Keep us posted.
Regards Teddy Bear

 

Run your blower fan only put a accurate thermometer in a return(s) grille and one in your supply, you can move thermometer to different supply and returns. Check temperature difference, if your return duct is not leaking your temperature difference should be the same or very close. Do this when it’s a hot day.

 

Outside Temp 90
Indoor Humidity 37%

Return 75.7
Supply 65.2

Nest shows current indoor temp of 78. I set it to 75 and it's been going for nearly 2 hours and Nest hasn't moved from 78 indoor temp.

Thoughts?

 

If enough hot attic air is getting sucked into the unit or return ducting then yes it could be. You could try measuring the air temp right before the airhandler to see how it compares to your supply temps. Did the installer make any changes to the ductwork? Did the house originally have ac or just heat?

When the installer comes out ask for him to record the static pressure of the return and supply while the ac is running. Also wetbulb/dry bulb of return/supply. Have you ever had a duct leakage test done? Ask him to record all his measurements for your records and let us know

 

Outside Temp 90
Indoor Humidity 37%

Return 75.7
Supply 65.2

Nest shows current indoor temp of 78. I set it to 75 and it's been going for nearly 2 hours and Nest hasn't moved from 78 indoor temp.

The house had A/C and heat before. No changes were made to ductwork that I am aware of.

When we first bought the house, we opened up some walls, and found that 2 of the ducts were disconnected and essentially cooling the attic. Those leaks were addressed, but still didn't make a huge difference in overall comfort of home.

 

Outside Temp 90
Indoor Humidity 37%

Return 75.7
Supply 65.2

Nest shows current indoor temp of 78. I set it to 75 and it's been going for nearly 2 hours and Nest hasn't moved from 78 indoor temp.

The house had A/C and heat before. No changes were made to ductwork that I am aware of.

When we first bought the house, we opened up some walls, and found that 2 of the ducts were disconnected and essentially cooling the attic. Those leaks were addressed, but still didn't make a huge difference in overall comfort of home.

 

Start by throwing that POS NEST out!

 

But they look cool...lol.

Nest is such garbage, just spyware is all it is intended for.

 

Any chance you can measure the return air temp right at the air handler? How about a pic of the air handler install?I’d still recommend a duct leakage test done by an independent 3rd party

 

The 75.7 was the temperature I was getting underneath the air handler. The temperature right around the air handler in the closet about is 92.3. (Granted this is at 8PM now, and the outside temperature is now 81.) This is due in large part to the air pouring out the attic in to the closet where air handler is. This closet is located in main hallway of house with a louvered door that doesn't appear to be sealed tight.

Here's one more pic of air handler install further out:

 

If the air is pouring out of the attic there's a good chance a supply duct(s) are leaking.

Is that the only return?
What size is that?

 

That hole in the ceiling needs to be patched, it is drawing attic air into the house but I doubt that’s your only issue with that low of outdoor humidity. Honestly if that’s the work the installer did I wouldn’t let him back in your house. I agree with Pecmsg about the supply ducting, your paying to cool your attic. Need system running pressures, liquid and suction line temps, and outdoor/indoor dry and wet bulbs. Ask the installer to write these down for you along with supply and return static pressures. These are some of the measurements I would take coming up to your unit for the first time

 

I did reach out to the original contractor who installed the system, and explained my findings and he is coming on Friday to take a look. He said if he finds the installation was done incorrectly he "will make it right"

Did the Contractor show up as schedule on Friday? If so what was found?

 

It appears that the return opening in the platform is blocked by a piece of plywood when the door is closed. It is likely that most return air is coming through the gap in the ceiling and the open vent pipe. The presence of all the loose insulation on the floor is evidence of that.

 

Hi everyone. I apologize for delay--trying to push through frustration.

The original contractor did show up, but honestly he just offered excuses trying to justify why it wasn't operating correctly. He first started by saying he done the install right.

