HVAC System Troubles & Maintenance

“I have an original Sigler that came with the house 1930s. It’s gas powered. The fan is making a weird noise. Should I leave it on or off? submitted by /u/Status_Leg_6432 [link] [comments]”

“I've read through some posts on here and not sure if I have a clear, experienced answer. I've got an older AC system in our attic, climate zone 6, and there is a large, powered vent that I'm not even sure works. We're looking to have our roof redone and I'd like to remove that vent but I don't know how to go about figuring out if I need it. There is ridge vent & a cupola (which I'd also like to remove), right above where the unit is located, and our eave soffit is”

“I live in a 4 year old condo and my fancoil / hvac closet has a really annoying humming sound when the thermostat is set to active cooling or heating. When active cooling or heating is not happening, the vents still blow air and there’s still a slight sound but it’s not as bad (but still annoying) Is there anything you experts think I should ask a technician to check? I’ve had one guy out from 4seasons who came in and said the noise was normal and didn’t even open the unit. The weird thing is th”

“Last season, our attic fan stopped spinning up to full speed and I just presumed it was an old motor going out. Fast forward and now I’ve replaced the motor, bypassed the speed dial, and replaced the timer switch and the behavior is unchanged. The motor turns on and spins, but it spins way slower than it should. Im confident in the wiring, the motor rating, and the capacitor. Wondering if there’s anything obvious to you that I’m missing or if just somehow, somewhere in the line all of the power”

“Whenever I turn on AC or heat, the fan struggles to start. It only makes a rumbling noise every 10 seconds or so but then it'll eventually start spinning normally after 3-10 minutes. As a result, I start the fan up by itself and wait until it's spinning before I turn on AC. At this point it seems to behave normally. It's a Trane XV80. I've tried searching but haven't been able to find my symptoms. It's not a consistent humming, so I don't think it's the run capaci”

“Hey guys and gals, my thermostat only lets me turn it on/off, change from heat to cool and adjust temp…that’s it. It won’t let me control fan speed, if I even can. Is there a way to access more features on the thermostat screen? Also, I’ve had these Vert-I-Pak units before in a couple apartments and I’ve never heard one this loud. It sounds like a jet engine at the air intake areas. Took off the filter and no difference. Any help is appreciated! submitted by /u/CANFOR99 [link]”

“My apartment has had some issues with the heating turning on randomly while the ac is set to cool. Luckily the first 2 times it had happened I was home and I noticed it fairly quickly. Both times the outside temp was about 65-70. First time this happened I was asleep and woke up to my apartment being 90 with it being 60 outside. Unfortunately the third time it happened, I was at work. I have 2 cats at home and I came home to my apartment feeling like 110 degrees and my thermostat maxed out at 99”

“TL:DR - My Air Handler runs the fan constantly no matter what. I cannot figure out why for sure, but my best guess right now is the Blower ECM control Module Hey guys. I'm having an issue with my home's central HVAC that I've been trying to fix myself for the past 3 hours. I have included photos of my unit's outer label, motor label, and some of the key wiring spots. Here is a summary of my system: Builder grade Carrier system from 2016, 5 Ton Air Handler, 3 Ton Compressor. Air H”

“Hi friends, first time homeowner, so there's a lot for us to learn. We purchased this renovated home with a new HVAC system installed in the attic. We're working on getting our home more efficient. I've taped up leaks found around the unit with foilmastic. While up there, I noticed cold air blowing out of the condensate drain. I went to Google and learned that I needed to add a tee-ed vent after the p-trap and cap the clean-out before. After finishing that, no more air was blowing ou”

“You need to get boxfan and out it in the door way. But - - and this is important- - you do not want to blow cooler air in you want to be sucking the hot air out so point the fan to blow out of the room. A greybeard taught me this trick years ago. I thought he was out of his mind when he pointed the fan in the "wrong" direction, but it was surprisingly effective.”

