A/C runs constantly

[GenesisGuy70]

Hi there,

This is lengthy but I need a proper diagnosis.

Problem: This A/C runs upwards of 12 hours a day even when it's only in the 80's outside and the thermostat is set to 73. It can be 75 outside and I'll have the Nest set to 72 and it will take hours to drop 3 degrees. It doesn't dehumidify at all. I bought a dehumidifier that removes about 8 gallons a day even with the air conditioner running all day. Humidity is about 68% when the a/c is on and the dehumidifier is off. This system was completely discharged and recharged to the superheat specs by a certified tech that works for my apartment complex.

Apartment specs: The building is two stories, I live on the second floor. This is a "pull-down" system and has one return in the middle of the apartment. it's 1100 square feet with 3 windows and a standard slider for patio entrance. The windows are new and well sealed.

More notes: The system seems to have a hard time getting enough air flow into the supply. The indoor part of the system is in a small closet with the hot water tank. The blower is trying to pull so much air it literally sucks the door closed when it's on. So I don't think the supply vent provides enough.

I have a 3rd Gen Nest installed. Usage lately is as follows (sorry so big). Weather during this period ranged from 60's to mid 90's.:

Equipment:
Condenser: http://www.goodmanmfg.com/docs/librariesprovider6/default-document-library/ss-gsc13.pdf?sfvrsn=0

A-Coil: http://www.goodmanmfg.com/docs/librariesprovider6/default-document-library/ss-gcoil.pdf?sfvrsn=0

Return:

Tech specs: The supply line from the condenser reads at about 56 degrees right before it enters the a-coil. The nearest vent is always at 12 degrees warmer. So it's losing 12 degrees of coolness in about 3 feet. The duct system is in the ceiling, which is the technical attic for the building. This is where I think it picks up a ton of heat. The return/supply split is never greater than about 12-14 degrees.

I think this system runs way too long and does a horrible job of dehumidifying. Am I wrong?

Thanks

 

[04SE]

72*? Yikes!

We keep ours on 77 and run 2 fans. We are more than comfortable.

 

[Triple_Se7en]

I agree, 72 is really cold.
I keep mine on 77 during the day and 80 overnight. When outdoor temps dip into the 70s during the day (like today) I shut the A/C off and open windows.

 

[GenesisGuy70]

Originally Posted By: 04SE
72*? Yikes!

We keep ours on 77 and run 2 fans. We are more than comfortable.


Well it depends. Usually 73 during the day, 75 at night. When it was 93 degrees the other day I turned it up to 80 because it had literally run from 8am to 3pm without shutting off ONE time.

Maybe I just expect to much. I just feel that an apartment only 1,100 sq ft should be able to be cooled to 73-75 without any problems. Especially with a freshly charged system and a brand new blower and a-coil. And ESPECIALLY when it's only in the 80's out. Now when it's in the 90's I can see it running quite a bit. But when it's 85, it should be able to cool a mere 12 degrees lower without running 12 hours straight without shutting off maybe once or twice..

 

[bbhero]

Well mine is 68. Way cooler than that

 

[Brybo86]

have you tried propping the down open and see if the extra air flow helps with cooling?

 

[Kuato]

Originally Posted By: Brybo86
have you tried propping the down open and see if the extra air flow helps with cooling?


That would definitely help - I'd be considering putting a grille in the door to allow airflow; I've seen some setups like this in tight places and it worked well.

Since the ducts run in the attic - where it's hot - I would insulate those thoroughly.

Make those 2 changes and you should see a world of difference.

 

[Nick1994]

That isn't too cold. I keep the A/C in my house set to 73, I have a programmable thermostat that keeps it at 76 from 6am-5pm. Then 73 from 5pm-6am, 73 degrees on the weekends.

So it just went from 76 to 73 and just shut off after running for 1-1/2 hours. And it's over 100 degrees outside, single story 1400 square foot house.

There's something wrong with your A/C, call in a pro. If they find the problem and fix it, your electric bill might go down enough to pay for the service call real quick.

Do you own the apartment or rent? If renting, complain to the landlord, you shouldn't have to pay an electric bill for a defective A/C unit.

 

[sleddriver]

Sounds like your return air is way undersized, the fan speed is wrong and your evaporator is dirty.

