HVAC Techs Battling Failing Systems

“First time hitting freezing temps here in CT. Many calls. Go to the first one for upstairs no heat. Hydro heat. (Boiler with a heat coil in the attic air handler) No voltage to the zone valve at the boiler. TO THE ATTIC!!! Zone panel showing no call for heat, of course the customer shut off the tstats….. why are people so dumb? How are you gonna have me try and find a no heat issue when the system isn’t even being told to make heat. Ugh. Long story short. Installers installed a new AC and of cou”

“I’m helping someone troubleshoot an Arctic Air AF23 commercial freezer (115V) that stopped working after a power outage. It was working normally before the outage but when the owner returned about a week later the unit was completely unresponsive. Here’s what we’ve found: - The green power switch illuminates when plugged directly into a wall outlet - The digital Dixell temperature controller remains completely blank - The interior light doesn’t turn on - Neither the fans nor the compressor start”

“AC has been off all day but for whatever reason the AC compressor and the lines are iced solid again. It was set to ‘off’ and fan on ‘on’, didn’t hear the fan inside but oddly the outdoor unit was running its fan. When we run the AC during the day with On/auto it freezes up as well What the heck is going on? lol submitted by /u/RemoteEmotions [link] [comments]”

“Yesterday it sounded like the AC compressor was coming on but couldn't feel any air coming out of the vents. Went outside and the condensation line (the pvc pipe with the p-trap) felt very cold to the touch and had condensation on the outside. So I figured that the compressor was working but the blower fan wasn't. Today I tested the dual run capacitor and it read 9.5 uF Fan to C, and 4 nF HERM to C. The label states 70+10 uF, +/-5%. This would indicate that the compressor side is shot, s”

“What could cause a system to run normally but no longer produce cool air. System was working fine yesterday but today the compressor and system seem to come on as normal but it is not producing cool air and there is no drip coming from the condensation pipe which usually has a pretty steady drip. Probably coincidence but we were having a couple brownouts yesterday. We maintained power but parts of town were out and ours flickered a couple times but never went completely out. Thank you!!! s”

“Im in Montreal Quebec and I have a York HMH72B341 that supposedly is low on refrigerant and is only putting out 24C on heat. The tech told me I’ll have to use emergency heat through this winter because the weather isn’t reliable enough to calibrate the new refrigerant. It’s been around 20C in the afternoons but cold at night, I’m skeptical that this can’t be fixed in the next couple of weeks in the afternoon. Should I call another guy or should I expect the same answers around this time of year?”

“Went to change my air filter and noticed a few things. 1. Cold air was blowing out from the area I patched with black tape. The sealant stuff was cracked open. 2. The area I taped was wet with condensation and there’s mold in several areas. 3. The clean out pipe doesn’t have a cap and cold air was blowing out of it too. What caused the sealant/glue to crack open? Should the clean out be capped? I made sure it’s draining properly, there’s not a clog. I’m fairly handy and do most repairs and home”

“Like the title says. It's currently 87 degrees (the same as outside) with the thermostat set to 75. It runs for a few minutes then shuts off for 10. Had been having trouble keeping up this summer, called 2 different ac techs and both said nothing was wrong with my system. I'm at my wits end and could use some advice. submitted by /u/natusexsol [link] [comments]”

“Maybe once or twice a year the coil in my air handler freezes over. I turn the cooling off and run the fan for about 30 minutes to melt the ice, suck out the drain line, turn it back on and it goes back to working normally. I have maintenance contract with a company every 6 months and they don't find any issues. Just a big head scratcher. Any ideas? submitted by /u/Yard-Ornament [link] [comments]”

“It’s currently 10:30 pm and i am sweating my butt off. I opened the ac unit thing and saw that my filter looks frozen. my AC completely stopped blowing air. i live in an apartment and there isn’t much i can do error maintance. we don’t have an emergency number either. it is Saturday night and they won’t be able to come until monday morning. please, what can i do for now? submitted by /u/Agreeable_Lobster585 [link] [comments]”

“Posted this earlier today. https://www.reddit.com/r/hvacadvice/s/373oTk2Ye0 While troubleshooting I noticed the AC buzzed/hummed while the main breaker was off. I think the breaker in the AC keeps tripping. We had a power outage yesterday and I am thinking that may have caused the issue. Would I need to replace the breaker or is there another underlying issue? submitted by /u/Dark_Knight556 [link] [comments]”

“Basically the title. Went outside to see what the issue could be and noticed this. Would this cause the issue I am experiencing? I’m am going to check the capacitor to see if that’s good. submitted by /u/Dark_Knight556 [link] [comments]”