“I have this electric furnace. Normally I run the fan from the thermostat with the setting “fan on” throughout the day to circulate air in my house. I had always had the fan setting on the furnace here (switch on the left - speed selector) set to “low”, but all of a sudden the fan doesn’t work in that specific setting anymore (thermostat clicks - fan doesn’t come on). BUT the fan still works if I turn the speed selector switch to “high”, and the fan still kicks on if I turn the heat or A/C on. I”

“We’ve noticed too high humidity in our bathroom and we’re not sure if it’s because of the bathroom exhaust fan needing replaced due to a weak motor, how the ducts are set up, or something else. Additionally we noticed some microbial growth in the attic rafters that were getting remediated, and we’re not sure if the duct work is contributing to it or if it’s more of an attic/roof venting issue. Should we replace this plastic duct with insulated metal duct? Could the current duct work be causing m”

“I just moved into a new house and I’m baffled by what these switches are and what this vent does. Anyone here know? submitted by /u/rileymcshane [link] [comments]”

“My inlaws called me because their furnace wasn't heating. It was just working last week, so I gave it a quick look. Noticed it was humming a bit. Shut it off and opened it up. Gave the inducer wheel a little spin. Felt a bit gritty, but spun freely. Started it back up and fan spun on its own. Sounded like a bit more grit worked its way out, then sounded smooth. Anyone ever experienced this before? Where do you think it came from? Anything to worry about? In laws are snow birds and don't”

“It’s not full of water, I drained it. Is it hitting something? submitted by /u/thisismypornaccountg [link] [comments]”

“Posting again b/c for some reason pictures were not attached in the original post ‐------------ My indoor humidity levels are huge... so I went up to check my AC and found an open pipe blowing cold air into the attic... Is this normal? Just an ignorant new home owner here submitted by /u/CompleteGur4491 [link] [comments]”

“Our HVAC system starts blowing hot air through the vents during hot weather, and there's no way for us to turn it off unless we disconnect some power (haven't tried). Is this normal behavior? This didn't suddenly happen; it's been like this for as long as I can remember, and I always thought the system was trying to cool itself down. I checked the thermostat, and it looks normal (AC off, fan set to Auto). We replaced our antique thermostat with a Nest, but it’s still doing the sa”

“We recently had 2 attic fans replaced. In the past, one had a humidistat and the other a thermostat. Now both have both settings. I don’t know what the electrician set them to. It has been humid and the fans are running continuously. A heat/humidity monitor I put in the attic shows the humidity to be at or just below the outside (currently 87%). What should the settings be to avoid having the fans run continuously due to high outside humidity? Should the settings be set so one responds to heat a”

“My unit outside in the metal box won’t stop spinning even when I turn my mode to off instead of “heat/cool”. It just recently started doing this. The outside unit usually shuts off the fan the moment my indoor thermostat hits the specified temp but now even when the mode is off the outdoor fan keeps spinning. I went outside to pull a lever from on to off which stopped the fan. But the moment I pull it to on the fan immediately starts spinning again. Bad contactor? submitted by /u/ome”

“So annoyed my outside AC unit when it was really hot about two weeks ago my fan stopped spinning and hot air was coming into the house. When the AC unit would cool off and or I water it down it would turn back on and blow cold air. The AC guy comes out checks everything just my luck the next day it was cool and breezy so of course the fan was running without issue he’s everything looks to be working fine to me I told him how the fan stop spinning at the hottest part of the day. He then put in mo”

“I've got a FV-16VEC1T Panasonic BalancedHome ERV that I want to interconnect with my Carrier 59P6B080V17 furnace. My understanding is that the fan signal from the thermostat is supposed to run into the ERV, then back out on another wire to the furnace (Gf), that way the ERV or the furnace can call for fan. I set up the wiring consistent with the ERV's diagram as follows: Furnace R to ERV R Furnace C to ERV C Thermostat G connected by WAGO connector to ERV G ERV Gf to G on the furnace boa”

“Noticed my attic is cooler than it should be and worried that my ducts might be leaking. I’ve been trying to look for cold air leaks and found this. Cold air is blowing up from the higher vent pipe (then the lower one if I cover the higher with my hand). Is it plumbed correctly? There is also cold air coming out where the refrigerant gas line enters the unit. I assume I should put some foil tape or something around that air leakage? Thanks! submitted by /u/Open-Practice-3228 [link] &”

