll]

in the spirit of trying to create less threads. quick question for the HVAC pros.

the outside unit listed above sits below a set of deck stairs giving it very little room to "breath". the hot air pushed out is essentially in a enclosed area so could this be a factor as to why my ac unit can't cool the house?

Yes, it could. Take a picture of the outside unit showing enough to get an idea what you are seeing.

 

[Marty S.]

in the spirit of trying to create less threads. quick question for the HVAC pros.

the outside unit listed above sits below a set of deck stairs giving it very little room to "breath". the hot air pushed out is essentially in a enclosed area so could this be a factor as to why my ac unit can't cool the house?

Huge factor. Your 1.5 ton could be working as a 1 ton or less. There's supposed to be 4 foot minimum of free air space over the unit and 3 foot from sides. Side closest to the house can be 1' away though. Inside and out it's all about air flow.