New Central Ac Unit Runs All The Time During The Heat Of The Day

by Vickie
(Ohio)

We just purchased a 3 1/2 ton Goodman central ac unit at the end of May. We had a service tech do the Freon and silver solder the lines. We also purchased a new Goodman furnace and A-coil in November 09.

We went on the advice for size for both from the heating and air wholesaler we purchased our central ac units from. Our home is approximately 1600 square feet and we have 13 registers. We also purchased a new thermostat.

We've never had Central air conditioner before. Our new central ac unit runs constantly during the heat of the day, usually from about 2pm till 9pm in the evening. Granted, it's been hot here, mid 90's and the heat index higher. Do we have a problem or is this normal?

My husband thinks our duct work may be too small for our new central air conditioner system. Our home was built in the 60's and we used our existing duct work. Thanks so much for any help you can give me.

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Rating
starstarstarstarstar 		Crazy AC system
by: Anonymous

What happens if you set it at 74-75 and the temp says 80-82 the whale time it runs.? It does not shut off till around midnight. This is a new system. Do you need to replace the blower unit if you just replaced the outside unit?
Rating
starstarstarstarstar 		many things to consider NEW
by: David

Any of these will cause your AC running non-stop and not to keep your set temperature:

1. Your air return window (grille) is too small. 3.5 ton AC needs 700 square inches of air filter area.

2. Dirty air filter
3. Blower in furnace must support 1600 CFM (1 ton of AC need 400 CFM)
4. Attic air leak. You need to climb up there and seal all air leakage passages. I sealed 14 small and large attic air leaking spots in my house.
5. Large window facing West should be covered with blind and/or tint them with head control film
6. Weak insulation attic. Adding more insulation if it is too thin up there.

7. Round duct size should be 18' or more for 3.5 ton AC.
Rating
starstarstarstarstar 		apartment ac question NEW
by: Anonymous

i have a 1 1/2 ton goodman heatpump system and my problem is my unit runs all the time.
my house is like an ice box unless i turn it off
i have a new filter and am out of ideas
Rating
starstarstarstarstar 		Perplexed NEW
by: Hal

I have a Lennox central air-unit with Programmable thermostat. When it os on the sleep and leave settings it cycles on and off at 15 minute intervals. When it is in return mode, even one degree drop, it runs almost continuously. It reaches the temperature setting but runs after the setting is reached. The installer has checked the system and finds nothing wrong.
Rating
starstarstarstarstar 		Thermostat NEW
by: Anonymous

Should fan on thermostat be set on should fan thermostat for ac/dc set on auto
Rating
starstarstarstarstar 		Thermostat NEW
by: Anonymous

Should fan on thermostat be set on should fan thermostat for ac/dc set on auto
Rating
starstarstarstarstar 		annoyed NEW
by: Anonymous

Just got a new unit and everything an mines doin the exact same thing I have free service if it doesn't work right I'm gonna keep calling til they figure it out I'll let u no!
Rating
starstarstarstarstar 		annoyed NEW
by: Anonymous

Just got a new unit and everything an mines doin the exact same thing I have free service if it doesn't work right I'm gonna keep calling til they figure it out I'll let u no!
Rating
starstarstarstarstar 		AC runs all the time NEW
by: Anonymous

Vickie, Dadan,

Did anyone find a solution to this issue?
Rating
starstarstarstarstar 		Central Ac Run All The Time NEW
by: Tommy

Vickie & Dandan

I have the exact same problem. I live in an apartment and the maintenance guys are stupid. They tried to tell me it should run constantly. My bill has double and I know it will be more next month. It runs from 2:00 to about 8:00pm. They replace the unit twice but still the same problem where the AC runs constantly for those time frame. I have decided to research it myself and find out what the issue maybe. My thermostat is set at 76 but during the time frame above the temp reaches from 78-80 on the thermostat. I thought it had something to do with the oven being on. I say that because I noticed when it on the temp goes up on the thermostat, which is expected if oven is on for long period of time but the oven is only on for about 10-15 minutes. The theory when out of the window when I left the oven on for about two hours and nothing happened. I will continue to search for a solution and post any update that might be useful.
Rating
starstarstarstarstar 		Help NEW
by: Dinene

Turned my air on, it ran for three days without shutting off. Ran constantly. I turned it off and tried it again today. My thermometer I taped up near the thermostat reads 78 degrees. The Thermostat reads 70 and it is set at 78. It Has been running non stop for 5 hours now. Why? It is not cooling down hardly at all. Landlord sent some here today and he said he put Freon in it. I now this isn't right to run this long and the different temperatures on my thermometer and the thermostat. My bill will be outrages! Why if it is set at 78, reads 70 and runs so long not cooling down.
Rating
starstarstarstarstar 		HELP NEW
by: Anonymous

Turned my air on, it ran for three days without shutting off. Ran constantly. I turned it off and tried it again today. My thermometer I taped up near the thermostat reads 78 degrees. The Thermostat reads 70 and it is set at 78. It Has been running non stop for 5 hours now. Why? It is not cooling down hardly at all. Landlord sent some here today and he said he put Freon in it. I now this isn't right to run this long and the different temperatures on my thermometer and the thermostat. My bill will be outrages! Why if it is set at 78, reads 70 and runs so long not cooling down.
Rating
starstarstarstarstar 		To 2 ton heat pump
by: Anonymous

It sounds like your heat pump unit is too small for your house.