“Noticed a couple days ago the water heater was making a weird sound but didn’t think much of it. Figured it was just something that happened but I hadn’t been around to hear it before. Last night, I went to check it just to see after showering because I knew it would be on, and it was making that sound again as it was trying to heat water. Noticed the fan wasn’t on either and it always turned on when heating previously. So figured something was definitely wrong. Stayed there for a bit and the fa”

“I have some concerns with the idea as it may pull in more humidity into the home or cause energy loss through ductwork however there could also be an increase in comfort. What’s your guys opinion? submitted by /u/JAWSMUNCH304 [link] [comments]”

“Temp inside home was 80 degrees and noticed that my fan was not spinning in my outdoor unit. Walked outside and heard a humming sound then stopped. Im leaning capacitor. Problem is, I have two caps. One slimmer and the other a bit larger. How do I know which one is bad without testing? Above are two photos. Thanks in advance! submitted by /u/Rolltide201278 [link] [comments]”

“Apartment AC is set to Cool and thermostat says “Cooling,” but there’s usually little/no airflow. Every so often the fan kicks on and blows cold air for ~1 minute, then stops again even though the room is still above the set temperature. I’ve tried lowering the setpoint, restarting it, resetting the breaker, and setting the fan to run continuously. Same issue. Any idea what this points to? Blower/control issue, safety switch, frozen coil, etc.? submitted by /u/Jeetyetdude_ [link] &#3”

“Fan making noise but not spinning. A few weeks ago I had been getting high refrigerant alerts. HVAC guy said it was very dirty so I had the outside unit thoroughly cleaned and haven’t had the alerts since. Now it’s doing this. The unit is only 4 years old. submitted by /u/Mm2789 [link] [comments]”

“So the first floor HVAC is in attic above 2 nd floor. It’s 4 years old Armstrong single speed. It been very quiet till now. It blows fine so why would it suddenly get noisy ? It seems to come from return air duct in master bedroom I took cover off and spun fan by hand . It spins smoothly, no play no obvious blade issues. I read even these simple system now have ECM motors and controller’s? Suggestions please it’s bugging wife. Would it be worth it to call out a service tech ? submitted by”

“Just found out the extractor fan in the ensuite is leaking. I moved in recently (4 mo) and this particular fan never worked since but today I heard dripping noises and saw this. Checked the attic and apparently this fan is placed right below the cold water storage tank, which is really worrying. How fecked am I? submitted by /u/Tricky_test9513 [link] [comments]”

“I'm a newer homeowner with an AC different than the rental I lived in. When the AC is running, air blows out of the far left pipe. Should this be capped or is this an exhaust function? I was told in a previous post its a secondary drain line. The line with the funnel is also not capped, but no air coming out of it. Secondary, when i rain vinegar and then water thru the 1 with the funnel for maintenance, no water exited the drain at the outside, a couple cups total. Im assuming this isnt good”

“~SOLVED~ Changed out the capacitor (new one is an amrad, same spec) because I have one but didn’t help the issue. Makes the noise in the video with the new capacitor, not with the old one. Bad fan relay? I did have it replaced about a year ago. submitted by /u/ElongatedHorseConch [link] [comments]”

“I live in the desert, 1500 square feet and 9 foot cielings. I’m looking at the quiet cool models. My house is only 10-15 years old and I’ve checked the venting access my attic has. Seems it could handle sizes up to the 5k CFM. What size unit should I ideally be getting? submitted by /u/hpsportsfanatic [link] [comments]”

“Hi, Just had a new American Standard 2 stage, variable speed furnace installed. I have central air, but didn't replace it. The advice that I can't wrap my head around is to leave the fan on all the time. I can adjust the speed of the always-on fan, from 35% to 100%. The default is 50%. On the upside, our brick bungalow is much cooler at the same temperature as we used previously. Also, the upstairs is much cooler. On the downside, is my electric bill going to skyrocket? Also, my previous”

“The air cycler in my attic is making this noise when it kicks on. It'll stay on for 3 to 5 seconds then turn right back off. Cold air does come through the vents when it's running but immediately kicks right back off. I got up in the attic and took this video sorry for the loud breathing. Can anyone help diagnose? submitted by /u/ZookeepergameDear296 [link] [comments]”

