I’m having an issue with my central AC. It cannot seem to get the temp down to where I would like it - 71 degrees. Last night when I got home from work the temp in the house was 76 (AC was turned off all day). I set it to 71 and it ran continuously for 6+ hours before it could get the temp down to 71. This has never been an issue in the past. It could always get the temp down to where I would like it in a short period of time and then after that it would cycle on and off to maintain. There is cold air coming out of the vents but I’m not sure how cold it chould be as I never really paid attention to this before.
The AC is a Rheenm and is 3 years old. I checked the cold air returns and they are clean and the furnace filter was replaced last night after the unit was running so long even the the old one looked ok. I’m about to call the HVAC people but just wondering if there is anything else I can check?
I had a similar problem three months ago in our new rental. The thermostat on the heat pump was set to 68, and despite the unit running non-stop for literally weeks on end, the temperature never crept higher than the low 60s, and we never actually felt warm air blowing from the events. A tech came out to look at it, and found that some sort of relay switch between the heating and cooling mechanisms in the outdoor unit was malfunctioning, allowing both to run consecutively. They replaced the relay switch and we’ve had no problem since.
I’d think a a quick call to Rheem should point you in the right direction.
The HVAC guys are going to look at the most costly things first, the compressor motor and refrigerant charge. These may be the case.
First, I would walk around to all of the vents to see if you have good air flow at all of them. I’ve seen several cases where ducts have actually become disengaged and all that cold air just goes into the crawlspace or attic. Also check your return air vents. Are all the vents fully open?
Go outside when the compressor is running and put your hand in the stream of air that is coming up from the fan. Better yet, use one of those digital meat thermometers. If you have enough refrigerant in the system, the air should be > 100 degrees F, around 120 degrees IIRC. If it’s only slightly above ambient, you need some refrigerant.
How hot was it where you live? Hotter than usual? Was the house very warm inside when you turned the unit on? Do you live in an area where there is a lot of cottonwood trees?
The outside unit (condensing unit) could be plugged up and unable to reject the heat outdoors. If it’s 3 years old, you are most llikely not low on refrigerant. How dirty was the filter
that you replaced? Joe
How hot was it where you live? Hotter than usual? Was the house very warm inside when you turned the unit on? Do you live in an area where there is a lot of cottonwood trees?
The outside unit (condensing unit) could be plugged up and unable to reject the heat outdoors. If it’s 3 years old, you are most llikely not low on refrigerant. How dirty was the filter
that you replaced? Joe
Its been hot and humid. 85+ degrees. The unit was turned off all day so it was 76 inside the house when I got home. This is not unusual though. I typically leave it off for the day and the unit has no problem cooling everything down in an hour or so. It was working just fine earlier in the week. No Cottonwood trees but I am going to take a closer look at the unit and see if anything is clogging it up as well as some of the other ideas suggested.
Do you have interuptable power on the AC unit? If so, even though its not that hot yet, your utlity could have been caught up short on generation capacity early in the season and had to trip it.
Go outside when the compressor is running and put your hand in the stream of air that is coming up from the fan. Better yet, use one of those digital meat thermometers. If you have enough refrigerant in the system, the air should be > 100 degrees F, around 120 degrees IIRC. If it’s only slightly above ambient, you need some refrigerant.
The air coming up from the fan is around 88. Ambient is around 84 so maybe I do need refrigerent.
What about the cool air coming out of the registers inside? It reads around 60. Shouldn’t that be cool enough?
The air coming up from the fan is around 88. Ambient is around 84 so maybe I do need refrigerent.
What about the cool air coming out of the registers inside? It reads around 60. Shouldn’t that be cool enough?
You’ve almost seen the sum of all my knowledge on the subject, but I think that’s just a tad “warm” for the cold air ducts. You’re shooting for an 18 - 20 degree delta in temperature. I think the smoking gun is the inability to properly reject the heat outdoors. When you measured the temperature of the hot air, I assume you had the thermometer dangerously close to being hit by the fan blades, right? That was my intent, but I’m not sure if I mentioned it quite that way.
The air coming up from the fan is around 88. Ambient is around 84 so maybe I do need refrigerent.
What about the cool air coming out of the registers inside? It reads around 60. Shouldn’t that be cool enough?
You’ve almost seen the sum of all my knowledge on the subject, but I think that’s just a tad “warm” for the cold air ducts. You’re shooting for an 18 - 20 degree delta in temperature. I think the smoking gun is the inability to properly reject the heat outdoors. When you measured the temperature of the hot air, I assume you had the thermometer dangerously close to being hit by the fan blades, right? That was my intent, but I’m not sure if I mentioned it quite that way.
Yeah, I put the digital therm as close to the fan blades as possible. Thanks for all the info. I’m going to see if I can get a service tech to come out later today or the weekend.
Fatmouse always give good insulation advice. good idea to check for supply that came loose.
go outside to condenser. make sure fan is running if not SHUT OFF. There are 2 copper lines going into condenser. check the larger one that is covered in black insulation. It should be “beer can cold”. if not you probably are low of refrigerant. it if is hot or frosty then you have issues SHUT OFF.
HVAC tech was over today. Refrigerent was low so he re-charged. Also ran a leak test and fixed that as well. All should be good now.
i just saw your post and that is exactly what i was gonna say, low on freon. run that system any longer while low on freon (if r-22, r-410A is puron, not freon) and your evaporator coil would’ve turned to ice. keep that filter clean/new. huge alterations in system performance in regards to a clean or dirty (blocked) filter, your system will freeze up as well if clogged, ice.
The HVAC guys are going to look at the most costly things first, the compressor motor and refrigerant charge. These may be the case.
First, I would walk around to all of the vents to see if you have good air flow at all of them. I’ve seen several cases where ducts have actually become disengaged and all that cold air just goes into the crawlspace or attic. Also check your return air vents. Are all the vents fully open?
the hvac guys are gonna tell you what is wrong and this is a case closed low on freon scenario, without having to be there with my gauges on the system. very typical and I’m 100% sure that the leak in west side’s system was an installer weld gone bad, not a product weld, not at three years of age.
that scroll compressor will out live a turbo diesel engine ( not really but at least ten years and I’ve seen residential compressors last 20+) and those limit switches are designed to protect your compressor, no way a it would’ve grounded out so soon.
Fatmouse always give good insulation advice. good idea to check for supply that came loose.
go outside to condenser. make sure fan is running if not SHUT OFF. There are 2 copper lines going into condenser. check the larger one that is covered in black insulation. It should be “beer can cold”. if not you probably are low of refrigerant. it if is hot or frosty then you have issues SHUT OFF.
best of luck
when a system is really low on freon the low side aka the suction side will turn literally to ice as will the evaporator coil and freeze up so you are giving incorrect information, just letting you know.
Make sure the evap coil isn’t coated in hair, ice, etc.
have an installer cut in an access door on the top of your transition to get to your coil or you will be pulling your tranny apart and then you are screwed if you don’t seal it back right. on second thought, don’t even attempt to open up your system yourself, call a company.