HVAC Systems Failing & Malfunctioning

“I had my basement flood a few months back. I left my system off until now. Ive been using window units for ac. But its about to get cold. So I tried to see if it would work. Outside unit runs but nothing from the inside unit Works. The thermostat works and the condesate pump will run. I bypassed the condesate kill switch to make sure thats not the problem. I tested the transformer with a multimeter and its showing ok. The 5 amp fuse is also ok. I also tried it on emergency heat and the furnace i”

“My hot water tank was changed and I think they told me to turn the wrong red knobs to turn the heat on because cool air is coming out still can anyone help me please? The last photo is my old tank submitted by /u/Born-Worldliness-180 [link] [comments]”

“Hi, I’ve just moved into a house and noticed the boiler doesn’t have a magnetic system filter, I want to add one but am unsure what route is best, do I go for something like picture 1…or 2 and chase some of the wall out to bring the return pipe through the wall to add the filter on? I obviously want it to be as neat and tidy/shortest route as possible but these newer builds don’t leave any room to work on the pipework! Thank you in advance for any help! submitted by /u/CarefulJellyfi”

“I moved into this mobile home rental about two weeks ago. When I had asked about furnace filter changing, the woman stated when it was installed they said it didn’t need that. Right now it’s roughly 84 degrees in here and it’s blowing hot air out of the vents. I can’t help but think there is actually a filter in here that needs changed but I cannot find out how to get to it!! submitted by /u/FairMany9490 [link] [comments]”

“If I replace my furnace will the new one have a new filter, or is the furnace filter always the same and the rest of the machine is replaced? submitted by /u/Buff__Wizard [link] [comments]”

“I have a 30 year-old York diamond 80 furnace in my basement. I noticed water getting in the paper filter compartment and running the filters. I was figuring most likely a blocked Condensation line was the issue after looking at it with a friend. Because of the total home Warranty, I opted to reach out to an HVAC technician through them to look at it. Home Warranty company has not sent me the report that was written by the technician despite my request to see a copy. My sister was there at the ti”

“In 2021, I replaced the oil furnace in my house with a high-efficiency natural gas furnace. I ran that with my existing AC system until summer 2025 when my AC finally kicked the bucket - it was leaking R-22 and my HVAC company was no longer allowing their techs to touch this refrigerant. So last year I had a Daikin DH5SE heat pump installed. It ran flawlessly for 11 months, and ever since July this year it's been having trouble keeping up. It'll run for 3, 5, 8, sometimes 11 hours straig”

“My wife and I just bought a house with a propane forced hot water system. It's 70 today where I live and I came home to find the boiler running, though the thermostats were both showing it was nearly 70 in the house and were set to close to 50. I went to look at the relay (not knowing what it means at all) and noticed these lights flickering. I know I can turn the boiler off for now but I'm curious for some info about what's going on. Thanks in advance! submitted by /u/v_”

“Hey all, I consider myself pretty handy but this one’s out of my league. I have an older oil-fired hydronic boiler that’s otherwise running well and producing heat. One of the circulators has stopped working, while the other older circulators are still working normally. The failed pump still hums and can feel vibration to the touch, but never gets hot. The failed pump is a Grundfos UPS15-58RC (red pump in photos). Is there any steps I can take myself to try to get it working again or is it toast”

“I had a tech look at my AC and they said it showed signs of a grounded compressor with 309 amps going to the compressor at start. I am just wondering if it makes sense to replace the furnace with the ac unit at the same time or just the condenser and evaporator coil. The house was built in 2019. Edit: This tripped the 60amp at the house and 200amp at the main. When I said signs of being grounded, I was just copying the words in the report. I have had issues last year where a hard start kit was a”

“I'm helping out my dad, and went to replace the furnace filter. It's an Olsen BCL 120S. Forced hot air oil burner. It had a 16x25x1 filter in it, but that looked really wrong. Looked up the manual and it says it's supposed to have a 20x25x1. (Great.....) What MERV should I get? Seems my options locally are MERV 5 and MERV 11 at the local Lowe's, or drove a bit further for a MERV 8. I'd ask the company that does the service, but they are the one that put the wrong filter in, s”