“I have a Daikin Split in my ADU that I have a tenant in. The Split has stopped blowing cold air intermittently-starts and then stops. I have had 2 AC companies (Daikin Certified) come out. When one came out the unit was working so he said there was nothing he could do. The second said I needed a new motor but then did not return my phone calls about replacing it. They also said they couldn't find a motor- do they not want to deal with it because it is under warrenty? Frustrating. Collant is”

“I have a TCL 10k BTU unit to window by hose portable air conditioner. It’s the model # H10P36W. Within the last week it has been icing up within minutes of it being turned to the air conditioner setting. I’ve cleaned off the 2 back air filters. Could it be humidity in the room being sucked in and cooled? I don’t believe it would be that because we used it all throughout the summer and never had an issue. Used it pretty much everyday all night through the summer nights especially. Online it says”

“My central AC stopped cooling and I noticed the larger insulated refrigerant line outside had frozen over. I shut cooling off within about 30 minutes. The return filter was extremely dirty, so I replaced it, and the outdoor line has now fully thawed. The bigger concern is that the indoor blower will not run. With the thermostat set to System Off / Fan On, I hear the indoor unit click/attempt to start, but the blower never fully engages and I get no airflow at the vents. I opened the cabinet to i”

“I just moved into a house where the furnace, outside unit, and cooling coils were all replaced in 2024. I could tell the owners didn’t take the best of care on the appliances because everything froze over in late July, and I checked there was literally about an inch of dust on the outside unit. I also kept the house set to 68 and it was high 90s outside, so I figured it was partially my fault and the previous owners who didn’t clean it. I completely cleaned the unit, let everything thaw, and dec”

“Hey everyone, looking for some advice on clearing a cdrain line. System: 5 years old Day & Night 3 Ton AC system. Problem: Temp won't drop below 80°F, indoor humidity sitting around 79%. What I've Checked So Far: Checked the capacitor at the outdoor condenser reading solid at 44/5 against its 45/5 read on label. Checked the condensate drain line at the indoor furnace, and it is definitely clogged and backing up. Flushed vinegar and water down the cleanout last month and it ran fine t”

“Hi everyone. Sorry to trouble the community with a question but I have exhausted all other options trying to find information on this phenomenon. I noticed my AC could not get the temp below 81 in my house. Checked the airflow/filter. Checked the compressor. Checked the exchanger. No frost freezing issues. Everything appears to be working great. I noticed the suction line coming out of the condenser going into the house was “beer can cold.” Then went and checked the suction line entering the exc”

“Yesterday I called maintenance. They replaced the capacitor, transformer, and refrigerant. It worked for a little bit but today the temperature continues to go up. The thermostat is set to 73 and the unit is at 83. The fan is on auto and cool. Is it possible this is user error, or something easily fixed? I just changed the batteries in the thermostat. I just don’t like having maintenance in my unit if avoidable. But if it’s something that needs any kind of repair I’ll call them. Any insight? &#3”

“Got home this evening from being away almost 2 months.. System was frozen.. I've run the fan, melted it all and now it's dry and not dripping. Airflow was completely blocked on the vents and now it's coming back thru.. 14 yo system.. Time to replace and it's loud AF.. Even if it can be fixed, I was planning on changing during the winter when guys are looking for bidness..Oh well. Anyways Is it ok to run it tonight w a fresh filter? I'm in AZ.. Thanks.. submitted by &#32”

“I had the lower level AC ( coil and condensor) replaced 4 years ago. Recently about 3 weeks ago it seems to be taking a long time to cool down 1-2 degrees in texas heat which has been brutal this year. However this behavior was more apt for our upper ac in prior years as we have high ceilings and 5000 sq ft home ... I have gone through a lot of troubleshooting confirming c wire is connected at nest and voltages are ok. Also replaced nest backplate and front dial. Have turned off air wave and try”

“I replaced my central air/furnace filter on the 1st. Today I came inside and it was not cool. Found thermostat reading 76, set at 73. Lines had iced over. Currently thawing out but what else could cause that. Filter is not dirty, im thinking my blower may be slowing down? Is that something that is possible? It seems like an all or nothing thing to me. Air flow out of registers isnt blowing your hair around but its there. *thawed out and running again. Output side of blower is at 59, input side i”