“Fan connected to contacter instead of capacitor is this normal or am I wrong is this wired up correctly fan turns on only when the thermostat sends signal submitted by /u/Joseb1987 [link] [comments]”

“Don't know what to do or believe. Our house is 6 years old, one story, 2600 sf. No major A/C issues till this year. We were told to unplug the fresh air damper when outside temps were getting above 75. We've been battling high indoor humidity constantly between 60-75%. Been running a portable dehumidifier and emptying 4-5 gallons a day. So decided to plug the damper back in. Ten minutes later the blower stopped and the compressor kept running. No breakers tripped. Turned off the whole un”

“Hello I had an ac repairman come out and he told me he turned up the fans on my ac unit. Now my partner and I are experiencing increased allergies. Do you think that's a coincidence? submitted by /u/InterestOk526 [link] [comments]”

“New homeowner that has never had central air before - is it cheaper to keep the central air “on” all the time and set the thermostat to a higher temp when not home, or to turn on and off constantly? submitted by /u/Gloomy-Intention7079 [link] [comments]”

“It will turn on and off a couple times an hour only in the summer when I run the AC. I have no idea what it is. (Please excuse how dirty it is in the area!) submitted by /u/jenergee7 [link] [comments]”

“I moved some stuff up to my attic today and noticed the fan was making a noise, it's like a click, then an electrical hum, and another click. The fan usually turns on automatically when it's super hot. What is the noise, is something wrong with the fan? submitted by /u/notyourghostie [link] [comments]”

“Freezing basement and hot upstair, so I want to try running the fan with no AC, but when I turn the fan to “On” I hear the AC condenser outside turn on. I set the temperature to a really high number and the ac still triggers. I also see there’s no Y wire, isn’t that what dictates the compressor to turn on? I just bought this house and this didn’t come up in inspection thanks all submitted by /u/International-Seat99 [link] [comments]”

“I have this fan in my skylight of my apartment. There are no other windows besides this and I feel like if I could turn it on it would blow hot air out. But I’m not sure so I came here to ask. It gets up to 90 in my living room and humid. Wish I could use it! I’m just looking to see if anyone knows what I should do or what it’s called submitted by /u/honeyviolennce [link] [comments]”

“I have a kitchen exhaust fan that is tied into the ansul system. It works great as long as the switch is in the up position, and during testing it continues to run and kills the make up air fan which is correct. From what I can tell is I need a parallel path around the switch. So it will run even if the switch is in the off position. That makes sense. But I am lost as to how to wire that. I found this schematic online. Does it make sense to anyone? Can anyone break it down to me? submitted”

“I had one of my HVAC systems replaced last summer. They had to replace the entire system with the main unit in the attic and the compressor (4T variable speed American Standard). I didn't think twice about it: it is out of sight out of mind. I have a maintenance contract with the installation company. Recently the drip pan overflowed from condensate line occlusion. The drip pan filled up with water and wasn't secured properly and sagged down so the shut off valve never activated. Of cour”

“How can I fix this noise and (seemingly) imbalance? submitted by /u/Action_Hairy [link] [comments]”

“I have an intermittent rattling noise coming from the indoor air handler for quite some time now. It only occurs right at startup when the system kicks on, lasts for a few seconds, and doesn't happen on every single cycle. Once it's running continuously, it operates quietly. submitted by /u/Succuteland [link] [comments]”

“The outside fan doesn't come on every time. Seems to have more trouble in the middle of the night either because it has been sitting or because its cool idk? So I've looked on YouTube but those videos show fans having the blades under the motor. Mine has motor under blades and just looking didn't see oil ports. So should I try to oil the shaft or is that going to cause issues since the oil might run in to something? submitted by /u/light_chaser1 [link] [comments]”

“Hello everyone I was seeing if anyone had a thought on what this noise is it’s on when the fan is on and I don’t know anything about these things. submitted by /u/Dinoeater117 [link] [comments]”