“Hello , I am having some trouble comprehending that i need to replace the heat exchanger 3 years Into a new installed furnace. Admittedly I hav replaced the filter only 3-4 months intervals see pictures of filter before and after. See also pictures of ductwork. Will the limit in airflow cause this ? With this info ? Any advice is appreciated. The ductes were cleaned 2 years prior, I just hired someone to do it. Any advice at least on how to avoid this / is this normal would be appreciated. The f”

“New homeowner. We have a forced hot water heating system that uses heating #2 heating oil. My wife changed the thermostat in the living room and now the heat won't work for that room. I thought it might be a fuse because she didnt shut off the electricity before doing the work and she said the 2 wires touched and there was a small spark.... but We have 2 other thermostats in the house, one for the kitchen and one for the upstairs, and those thermostats still work and trigger the heat to turn”

“Okay hive mind... I had a hot water tank that was backdrafting so it was advised that I put in combustion air intake. When it was installed it was placed next to my HVAC air intake filter... I run my HVAC fan to circulate air all the time. Because of where the combustion air intake is attached to the HVAC I think I'm getting consistently cold air pulled into the HVAC around the filter. I noticed a difference in the temperature of the air coming through the ducting.. a backdrafting hot water”

“Yes. You need to replace the thermostat immediately. This is a potentially very dangerous situation. You need to turn the power off to the tank immediately and replace the thermostat. They are usually available at big box stores and are pretty simple to install. Problem is that if they overheat enough the tank will burst or activate the t&p valve expelling hot water. It's a very bad situation. Get it fixed. Pronto. It's fine to turn it on to warm it up for a shower but do not leave i”

Hydronic(hot water)

“Context: I own restaurant a with a house/apartment unit attached above. I live in the house, own/operate the restaurant. The house has indirect-fired hot water with this Munchkin unit, which seemingly heats both the hot water and the house heat. Restaurant has its own traditional gas hot water heater. The house’s indirect tank started leaking, so the water has been shut off. A previous owner had connected the restaurant’s water heater to the house plumbing (which had been a closed value). So aft”

“My home had a steam humidifier for the heat pump / backup oil furnace. It is unrepairable. I may have my values and units wrong, but I think he said it was a 9 kW system. The HVAC company that services the oil furnace gave me a quote of $2,500 for a new 12 kW steam humidifier and $1,300 for water humidifier. Tech said Honeywell doesn’t make a smaller steam unit. He also said he would need to make ductwork modifications for water. What the pros and cons of each? I’m not concerned about the $1,200”

“I just noticed while in my basement that one of the PVC pipes for the furnace broke. No clue how or when it happened. Pretty sure that its the exhaust side, i marked the photos with color to show which is which. Am I safe to run the AC overnight until I can get to the store to buy repair parts tomorrow? No chance the heat runs overnight but if i can lock it out somehow I will do that too. Thermostat is set to cool only. submitted by /u/gcollins30 [link] [comments]”

“Hello, My current Ac unit is from 1992 with r22 refrigerant. Someone came out and diagnosed that is had a leak and due to its age and cost of repair, it would be better to be replaced. My furnace is a lennox pulse also from 1992 and has been running fine. He quoted $5100 for a 2ton lennox merit Ac unit and $6000 for a lennox elite 2 stage furnace. So we have a few options that i would like advice with. Should we replace the Ac unit keep old furnace, replace the ac with a heatpump and and keep th”

“change the mode to heat pump only and see if it starts running the compressor, if not try resetting the breaker for it”

it looks to be a condensate line, is there a ac/furnace near by?