“Outdoor unit fan is running just fine, but not hot air is coming out, and it keeps buzzing every few minutes, I assume it's trying to start the compressor. Visually the capacitor looks fine, but I don't have the right multimeter to test it. Should I just call someone at this point or is there anything else I can try? Is it worth just trying a new capacitor before calling, or just call at this point? Being a holiday weekend makes it worse. submitted by /u/OhWhatsHisName [link]”

“I’m in a 5 year old build. About 4,500 + basement but the last tech closed all but two registers in the basement, saying it would help push cold air up. This happened last year as well but when a tech came by, he said he had to recharge the AC because it was low. This year since Spring I’ve having the same issue and he’s come back twice to look at it/recharge the AC. It never got colder, even on cooler days. I’ll set the temp to 22.5/23 degrees Celsius and it will be stuck on 24 all day sunning”

“Hello I have this movicool pc7 portable unit. It threw an E4 code few days ago, I did a hard reset and it went away. But since then it's not cooling any more. Filter is clean, temp sensor is clean, no debris on any coils. Please look at photos attached, do they indicate a refrigerant leak, or what else could be going on? The freezing occurs within less than a minute of powering the unit. Please provide any input so that I can get this unit cooling again, if possible at all. Thanks. sub”

“I have 3 zones/thermostats in my house. Why might cold air be blowing in a zone with a thermostat that is off? My AC system occasionally behaves weirdly in this way. Zone A's thermostat would have a set temperature while Zone B's mode is off, but Zone B would be blowing cold air at times. I'm not very knowledgeable on AC systems with all their nuances. Any information is helpful and appreciated, thank you. submitted by /u/iPhillice [link] [comments]”

“Morning folks. Had some storms roll through all day yesterday and we experienced a power surge that I believe fried something in our AC unit. The outside unit is spinning fine, no odd sounds or hums. I shut the breaker off for 30 minutes for a hard reset and it didn't help anything. The units kick on and the fans blow but there's no cold air. I just pulled into work and didn't think to take pictures before I left home. Whaddya thinks going on here? Capacitor? If so, do the capacitors”

“Hey everyone, I live in a manufactured home and every year the condensate line ends up freezing / backing up, sometimes to the point of causing the furnace to stop running (I think due to a pressure switch being tripped?) I have went in the crawlspace and the only solution I see is to possibly run the condensate line into the main sewer line as opposed to directly outside as it is currently ran. I'm not sure who to call or how to tackle this issue due to the limited space between the sewer l”

“Hi all. Central AC question….. What does it mean if the expansion valve is freezing up within 5 minutes of turning on the system? Coil and filter are clean and there’s good airflow over the coil. I had to have the refrigerant topped off at the beginning of this season. Does this indicate a refrigerant leak somewhere or could it be the expansion valve going bust? submitted by /u/fasthackem1 [link] [comments]”

“My ac unit drain was apparently clogged landlord came over unclogged it, hooked drain pipe back up under the furnace, after it worked fine for a day or 2 then stopped cooling blowing warmer air out and the outside unit was not running. I unplugged the pvc drain pipe under the furnace and let it leaks into a bowl for the time being so I can have a/c. Plugged it back in went to work came home and now even when I unplugged the drain line the water wasn’t coming out anymore and air still blowing war”

“I was changing the air filter and it was dented and the filter got caught. Part of the cardboard ripped off and fell in. I cant get it out. The ac has still been on for like 3+ hours. Do I need to call maintenance? Is there a risk of fire? I cant find definitive answers online and I live in a building where the management is pretty uninvolved so don't want to ask for assistance if its not needed. But also don't want to neglect this if its an issue. Can someone help and let me know what t”

“What causes this? Is there a fix I can do to get it up and running? My house is miserable tonight. :( submitted by /u/Altruistic-Mango-847 [link] [comments]”

“I have a new to me house that has this old humidifier connected between the hot/cold air plenum and the cold air return. The water line isn't connected and the humidistat has also been disconnected. I plan on removing the takeoff from the plenum and the humidifier box from th cold air return and covering with a new piece of tin/tape etc. I guess I'm wondering how detrimental/how it will affect the system. It's basically straight feedback from the plenum to the cold air return and I c”

“We have an 18-year old HVAC system that’s had some issues over the past year and a half. Yesterday morning, the indoor unit completely shut off but the compressor outside was still running so we just shut the system down and called someone. The unit runs on R-410A refrigerant as well. Turns out, our capacitor on the indoor unit completely fried and the blower motor went as well. The motor has been making a weird clanking/squeaking noise for the past week. Our HVAC guy isn’t pushing us one way ou”