What's the air temp drop between return & supply?

 

[GenesisGuy70]

Originally Posted By: sleddriver
Sounds like your return air is way undersized, the fan speed is wrong and your evaporator is dirty.

What's the air temp drop between return & supply?


A-Coil is brand new, only been in use for 3 weeks. I cleaned the outside condenser fins with coil cleaner and water. Split is about 12-14 degrees. Lower on really hot days.

 

[GenesisGuy70]

Originally Posted By: Nick1994
That isn't too cold. I keep the A/C in my house set to 73, I have a programmable thermostat that keeps it at 76 from 6am-5pm. Then 73 from 5pm-6am, 73 degrees on the weekends.

So it just went from 76 to 73 and just shut off after running for 1-1/2 hours. And it's over 100 degrees outside, single story 1400 square foot house.

There's something wrong with your A/C, call in a pro. If they find the problem and fix it, your electric bill might go down enough to pay for the service call real quick.

Do you own the apartment or rent? If renting, complain to the landlord, you shouldn't have to pay an electric bill for a defective A/C unit.


I rent, I could probably call in an outside company in on the weekends. I don't think the managing people would approve. If there is something wrong with ducts I have no access to them unfortunately and I HIGHLY doubt the landlord would approve anything like that.

 

[GenesisGuy70]

Originally Posted By: Throt
Originally Posted By: Nick1994
That isn't too cold. I keep the A/C in my house set to 73, I have a programmable thermostat that keeps it at 76 from 6am-5pm. Then 73 from 5pm-6am, 73 degrees on the weekends.

So it just went from 76 to 73 and just shut off after running for 1-1/2 hours. And it's over 100 degrees outside, single story 1400 square foot house.

There's something wrong with your A/C, call in a pro. If they find the problem and fix it, your electric bill might go down enough to pay for the service call real quick.

Do you own the apartment or rent? If renting, complain to the landlord, you shouldn't have to pay an electric bill for a defective A/C unit.


I rent, I could probably call in an outside company in on the weekends. I don't think the managing people would approve. If there is something wrong with ducts I have no access to them unfortunately and I HIGHLY doubt the landlord would approve anything like that.


I think I'll buy, or rent if possible, one of those snake cameras or whatever they're called and look into the ducts that way and see if I can see apparent leaks or collapses or whatever might be up there.

 

[xshoex]

Originally Posted By: 04SE
72*? Yikes!

We keep ours on 77 and run 2 fans. We are more than comfortable.


My ac is 72 for prob 10 months of the year. I don't even touch it, the 2-3 months it is cold I put the heat at 69

 

[JayhawkRoy]

Contact your landlord and have the landlord arrange for a call back on the A coil. Tell the landlord current symptoms and the fact the house is not being cooled correctly. Landlord needs to handle this since it could involve a warranty issue or may be a newly developed issue.

Since you are not a pro, I wouldn't do any diagnosis at this time. Don't give your landlord any excuse to blame you and your actions for anything that has transpired.

 

[cptbarkey]

An AC running at 72 is insanity. We keep ours around 75 and it runs alot, but I get cheap electricity so I dont care.

 

[04SE]

Originally Posted By: Throt
Originally Posted By: 04SE
72*? Yikes!

We keep ours on 77 and run 2 fans. We are more than comfortable.


Well it depends. Usually 73 during the day, 75 at night. When it was 93 degrees the other day I turned it up to 80 because it had literally run from 8am to 3pm without shutting off ONE time.

Maybe I just expect to much. I just feel that an apartment only 1,100 sq ft should be able to be cooled to 73-75 without any problems. Especially with a freshly charged system and a brand new blower and a-coil. And ESPECIALLY when it's only in the 80's out. Now when it's in the 90's I can see it running quite a bit. But when it's 85, it should be able to cool a mere 12 degrees lower without running 12 hours straight without shutting off maybe once or twice..


I had similar problems, to be honest. I did the following, with amazing results, all of which you unfortunately can't do as a renter. Keep in mind that your dehumidifier is surely dumping warm air into your apartment that your A/C is now trying to remove.

