Had A New AC Installed, And I Don't Think Its Working Well Enough. - HVAC - DIY Chatroom Home Improvement Forum
Advertisement


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Like Tree5Likes
Reply
 
Thread Tools Search this Thread
Display Modes
Old 08-14-2020, 07:09 PM   #1
Member
 
Join Date: Dec 2019
Posts: 111
Rewards Points: 216
Default

Had a new AC installed, and I don't think its working well enough.


I just had a new Carrier 16 seer 3 ton condenser and a 2 stage Air handler installed in my 1600sq ft house in South Texas. Its been installed for a week or so, and I don't think its working as well as my 20 year old system before it went bad. I think I paid too much, and now when its 104 degrees out at 5 pm and 77 inside, I turned it down to 67. Two hours later at 7pm and 102 out it has cooled to 75. My old one would cool a few degrees in an hour when it was 110 out. The tech tried to tell me that 20 degree thing, but that's BS. Is this ridiculous for it to be only cooling that little?

Humidity percent is surprisingly in the low 20's right now

I'm about ready to hire someone who can use thermal cameras and such and see if I have some sort of leak that showed up suddenly and not slowly. Is there a way for me to test the "efficiency of how its working"?

Last edited by wthdideyedo; 08-14-2020 at 07:16 PM.
wthdideyedo is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 08-14-2020, 07:57 PM   #2
Member
 
Join Date: Sep 2012
Posts: 13,543
Rewards Points: 376
Default

Re: Had a new AC installed, and I don't think its working well enough.


If you have a thermometer check the return air temperature at the plenum if possible and the supply air temperature at the closest register to the unit.



This is more of that 20 thing.




A -- insta read -- digital thermometer is quick and handy but i've used cumbersome thermometers too.




Edit: Edit:
Attached Images
   
user_12345a likes this.

Last edited by SeniorSitizen; 08-14-2020 at 08:00 PM.
SeniorSitizen is online now   Reply With Quote
The Following User Says Thank You to SeniorSitizen For This Useful Post:
wthdideyedo (08-14-2020)
Sponsored Links
Advertisement
 
Old 08-14-2020, 08:03 PM   #3
Member
 
user_12345a's Avatar
 
Join Date: Nov 2014
Location: Canada
Posts: 12,464
Rewards Points: 86
Default

Re: Had a new AC installed, and I don't think its working well enough.


At around 50% indoor humidity you should see a 17 to 22F temperature drop across the air handler. If you want to be more accurate, can measure something called return air wetbulb in addition to drybulb (normal temperature) and determine what the supply temperature should actually be using a chart.

It's possible your unit isn't properly charged and or they never wired up the second stage and it's running on low.

Was the old unit a 3 ton?

Normally a correctly sized unit won't be able to pull the temp down much at 110f outside, but if you kept the size the same, something's wrong. New units of the same tonnage tend to have the slightly lower capacity, but the difference shouldn't be dramatic.
__________________
I am not in the business of any trade I give advice on. I have non-professional hvac experience + good knowledge of theory. Attempt repairs at your own risk. Never jump out safeties - especially pressure switches - on a furnace for testing with fuel supply on; use a meter. Do not troubleshoot with live line voltage present unless there's no alternative.
user_12345a is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 08-14-2020, 08:28 PM   #4
Member
 
Join Date: May 2015
Location: Canada
Posts: 8,073
Rewards Points: 80
Default

Re: Had a new AC installed, and I don't think its working well enough.


A properly sized ac will lose ground, a few degrees on the warmest day expected. They are sized to big enough for 98% of the time. That means that they will usually be catching up at night. For these heat waves, you shouldn't turn off your ac, and inside leave it running day and night. If it keeps up then it's working as expected.

As user mentioned, there very well could be real problems. Measure the temp as mentioned above. Model numbers will help us be more specific.