“I went up to replace the air filter because the AC had stopped blowing cold and we thought it might be an issue. As far as I could tell, looking through the machine, there was ice. Someone's advice was to turn the AC off but leave the fan on. We did, and cold, legit cold air, kept coming through for like a good couple of hours. Is this just leftover cool air in the ducts? Is this air being cooled by the ice on the coils? I can't figure it out, but the with the fan on but AC off, the hous”

“Long story incoming, I'm just so confused. We bought our house just under a year ago. We have a mini split (N80MSN, R4A4S and EVD4X are all the model numbers) that was functioning great the whole time. Husband and I like it cold and keep it 69 during the day, 68 at night. Never had an issue, swap out the filter monthly, everything seemed fine. 3 months ago I noticed the line outside was DUMPING water and was frozen closest to the outdoor fan, and the AC was just running 24/7 but barely cooli”

“My air isn't blowing out cold and there's little force coming from the vents. Im not sure if its frozen or not? If so, what do I do? Please help. submitted by /u/Far_Foundation1582 [link] [comments]”

“Our AC is not pushing out cold air like it did yesterday. We have changed the batteries on the thermostat, changed the filter, and let the ac stay off for 4.5 hours last night. Does anyone have advice on what the issue might be or suggestionsfor something that I would be able to check myself. Our house is 80 degrees at night and even hotter during the day. submitted by /u/Remarkable-Bug4552 [link] [comments]”

“Hey everyone, my AC unit went out yesterday. It was still circulating, but not blowing cold air. I ended up replacing the capacitor with a Titan HD part from Home Depot. That lasted about 1 day. So, not sure if I got a bad capacitor from Home Depot and I should attempt to replace that again. Or if there's a much larger problem. Any insights is appreciated. submitted by /u/edddduhhhh [link] [comments]”

“System Specs: Outdoor Unit: ICP/Carrier 2.5-Ton Condenser (Model: R5A5S30AKAWA, R-454B) Indoor Unit: Day & Night Air Handler / Coil Installed: March 2026 (Pre-charged) Background & Timeline: 1. System was rarely run during spring. 2. 3 weeks ago, started major home renovations (floors, drywall/paint, popcorn ceilings). 3. Tradesmen ran the AC at 68°–70°F with exterior doors propped open. 4. AC was then shut off for a week during final flooring install. 5. Deep cleaned the house and pulle”

“Should the second PVC from the left be capped? I believe the first one should be. And the one on the far right should be uncapped. Im trying to figure out why im getting this persistent condensation on the middle part of my unit and im wondering if there is some kind of internal air restriction. submitted by /u/heyitspriddy [link] [comments]”

“Okay. This is my 4th time here. 3 months ago I noticed my AC wasn't cooling super well. It was running 24/7 and still above the set temp. I posted here, somebody pointed out that the pipe outside was frozen which could mean low freon. Had a tech come out, he agreed on low freon, said there was a leak, and in 30 minutes was in and out and it was supposedly fixed. He never went into the attic to check for attic leaks, just to clarify. 31 days after he visited, it happened again. I did what you”

“Our Wall unit is completely frozen, from the top to the bottom of the vents. Filters are frozen into the ice. At the time of posting, AC hasn’t work in 4 days to thaw… but clearly that’s not working. Any idea what could possibly trigger this? submitted by /u/atcha_boii [link] [comments]”

“My AC unit stopped cooling. I cleaned and vacuum the outside unit. I also vacuumed out the drain. The shop vac was filled with that goo. When I put back in the outside shut off there was no power. There's power at the main breaker, and at the unit in the attic. My question long story short is there a fuse or switch I'm not stopping power from going outside? submitted by /u/like_if_KD_ruinedit [link] [comments]”

“About a month ago the power went out and when it came back on the thermostat was dead. I changed the batteries, but the air wouldn't kick on. I went to the roof to check it out and as soon as I touched the drain pipe it turned on. Every now and then the ac will shut off and I'll go to the roof, hit it, and it'll turn back on. What is the issue. submitted by /u/No-Violinist5217 [link] [comments]”

“3 days ago, I noticed my AC was at 71° with the thermostat set to 68°. I checked the outdoor unit and found the compressor frozen. I shut it off, changed the dirty filter, cleared the ice off the compressor with water, checked the attic pan/drain (both good), and restarted it. It cooled fine for about 24 hours before struggling again. I called HVAC and was told the attic coils may not have fully defrosted, so I ran the fan only for 8 hours. After restarting, it struggled to keep up but eventuall”