I then pointed out how they did not seal around the air handler when they placed it on the platform in closet, they did not close up attic space, they did not close up the holes they drilled in the platform to wire up the condensate removal pump, and they did not seal the louver door so that it was not pulling air from the hallway.

He backed off some when I pointed those things out. He offered to seal up around the air handler, but said he couldn't do anything with the ceiling. He then tried to tell me I did not have any ridge cap vents to let the heat out of the attic. (Which I kindly showed him I do) He also said it was not working correctly because of the single pane windows. He said air handler was sending out 54 degree cold air, and should be working fine. Said he would have secretary to call me when they could come back and seal around bottom of air handler, but I haven't received a call.

I just got the impression he wasn't to motivated to help me. So I'm done with him.

I went yesterday and sealed up the bottom of the air handler, platform, and door myself to try and basically stop the attic air from being sucked into the air handler. The attic air is still surrounding the air handler due to ceiling still open, but it shouldn't be able to get under the platform the air handler sits on due to all the sealing I did. This in itself made a huge difference in the amount of air coming through the returns. I know one person mentioned the plywood covering up the return. That is an old return that was abandoned. They placed a new return to the left that draws from the living, and there is another return in the ceiling of the main hallway of house. You can actually hear it drawing air through the returns now.

I even noticed an increase of air coming through the supplies. Yesterday we had outdoor temperatures of 103, and it was able to maintain temperature of 77-78. It cycled on and off a few times. It ran 15 hours total, but I'm not sure if it's in large part due to temp outside, if my attempt to seal it didn't help as much as I thought, or if I still need to have ceiling sealed so attic air isn't pouring in.

I have a spray foam contractor coming to give quote on spray foaming the ceiling to stop the attic air from pouring in. I have another a/c contractor coming Tuesday. I'm honestly looking at adding a 12,000 btu mini split to the living room to help supplement the main a/c unit since this seems to be the main place we can't get cooled down. All the bedrooms and bathrooms cool down fine, and you can feel they are much cooler than the living room where the thermostat is located.


That's where I'm at at the moment. Any thoughts on adding mini split? Spray foaming ceiling to seal it up? I also wondered should I look at adding a solar attic fan to help remove the heat from attic?

After around 10pm at night through around 1-2 pm the next day it is able to cool the entire house fine. But when the heat really kicks up around 2-3 pm that's when loses ability to cool below 77-78. Not sure if attic is holding lot of heat in? It's a pretty low attic.

 

Finish the insulation and sealing upgrades first before you start thinking about adding units.

103F outside is damn hot and you got to 77F.

Sent from my SM-G965W using Tapatalk

 

Before sealing up around the unit, it would be in your best interest to find a quality hvac contractor that can take proper static pressure measurements to ensure your ductwork is sized properly for your large 5ton unit.

A 5ton unit needs a large amount of ductwork. If you don’t have sufficient amount of ductwork both supply and return then your system capacity is reduced and also life of parts and components are degraded.

Whenever a larger air conditioner is installed, ductwork must be enlarged to properly move the increase of airflow needed with the larger unit. What size was your original unit?

A company that is proficient in taking static pressure measurements will be able to verify if your current duct system is large enough for your current system. It is quite common even when replacing same size equipment that was there, ductwork was never sized properly even for the size unit that was installed.

There are three points of needed static readings on your system:
1.) Before filter= ? I.w.c.
2.) after filter before evaporator= ? I.w.c.
3.) after the air handler before branch ducts= ? I.w.c.
Also need to know the speed tap the air handler is on= ?
And need the model number of the air handler?= ?

First make sure they seal the old return if not used below the furnace as it will affect the readings taken when the door is open.

With the above readings someone on this forum will be able to let you know how much airflow your unit is moving and if your ductwork needs work on the supply side or return side or both.

If it is determined that your ductwork is undersized, it is possible that renovating your ductwork will solve all your comfort issues.

Then once the ductwork is verified to be proper size or renovations have been done to the duct work to be the proper size. Then the ceiling can be closed up and sealed/insulated.

Good luck
J