Cheers!
Dave Sal likes this.
supers05 is offline   Reply With Quote
Old 08-14-2020, 09:01 PM   #5
Member
 
Join Date: Dec 2019
Posts: 111
Rewards Points: 216
Default

Re: Had a new AC installed, and I don't think its working well enough.


I don't, but I think its worth spending $10 if that will tell me something.
wthdideyedo is offline   Reply With Quote
Old 08-14-2020, 09:06 PM   #6
Member
 
Missouri Bound's Avatar
 
Join Date: Apr 2011
Location: Almost Arkansas
Posts: 3,876
Rewards Points: 4,226
Default

Re: Had a new AC installed, and I don't think its working well enough.


Quote:
Originally Posted by wthdideyedo View Post
I'm about ready to hire someone who can use thermal cameras and such and see if I have some sort of leak that showed up suddenly and not slowly. Is there a way for me to test the "efficiency of how its working"?
Why? It's pretty clear that the problem is with the new unit.
Did you replace the old unit with one of the same capacity? Or did the salesman tell you that you needed a differently sized unit?
And why did you replace a working unit in the middle of summer?
__________________
Do you want it your way or the right way?
Missouri Bound is offline   Reply With Quote
Old 08-14-2020, 09:14 PM   #7
Member
 
Missouri Bound's Avatar
 
Join Date: Apr 2011
Location: Almost Arkansas
Posts: 3,876
Rewards Points: 4,226
Default

Re: Had a new AC installed, and I don't think its working well enough.


[QUOTE=wthdideyedo;6262277] The tech tried to tell me that 20 degree thing, but that's BS. Is this ridiculous for it to be only cooling that little?

/QUOTE]

The "20 deg. thing" is relevant to indoor temperature only.
Cooling relys on the difference between supply and return air.
Yes, outside air does affect the operation of the equipment.
But for the most part if you are getting a 20 deg. difference between the supply and return then the equipment is most likely performing as well as it can.
Perhaps the issue is in blower speed, filtering or some other change made during the installation.
__________________
Do you want it your way or the right way?
Missouri Bound is offline   Reply With Quote
Old 08-14-2020, 09:29 PM   #8
Member
 
Join Date: Sep 2012
Posts: 13,543
Rewards Points: 376
Default

Re: Had a new AC installed, and I don't think its working well enough.


Quote:
Originally Posted by supers05 View Post
A properly sized ac will lose ground, a few degrees on the warmest day expected. They are sized to big enough for 98% of the time. !
******************************************
In TX this is the very best way to only be required to host 1 hot summer evening party with 8 or 10 guests. By the time the guests begin to arrive it's 80F in the house and within an hour its 83 or 84 degrees. But that's ok because half of the guests have already departed and things are looking up for the remaining drunks that could tolerate the heat.
SeniorSitizen is online now   Reply With Quote
Old 08-14-2020, 09:35 PM   #9
Member
 
user_12345a's Avatar
 
Join Date: Nov 2014
Location: Canada
Posts: 12,464
Rewards Points: 86
Default

Re: Had a new AC installed, and I don't think its working well enough.


Quote:
But for the most part if you are getting a 20 deg. difference between the supply and return then the equipment is most likely performing as well as it can.
It's just a preliminary test.

There can be problems despite having a normal drop. (like using first stage only or a combo of low airflow and refrigerant charge issue - the low airflow can cover things up)

I would look further despite having a normal temp drop.
__________________
I am not in the business of any trade I give advice on. I have non-professional hvac experience + good knowledge of theory. Attempt repairs at your own risk. Never jump out safeties - especially pressure switches - on a furnace for testing with fuel supply on; use a meter. Do not troubleshoot with live line voltage present unless there's no alternative.
user_12345a is offline   Reply With Quote
Old 08-14-2020, 09:38 PM   #10
Member
 
Join Date: Dec 2019
Posts: 111
Rewards Points: 216
Default

Re: Had a new AC installed, and I don't think its working well enough.