“Please help me settle a discussion with my wife. We have a boiler that provides hot water through a heat exchanger to the house faucets, showers, tubs, etc.. We’ve had issues over the past 6 months were it doesn’t light consistently, meaning no hot water, which we’ve been addressing with the installer (not the point of this post). My wife insists that she can tell when the boiler won’t light because the cold water from the faucet doesn’t get as cold as when it’s working properly. Does this make”

“Yesterday afternoon I noticed the temp in the house wasn't dropping with the a/c on. Air coming out of vents was room temperature, so I go to the basement and there's water all around the bottom of the furnace. Realized it had been a few months since I changed the filter, checked it and it was quite dirty with gobs of pet hair on it. Did some reading online and figured the coils were frozen. I let it thaw overnight, put a new filter in, this morning tried the a/c again and nothing, the o”

ok thank you will do

“I have two AC units in NE Texas in a home built 6 ago. One is a 4 ton, another is a 3.5 ton. Specially, the units are (Installed vertically): - CBA38MV-048 - CBA38MV-042 Background: - So for the first few years, everything was fine. About 4 years in, we noticed that the air filters we were pulling out were partially wet. - In the summer we try and keep the AC set to around 77 or 78 to not overwork things. Its 103 outside today... - So we called service, they cleaned the units but the issue didn&”

“I just got a Carrier heat pump and air handler installed yesterday, and as you can see in the photo, the pipes are blocking access to the air filter. It seems like the pipes should not have been installed this way. Am I missing something? I have not paid yet because there was also a problem with the motherboard on the unit and so they need to send out a senior technician. Thanks in advance. submitted by /u/TTraditionalPast [link] [comments]”

“New homeowner staying ahead of the impending cold weather. Changing the filter on the tank and nozzle today but I’m pretty uneducated on boilers. Before I pay someone to come service this What’s everyone thing of the condition on this thing? It’s a Weil McLain but unsure how old. Thanks submitted by /u/Primary_Attitude_923 [link] [comments]”

“I had my furnace replaced with a Carrier Comfort 80. The existing AC is a 2 ton unit. It is struggling to keep up and the coils are freezing up at the end of the day. I am wondering if they undersized the blower in the new furnace. I also have a shut off switch for the drain line(photo attached) Is this supposed to be locked or unlocked? submitted by /u/Comfortable_Agent429 [link] [comments]”

“My AC will run for a few days, then stop. Once this happens it will turn back on if I turn it off and back on again. I often have to do this every 60-180 minutes for 18-20 times until finally one day it just decides to work for 3-5 full days again, then the cycle repeats. This has been happening for a month now. I’ve been working with a local HVAC company that does my cleaning. They are very nice, and literally have charged my nothing so I know they are just trying to help… but I’m not sure if t”

“Its been real hot here in st louis and the ac hasn't been keeping up and I've notices some water coming out, why is this happening, the drain line isn't clogged. submitted by /u/Sad_Revolution_5756 [link] [comments]”

“I have a electrostatic washable air filter for my furnace and am unsure of how to clean it, how to tell if it's still good and also can't seem to find a disposable replacement with the same actual size. Any help would be appreciated 🙏 submitted by /u/Minement [link] [comments]”

“I just moved in to a new apartment. While I initially thought it is central AC, I grew suspicious after several days. Then I took off a vent located at foot level underneath the thermometer, poke my phone pointing up and took a photo. Image 1 is the result. Image 2 and 3 are the structure of this well, the small vent (marked green) at the bottom is the only entrance that appears to provide access to the AC unit (marked blue). The vent itself measures 23 in x 12 in, or 59cm x 30cm. I am skeptical”

“Moved into apartment a few months ago and was given a replacement air filter, but I have never seen a furnace that looks like this and have no clue where the air filter is located. Google isn’t helping. Anyone able to assist? submitted by /u/dede_rich [link] [comments]”

“I’m in New England and currently have a 20+ year old Lennox 3 ton condenser. I also have a 4 year old Bradford White HE boiler that’s connected to an indirect water heater and hydro air system. My a/c will literally run 6-8 hours straight without shutting down. It was last serviced about two years ago but filter has been replaced a few times. Part of the job is also adding a second zone. I’m excluding that from the figures. House is 25 years old and well insulated Company 1: First Company hydron”