“So I rent and our ac went out so it’s currently 80 in our home with a baby, landlord said he’s not calling an emergency hvac to come out we’ll have to wait till tomorrow. The motor or whatever it is inside the outside unit and the line set running off of it and into the house is frozen solid. The fan will run but I get nothing inside the house. I checked the air return and vacuumed it but I don’t know what else to do, TIA submitted by /u/Novel_Ad1567 [link] [comments]”

“In the evenings, I noticed the house temperature actually increasing. I went outside and noticed this line has a lot of ice on it, even under the foam. I did replace the filter, so it’s brand new. A one man band hvac tech said the system is fine, but I know he didn’t t get in the attic to check the unit so I am not sure on his opinion….should I have another reputable company check it? Ideas? Tia submitted by /u/Elpadre83 [link] [comments]”

“I believe I have a positive pressure hvac. Do I need to put a cap on the 2 white caps to prevent cold air from releasing? submitted by /u/TitanColaberry [link] [comments]”

“We've been having a heat wave upwards of 106 recently and during the hotter days the ac unit stops blowing cold air. I checked the outdoor unit and didnt hear any noise and saw the fan wasnt moving either. This typically lasts until the sun goes down and then it starts working again only to fail again around 4-6pm. What can I do to fix this issue? submitted by /u/Main_Conclusion_6714 [link] [comments]”

“My A/C is in my garage and in humid weather it collects condensation that drips and makes a mess. Can / should I wrap this in insulation or will that result in soggy insulation? Also, how? I only have access to 3 sides. submitted by /u/ElevatorFlatulator [link] [comments]”

“Had a 27 year old 4 ton system running fine last week. This week outdoor unit iced up like hell and air temp coming out of the registers was equal to the outdoor temp. Tech said he could recharge but due to the age of the unit it could be 600-700 bones (Less than what I was expecting tbh). He seemed honest and gave me a several options. I opted to due a full replacement because the old unit was a bit shit, and the gas furnace was just as old. I took the 4 ton enhanced efficiency option at $12,42”

“Had no A/C for about a week. Just got a new central unit installed today. It’s set to 67 but the temp won’t go below 69. It’s been a few hours and it’s holding steady at 69. What could cause this? submitted by /u/CrueDude18 [link] [comments]”

“I moved into my new apartment a week ago and last night i noticed that the temp did not drop when the sun went down. Normally I set it to 75° during the day (I am in south texas and it was around 97° yesterday) but at night i set it between 68°-70° (nighttime temp is between 76°-82°). Last night the thermostat was set to 70° and the temp was 77° when i woke up sweating in the middle of the night and it was only 2° cooler than outside💀 I’ve never had a wall unit like this before but does this lo”

“Where the aluminum tape is, there was cold air coming out of little openings from what seems like a poor quality install with the handler. The air goes up into the air ducts in the attic. Will that make a bit of difference or am I wasting my time? submitted by /u/Marcotaco18 [link] [comments]”

“First time homeowner here so please go easy on me! My HVAC drain lines are clogged which is causing the float switch to trigger and shut my AC off for a couple of hours at a time. How should I drain the water? Bring a shop vac up to the attic and suck the water out? I’m also having trouble determine which pipe is the drain line for my AC on the outside of the house. The black pipes run to the right side of my house and there’s 2 pipes by the foundation. The white PVC pipe runs to the left side o”

“Hi all, Blower motor went out over the weekend, so I replaced the motor yesterday morning and the AC was running. Our house was very hot without AC, so I took a WHILE to catch up and cool off. The unit is 17 years old, so I was looking up how to maintain it and figured if clean the unit outside. I sprayed it with a foam AC cleaner solution and then rinsed it. The power was off and I restarted the unit within 5-10 min after rinsing. Fast forward 8-9 hours and the line from the outside unit coming”

“2 days ago, my AC was struggling. Filter was dirty and being sucked into the blower. Changed it Fan was working. Just no cold air. Looked outside, there is ice on this as well as the rest of the copper tubing on the inside. Let it thaw out, and turned AC back on. It worked wonderfully. Now AC unit is struggling again Please point me in the right directions, Im a new home owner and willing to learn how to fix all my stuff as techs can be very expensive submitted by /u/Ok_Breakfast_733”

“My house was built in April 2021, last year the compressor blew and last week 1 of the 2 zones (thermostat 2nd floor and another on 3rd floor) was struggling to reach the desired temperature. I had my HVAC guy come and checked the coolant on my system and it was all good. He then asked me what filter I use and I told him I get them at Costco, 16x25 on the 2nd floor and a 20x30 on the 3rd floor, system in attoc doesn't take a filter. HVAC guy immediately said that it's no good and to chan”