When he first installed it, he put the air handler on medium, then put it up to med/high after I said it was blowing weak. He didn't seem to be too familiar with it.
wthdideyedo is offline   Reply With Quote
Old 08-14-2020, 09:38 PM   #11
Member
 
Join Date: Sep 2012
Posts: 13,543
Rewards Points: 376
Default

Re: Had a new AC installed, and I don't think its working well enough.


Quote:
Originally Posted by wthdideyedo View Post
Is there a way for me to test the "efficiency of how its working"?
*************************************************
That Delta T test is the least expensive and best efficiency test you as a home owner will ever do. If you are unable to check the return temperature at the plenum at least use room temperature for a starting point.


If the D T is way off then we might begin looking for a dis-connected or partially dis- connected return duct in the attic if that's where return ducting is. A 6 or 8 inch return sucking 130 attic air will change efficiency in a heartbeat and you'll see it on the D T test.






Edit: Edit:

Last edited by SeniorSitizen; 08-14-2020 at 09:41 PM.
SeniorSitizen is online now   Reply With Quote
Old 08-14-2020, 09:42 PM   #12
Member
 
Missouri Bound's Avatar
 
Join Date: Apr 2011
Location: Almost Arkansas
Posts: 3,876
Rewards Points: 4,226
Default

Re: Had a new AC installed, and I don't think its working well enough.


Quote:
Originally Posted by wthdideyedo View Post
When he first installed it, he put the air handler on medium, then put it up to med/high after I said it was blowing weak. He didn't seem to be too familiar with it.
The real cost of having HVAC equipment is not the cost of the equipment.....it's living with the result of the company that installed it.
The best company can make even the cheapest equipment work well and do what it is supposed to do.
A poor company can give you a miserable experience for the life of even the best equipment.
Dave Sal likes this.
__________________
Do you want it your way or the right way?
Missouri Bound is offline   Reply With Quote
Old 08-14-2020, 09:44 PM   #13
Member
 
Join Date: Dec 2019
Posts: 111
Rewards Points: 216
Default

Re: Had a new AC installed, and I don't think its working well enough.


If it helps:
AC Carrier 24abc636a003
Air Handler Carrier fx4dnf037l00
wthdideyedo is offline   Reply With Quote
Old 08-14-2020, 09:44 PM   #14
Member
 
user_12345a's Avatar
 
Join Date: Nov 2014
Location: Canada
Posts: 12,464
Rewards Points: 86
Default

Re: Had a new AC installed, and I don't think its working well enough.


Single stage a/c with basic 3 ton ecm air handler.

The fan needs to be on high.

Can't find a install manual right now - installer needs to verify proper airflow, temp drop, refrigerant charge using correct method.

One other thing you can do is measure the suction line temperature - large insulated pipe going to the outdoor unit. It should be below 60F, ideally in the 50s at normal airflow and typical return air temp.
__________________
I am not in the business of any trade I give advice on. I have non-professional hvac experience + good knowledge of theory. Attempt repairs at your own risk. Never jump out safeties - especially pressure switches - on a furnace for testing with fuel supply on; use a meter. Do not troubleshoot with live line voltage present unless there's no alternative.

Last edited by user_12345a; 08-14-2020 at 09:54 PM.
user_12345a is offline   Reply With Quote
Old 08-14-2020, 10:01 PM   #15
Member
 
Join Date: Dec 2019
Posts: 111
Rewards Points: 216
Default

Re: Had a new AC installed, and I don't think its working well enough.


supposed to be single stage AC, with dual stage blower which allows for humidity control.

I saw when he changed the setting and said it was med to med/high, I know I need to just turn it off, turn off the disconnect and open the panel. I need to find a manual or something on it before I do that so I know which setting it needs to be on for it to be on high. I think the tech thought it should be on the lower setting so the dual blower could kick on higher. Could I guess he had that backwards, and I need it on high, and the dual stage would be lower?
wthdideyedo is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Top of Page | View New Posts