“Hi there, i was hoping to get some quick insight. I live in an apartment and the office changes my furnace filter every 3ish months i believe. I have 5 cats so i change it about every month. In between changing-when the filter eventually gets hairy thats when theres slight bubbling. If I take the filter slightly out and put it back the popping is gone for now, unsure how long it takes to come back. There was a time I took an extended period of changing it, it was crackling real bad-went to chang”

“Hi all, have a quick question about the exhaust pipe on our furnace. Back in January our heating unit (baseboard) completely failed on us and the entire unit had to be replaced aside from the pipes going to each room/level of the house. I’ve noticed and I’m sure they’re not related but I pay way more attention to the new unit than I did the old unit, that when we get heavy rain water leaks into the indoor system from the vent. Can I just replace the “T” vent that is on this with an elbow pointin”

“I have a 10 year old HVAC system (with 10yo ductwork from new construction) including central AC. My spouse has severe health issues so we've always used high quality filters. [I actually used off-brand MERV 13 filters for a number of years before realizing all of them fit so loosely they weren't actually filtering; after getting the 3M Filtrete brand and changing every 3 months they've been fantastic.] I usually use Filtrete MERV 13 MPR 2200, Elite Allergen. The size I need (14x24x1”

“Hello! I’m sure this question has been answered already, but bear with me as I’m a first-time hvac owner and I’m asking for my own peace of mind… did I install the filter correctly? I’ve read different things about how I should place the filter in the direction of the airflow, or towards the equipment, but it’s still so confusing to me. Directions are hard for my old brain. Thank you! submitted by /u/ImmediateAwareness32 [link] [comments]”

“Someone please explain this to me like I’m 5. I just replaced my furnace and AC with a new high efficiency furnace and cold air heat pump (I’m in Winnipeg Canada). Everything was replaced on Wednesday. Since then, my furnace has not stopped running. It’s forceful and way louder than my last furnace. Is that normal? Also the heat pump is HUGE, my house is only 928 sq ft. I also noticed that it’s quite a bit more humid in my home than it used to be (when my traditional ac worked properly). Is that”

“Hello: I have a carrier ac/ furnace system. The current filter is have is: https://www.discountfilters.com/furnace-air-filters/airx-20x25x6sg-health-2-pack/p174374/?alt\_name=20x25x6%2BMERV%2B13%2BReplacement%2BAir%2BFilter%2Bby%2BAIRx%2C%2B2%2Bpk%2B%7C%2BFurnace%2B%26%2BAC%2BFilter%2B%7C%2BPleated%22&\_oid=MAF\_AM\_REP\_20X25X6\_M13\_2%2F%3Futm\_medium%3Dcpc&gad\_source=1&gad\_campaignid=21890657692&gbraid=0AAAAAD9E1b8J-kqcZ5cZ-91yYwE-L-CET&gclid=Cj0KCQjwsMLSBhD9ARIsAIpUTDou”

“We got power switched on today and it’s disgustingly hot in Paris, so naturally, I tested the AC first thing. The good news is that it blows really cold and really strong. The weird news is… in the basement in the sink, water starts GUSHING out of this pipe over one of the sinks. I have no idea what’s going on, but it’s definitely part of the AC. As soon as the cooling mechanism kicks in the water starts gushing, and as soon as the cooling kicks off, the water stops. It’s waaaaaay too much to be”

“Lucky to get hold of the Meaco 14000btu, and it got Delivered yesterday morning. After turning it on hours after delivery, I noticed that the area between the back of the ac and window is really warm. Also the fabric and the window frame itself has become warm. Not sure if that's the reason why the AC is struggling to drop the temp. The room is about 28m². Managed to bring down the temp 5degrees overnight. Any suggestions please. submitted by /u/Glittering-Start-658 [link]”

“Leaning towards the Carrier, but any advice welcome. Also, any advice on what else to ask for or if the quote is reasonable for each of the work/activity listed? Currently have a 29 year old Weather King 4 ton, leaking refrigerant kept having it refilled, but leaks/freezes over. Probably at end of life! Edit to add: located in Massachusetts submitted by /u/Cerealmilk2024 [link] [comments]”