1. installed 2 gable vents - HUGE difference
2. sealed all supply/return line joints with mastic (supply is in crawl and return is in attic)
3. sealed all return 'boots' to ceiling
4. regularly clean condenser every 2-3 weeks during peak usage and 2-3 times a year I hit it with simple green
5. adjusted damper valves in supply lines to balance/regulate supply across whole house

What type of filter is being used? I have experimented with filters (20x20x1) on my Rheem and the Ace & Menards cheapie pleated filters work best by balancing cleaning and flow. The expensive pleated filters definitely cut my air flow way down and the cheap fiberglass filters seem to have too much flow and the air doesn't exchange heat it seems with them.

 

[GenesisGuy70]

I printed out the wiring diagram for this furnace, under cooling stage the blower was wired to run on High, under heat, run on medium. I reversed the two. Slowing the air should allow the air more time to have heat removed and increase dehumidification. If Medium doesn't work I have wires for Med Low and Low available also that are on a park terminal. Hopefully this will help. If not, I'll continue my steady march to figuring out what the heck is going on here.

 

[GenesisGuy70]

Originally Posted By: 04SE
Originally Posted By: Throt
Originally Posted By: 04SE
72*? Yikes!

We keep ours on 77 and run 2 fans. We are more than comfortable.


Well it depends. Usually 73 during the day, 75 at night. When it was 93 degrees the other day I turned it up to 80 because it had literally run from 8am to 3pm without shutting off ONE time.

Maybe I just expect to much. I just feel that an apartment only 1,100 sq ft should be able to be cooled to 73-75 without any problems. Especially with a freshly charged system and a brand new blower and a-coil. And ESPECIALLY when it's only in the 80's out. Now when it's in the 90's I can see it running quite a bit. But when it's 85, it should be able to cool a mere 12 degrees lower without running 12 hours straight without shutting off maybe once or twice..


I had similar problems, to be honest. I did the following, with amazing results, all of which you unfortunately can't do as a renter. Keep in mind that your dehumidifier is surely dumping warm air into your apartment that your A/C is now trying to remove.

1. installed 2 gable vents - HUGE difference
2. sealed all supply/return line joints with mastic (supply is in crawl and return is in attic)
3. sealed all return 'boots' to ceiling
4. regularly clean condenser every 2-3 weeks during peak usage and 2-3 times a year I hit it with simple green
5. adjusted damper valves in supply lines to balance/regulate supply across whole house

What type of filter is being used? I have experimented with filters (20x20x1) on my Rheem and the Ace & Menards cheapie pleated filters work best by balancing cleaning and flow. The expensive pleated filters definitely cut my air flow way down and the cheap fiberglass filters seem to have too much flow and the air doesn't exchange heat it seems with them.


Yea unfortunately I can't do any of the things you mentioned, just another reason I can't wait to get out of this apartment and get a house! I use a Filtrate Allergen filter. I have no doubts that it slows air flow but I also have absolutely terrible allergies year round. Allergist told me she's never seen such bad allergies in her career. So needless to say, the filter is staying for now until my immunotherapy fully kicks in.

 

[ctrcbob]

I see your unit is a "Goodman". I had new AC put in back in 2010. They installed a Goodman. Did not work right. (The Air Handler was good but the outside compressor was junk). After a couple days, they removed the outside unit and replaced it with another Goodman. Went through FOUR Goodmans. Air never came out cold enough plus they did not dehumidify the house. They then replaced the outside unit with an Amana. No more problems. The Amana works great. As far as I'm concerned, Goodman is another word for junk. Thank
god my AC contractor is great and stands behind his work.

 

[04SE]

Originally Posted By: ctrcbob
I see your unit is a "Goodman". I had new AC put in back in 2010. They installed a Goodman. Did not work right. (The Air Handler was good but the outside compressor was junk). After a couple days, they removed the outside unit and replaced it with another Goodman. Went through FOUR Goodmans. Air never came out cold enough plus they did not dehumidify the house. They then replaced the outside unit with an Amana. No more problems. The Amana works great. As far as I'm concerned, Goodman is another word for junk. Thank
god my AC contractor is great and stands behind his work.


When we got an all new system 3 years ago, I asked the guy (family friend with 30+ years of HVAC experience) about Goodman. I had to duck when he tried to smack me. He installed a Rheem for me. He all but refuses to work on them as he said they are junk. His comment was that they use dissimilar metals in their coils and cheap compressors.