System struggling during daylight

[big chill]

My house is just over 2.5 years old and the AC has worked beautifully for 2.25 years. In May I noticed that the system seemed to struggle to get the temp down below 78 - 79 and runs constantly until about sundown. I called out the original installers, who determined that the evaporator coil was leaking and it would have to be replaced. I'll leave out the unnecessary details regarding the nearly two weeks of multiple problems in getting the coil installed, (cracking drain pan, replacing expansion valve, shorting out the thermostat, etc..) After all this, the system seems to be doing the same thing it originally was before I called them, running constantly until around 8:30 - 9:00 PM. I have the system set for 77 throughout the day and drop down to 75 after 3:30.

Heat Pump with Puron R410A
Bryant Model: 633AJX048000AAAA ( I believe 4 ton, 12 SEER )

The house is 2150 sqft with 10 - 12 ft ceilings throughout.

In Florida.

I would think with a 4 ton unit running properly, there should be no reason it can't get the house down to 72 - 73 if we wanted.

Does anyone have any ideas?

[dash]

Could you get it to 72° ,on a hot day in the past??


Most new construction homes are designed for 78° or 75°,in Florida.They can usually do a little beter then design ,but if designed for 78°,it's not likely to get to 72°,on a 90° plus day.

A lot of new homes are built with single pane glass and minimal insulation,so 4 ton could be needed to get to 77°.Depends on the construction.

There could unfortunately be something else wrong,have they come back to check it out?

[jacob perkins]

Originally posted by big chill
Does anyone have any ideas?

What is the level of humidity in your house?(relative humidity%,or wetbulb*)

An old old timer once told me ,"that the evaporators first job was to remove moisture from the air,and then to cool the air."
Maybe that is part of the problem.Too much of your 4 tons is being used for lowering reative humidity...could be infilration caused be kids coming in and out alot,leaks in ductwork,long setbacks of thermostat,ect..

Or maybe that oldtimer was just full of bull-ony.

Dash,what do you think?

[big chill]

Yes, but I haven't really had to have it that cool very often and I'm not sure exactly how hot it was outside when it did get that cool.

It just seems like it's not working as well since they worked on it. They have been back 3 or 4 times over the two week period to fix one thing or another. I'm just not very comfortable that they did everything correctly. There were five different technicians at my house during that period and I was comfortable with maybe two of them. Needless to say I wasn't seeing eye to eye with their dispatchers / service managers after two weeks of hell. I wan't to make sure it isn't working properly before I jump the gun and have them come back out.

[big chill]

Jacob,humidity is around 52 - 53.

No, kids, and very little in and out throughout the day. The best I can tell no leaky ducts. Settings on thermostat haven't changed....

[jacob perkins]

Originally posted by big chill
Jacob,humidity is around 52 - 53.


Well then,that means alot in Florida.50% is good in my book.(Maybe too good.)The unit is at least doing that much.

Only thing I can think to say has been stated:It might not be designed to get down to 72 degrees.

[BaldLoonie]

But if he says it worked beautifully for 2.25 years, it's gotta be sized right. Something has changed. After the coil change, did they get it evacuated and charged right? If it isn't cooling like it did, they ought to be able to find out why.

[jacob perkins]

Originally posted by BaldLoonie
find out why.

Okay.Maybe the electric strips are activated...

B'chill,has your energy bill been consistant with previous years,or have you had a noticable increase in kilowatt use?

[big chill]

They drew everything out, made the change and then recharged the system. They seemed to have a slight bit of trouble with the sub-cooling while they were checking it. I don't think it ever got to where they exactly wanted it. Is it charged right??? The two techs that were there seemed to think so.

[jacob perkins]

Did they use new refrigerant after repairing the coil leak?
Did you notice the color of the drum the refrigerant came out of when recharging?

[tinknocker service tech]

did they install a new liquid line filter dryer as required every time you havew to open a r-410a system.
this dryer will hold moistur and can cause a lot of problems while chargeing if not replaced. any time a system charge is removed and the lines are opened to air and moisture the filter dreyer must be replaced.

[Irishmist]

Hate to repeat myself but I don't see where anyone has asked the obvious question. Was a load calculation ever performed on this house? THAT is the ONLY definitive manner to determine if the capacity is correct. Also the air distribution system should be checked for proper sizing and airflow. If these criteria have been satisfied properly, and the problem persists, then start looking at possible mechanical causes. Depending on the design conditions, i.e. outdoor temp., temperature difference, etc. used in the course of the calculations, you will be able to determine if the size is correct. If in fact, the system is correctly sized, then I would start looking for a mechanical issue. If you don't get satisfaction from the contractor, ask for a factory representative (not his service manager or sales manager) to inspect the system. Most major manufacturers are more than willing to get involved, and Bryant is certainly a major player. They will probably want the contractor present, but that should not be a problem. Good luck. p.s. I can't emphasize enough, the importance of the load calculation being done.

[docholiday]

Setting the thermostat for 77 during the day and then trying to lower it to 75 while still in the hottest part of the day will take all you got and then some. These units are designed to maintain temperature even when it is in the 90's but asking it to pull down a house may be just over the edge. Try leaving it on 75 all day.

If your not confident its repaired then call the service manager back and ask that he come with a technician to ecxamine the system. Surely he is aware of the problems they have had over the past two weeks.

Also, depending on where you live you may have suffered some damp insulation or even some that was blown around in last years h'canes which may have changed the load on your home. I would at least look up there to see if thats possible.

BTW, you got another one heading your way now.

[big chill]

I'll try to answer all the questions in order:

Jacob, energy bill seems to be fairly consistent, maybe a touch higher. As far as I know they used new refrigerant. It was in a pink canister and they took a wrapper of the top.

Tinknocker, on the original repair they did change the drier, but they opened it up once to change the expansion valve and then again when changing the drain pan and they didn't. Would that have anything to do with a strange noise I'm now hearing? I'm hearing a slight crackling or bubbling sound in the air handler. It's not loud, but noticeable. I asked the technician what it was while he was there and he said it was just the freon condensing or expanding.

John, the system has worked for almost 2.5 years with nearly the identical settings, activity, temps, etc..

Doc, I tried to do what you suggested this past weekend. I had the settings at 76 for the entire 3 days. I noticed Sunday and Monday it hovered around 77 -78 until sun down.

[David-M]

Did these techs turn the pink bottle upside-down while re-charging? This is a must, as the R410a is a mixture and can't be charged as a gas. If not, more recovering and vacuum, then replace Puron AGAIN.