“This sound is coming from near HVAC equipment, there is also a tankless water heater up there. It rarely runs for more than a minute then powers down, then cycles up again. The length of each cycle varies from a few seconds to a minute or so. Turning off the HVAC breaker doesn't stop it. Using water or not doesn't seem to influence it. Is this a condensate pump and is this normal? It seems to happen more often in the very early morning, but happens various parts of the day. I don't r”

“So basically if the upstairs ac turns on it will run both upstairs and downstairs, even though the downstairs thermostat has everything set to off (no fan, not auto, just off) Had an ac guy come out a few months ago and he did quite a lot of work. He fixed a leak in our refrigerant, replaced the motor of the fan, and replaced the motors of the dampers. However we have the issue of the ac running downstairs even if the temperature is below the set temperature. I went upstairs and noticed the damp”

“I live in a two story condo with central ac and heating system in the roof. I live on the second store and my neighbor below me. Whenever my neighbor uses their ac, strange clicking noise comes from ducts every 5 seconds. It's only when his unit is on. What could it be and how can I diagnose it. I have attached a video of the noise. submitted by /u/According-West8842 [link] [comments]”

“I’m experiencing an issue with multiple AC repairman coming out… they’ve changed the condenser fan now, and it’s still doing the exact same thing. He came back and put a wood barrier to block my other air conditioner from blowing hot air into this one and the same results. It seems some kind of internal temperature sensor is being tripped in the fan and it turns itself off repeatedly. As soon as it cools down outside, it functions perfectly fine. Most of my problems are from about 11 AM to 9 PM.”

“Hi, so i have a very old Tempstar outdoor AC unit. I was sure the fan was busted despite it spinning smoothly by hand. Difficult to start up and it sometimes makes weird sounds. Finally doesnt spin at all despite getting a new capacitor. Got a new generic motor unit and switched it up. Looked at all the wiring diagrams and it seems new unit by default goes CCWLE while I need CWLE for the fan blade setup. Switched the two connectors that determine rotation on the motor, from Blue-B Yellow-Y to BY”

“Hi everyone, I just moved into a new apartment and the AC is making horrible noises when the fan runs. It only happens on occasion but it is directly over my bed and wakes me up. Does anyone know what the sound is and if it is an easy fix? I rent from an independent landlord so it wouldn’t be as easy to get a tech out here. submitted by /u/Present-Piano-9820 [link] [comments]”

“Warm summer out there. I have a small question to ask. Which method of or dictates your air handler setup. Presently I have, what I term a forced draft system, fan below the evaporator coil. I have 4 return ducts requiring filters. Sold a home with what I term an induced draft air handler, fan above the evaporator coil with a single filter below the evaporator coil. So, what dictates the orientation.? Quite happy with my present system, but was confused at first about drain and the air from it.”

“I was reading in another post here about somebody AC not keeping the house cool. I saw a lot of people saying to keep the fan on instead of “auto”. Will that wear out the fan much faster? Does it help the AC as a whole work less hard to cool things down all day? My outside unit is pretty new but the fan unit in the attic was ok (and more money than we could afford) so we didn’t replace it and I’m worried about having to replace it sooner than necessary. I have almost zero knowledge about HVAC so”

“Today a loud squeaking noise started in the furnace closet and now our AC is struggling to keep the house cool. My husband and roommate tried to figure out what’s causing it but couldn’t. They replaced the filter just in case. The fan is spinning in the unit outside and I can hear the air running inside but the temp keeps creeping up. We have it set to 72° yet it’s 76° now. Also we replaced the capacitor a couple months ago and that fixed our issue then, but the problem back then was that the fa”

“We had this AC installed less than six months ago, and we’ve noticed that it makes a strange noise when it shuts off. It’s cooling the house just fine, but we’re wondering if this is something we should be concerned about. submitted by /u/Dependent-Flower2058 [link] [comments]”

“I expect the answer to be dumb idea, but I'm inquiring because I've got 8 bags of fiberglass batts just sitting around because the desert area I live in has had an extreme run of heat — like, we're lucky if the outside temp gets down to 90F at midnight. I'd like to install them sooner rather than later because our electric bills are obscene (last one was around $380 I think, and this is not an otherwise high-COL area). I would just do it really late or really early but even then”