This could also mean, that is a lot leak within your residential and this could the heat pump to not have the capacity to remove all the heat from the indoor.

The best option is to ask technician to look at it and find out the reason.
Rating
starstarstarstarstar 		fan running all the time
by: Anonymous

just got a new 2 ton heat pump unit and the fan runs all the time and never kicks off. Could this be a problem with the thermostat? It kicks off only when I go and move the thermostat up?
Rating
starstarstarstarstar 		Possible Not Correct Size
by: Anonymous

It sounds like your central air units couldn’t deal with the heavy heat and it was not proper size central ac units.

Why don’t you ask hvac company to do a load calculation.

Dadan
Rating
starstarstarstarstar 		Puzzled
by: Be side myself

My central air unit has started acting very funny lately, during the heat of the day, it does not cool the apt, and it runs non-stop, then when the sun goes down, it starts cooling and cycling properly. I've had 2 separate companies, check the system, and they find nothing wrong with it.
Rating
starstarstar 		Good A/C Unit vs. Old House
by: B.E.K.

Many of the houses built in the 60's as yours was had little, or no insulation at all. I've found this to greatly affect the heating, and cooling of these structures. Also, if you are using the original, rigid metal heat ducting then 1.-It is too small. 2.-It probably doesn't have any insulation left on it which means that it WILL be super-heated by the high heat in the attic, will sweat (alot!) - this can eventually cause sheetrock damage, wood rot, mold, or could provide a nice damp area for termites. You might have purchased a good (or great)air-conditioner system but, need to seriously focus on your home. GET A PROFESSIONAL INSPECTION - QUICK!!!
Rating
starstarstarstarstar 		A/C runs all the time
by: wood

First check the T-stat setting. If it is set way below the actual air temp. it will continue to cycle a/c unit until set temp. is achieved at T-stat. If the temp. in your house does not cool efficiently there could be other problems associated with your cooling system. Condenser sizing, supply and return air duct sizing, dirty coils (indoor and outdoor coils), check air filter for clogs and excessive dirt build up, this can cause return airflow problems. Indoor coils can be clogged with dirt not allowing air to flow through coil to remove humidity and air to pass through cold coils. check TXV adjustment and proper placement of bulb. Duct sizing is imperative to system efficiency. Refrigerant levels determined by superheat at outdoor coil. Low refrigerant (FREON) can cause indoor coil to freeze up so air cannot pass through coil. The A/C system is integration of refrigeration and air flow with many components that must operate efficiently. For example indoor fan speed changes from cooling to heating. Hire an experienced HVAC service tech. that is how you will get your $$$ worth.
Rating
starstarstarstarstar 		answer
by: Anonymous

heating ductwork is normally smaller then ac duct work because you need more airflow for ac have someone check the air flow statis presure
Rating
starstarstarstarstar 		Runs all the time
by: Anonymous

A properly sized AC unit would run constantly during times of maximum load. Check the thermostat.

If actual temperature is still above your set point, then the unit should be running! Once it reaches the set point at some point it should start to cycle on and off.

But on your hottest days, it should be mostly on. If your unit cycles during lower demand times, then it is probably just fine. If the actual temperature is below your set point, then there is something wrong.

It is just as important to have an AC unit that is not too large as too small. Too large and the AC will drop the temperature, but not have time to dehumidify and you will feel "clammy".

Air gets dehumidified by the air flowing over the cold coil and water condensing on the surface of the coils. When purchasing a modern unit, a unit that allows you to set humidity as well as temperature will save a great deal of money, because you can set the humidity low, and be just as comfortable at a higher temperature.

Well worth the extra cost (is actually a bargain), and you will be more comfortable. If your unit is sized to run continuously on the hottest days, then it is sized right and should be doing a good job at humidity control.
Rating
starstarstarstarstar 		Central Ac Run All The Time
by: Dadan

Hey, Vickie

I’m not sure what you meant by “all the time.” If it run nonstop, that is not normal. It normal for central ac unit to run and stop for like 8 or 18 minutes and then it come back on. (8 and 18 minutes is made-up number, sometime it less and other time it more.)

I had seen this thermostat that had hold button. This button allows your central air conditioner to run nonstop until something causes it to stop. I don’t recall the thermostat branch. This
thermostat is digits screen by the way.

Had the contractor look at the ductwork? I can’t tell you if it too small for your new central air conditioner units. It not normal for central air conditioner unit to run nonstop, until you had this thermostat.
Regards,

Dadan

P.S come back here if I didn’t answer your question correctly.

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