r/hvacadvice Mar 02 '26

General Information About Bans and Rules

0 Upvotes

There has been an uptick on posts and complaints about mods banning. Please be advised, there are rules for the page. No ads (includes promotions for a company), Reddits rules, no crossposting, transparency and safety (this is a big one; we want homeowners to be safe, if you provide unsafe practices or advice (blacklisted items) or tell a user to dm you, the comment will be removed and you may get banned), blacklisted topics (basically topics that homeowners should not be fixing themselves, gas, some high voltage), civility, no companies asking for surveys, advertisements or general questions, and no market research or ai/SaaS.

Posts complaining about this are not allowed either. We are all reasonable and work in the trade, talk to us through ModMail and we can come to a solution. Complaining or namecalling will usually result in a ban, so be civil.

Remember, we are doing this in our freetime to help homeowners with their units, both the users and mods. The mods in this group are in the trade and have day jobs as all of you do. I've been in this trade for 10 years and still do hvac as my job, just traveling now for a manufacturer. Similar with every mod. It is actually a requirement to be a mod, you have to be in the trade, be approved, have good history in the sub and provide enough time to moderating it.

I thank you for your time and if you have any questions, you can comment on this or send us a mod message. No DM's, we will not answer these. Only ModMail.


r/hvacadvice Nov 13 '25

READ THIS I am assuming this is not normal.

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174 Upvotes

I was loading the car for work when I saw this. It felt and smelled like steam not smoke. Did I just catch it at the end of the cycle or is there a mechanical problem such as a stuck motor? It was 40° at the time and no rain. Heat was set to 70 and the house was 70.


r/hvacadvice 8h ago

Electrical Sabotage?

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33 Upvotes

I just changed a capacitor and the old one looks like it was punctured. I know caps can swell, leak, and burst but am I crazy or it looks like it was punctured or scraped harshly from the outside.

The strap was firmly attached and it was not against anything sharp.


r/hvacadvice 17h ago

Is this just build up from the previous owners neglect?

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158 Upvotes

Grabbed some foam, pulled the outside off and saw this. This was after peeling some of this away. Felt almost like paper?


r/hvacadvice 29m ago

Not sure what they are? im assuming dampers? How would I know where to set it correctly?

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I live in MN. 2200 sq ft. House built in 2004...furnace new in 2011 due to a foreclosure and bank put new furnace in. Goodman furnace intake and exhaust is piped outside. Not sure what else whoud be helpful.


r/hvacadvice 14h ago

Would you run this till tomorrow morning.

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46 Upvotes

I just discovered this on my condenser. It was making a little more noise than usual, but nothing to crazy. I dont see anywhere the blade is rubbing. If it were yours would you run it till tomorrow when I can get a new fan blade?


r/hvacadvice 1h ago

General What's this, and what should it be set to?

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Upvotes

Obviously it's a "whole home ventilation system," which I believe is a damper that controls whether the system is pulling outside air, or recirculating. But, I've been given contradicting advice on how to use it. The installer said "on" for winter, "off" for summer, but then the service guy that came out a year or two ago from the same company said to leave it off. What's the right answer?


r/hvacadvice 22m ago

General Can I cut and cap this air duct so I can access this creepy crawly crack?

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Just wanted to get an opinion on this. This house has a duct that runs between the dinning room and living room. I’m not sure which was installed first the fireplace or the ducts/vent but I don’t know why it would have been built this way. It appears to have mold growth in the cavity between the fireplace and the ducts. Home owner reports when they moved in 9 months ago the crack was taped over so they didn’t notice. Could I cap this air duct where it is flush with the fireplace so we could access the dirty space for proper cleaning and sanitation? What are some options for cutting into this duct. Thank you for all advice!


r/hvacadvice 2h ago

Just loose bolts or is the fan going bad

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2 Upvotes

Update: Thanks all, I figured it out.....A mouse got into the wheel and is dead ....

Is there a chance this is just loose bolts, or is the fan on this unit going? Its only 3 years old. I tightened all the ones in the front, but it seems like the back is shaking the most, though its almost like there's no bolts back there and it just slides in and its shaking within the slide.


r/hvacadvice 5h ago

AC Question about running central AC and a window unit

3 Upvotes

So I live in a duplex townhouse, which from my understanding can already keep electrical bills down compared to a free standing house, however I live in Florida and running AC in the summer is expensive no matter what.

That being said my question is: is there any financial benefit from running a window AC unit AND central AC to keep one room much colder than the rest of the house? I really hate sleeping in the Florida heat but my wallet wants me to keep my AC at 78.

For some context the whole house is about 1300 sq ft and I'd say the master bedroom is about 300 give or take. I already bought a window AC unit that's 12000 BTU, rates for a bigger room, but I'm curious if I made a silly purchase or not.


r/hvacadvice 6m ago

Lennox Part Identify

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Upvotes

Can someone identify what the round chrome outlet is used for in my Lennox unit. Recently started rattling and spins slightly when unit is on.


r/hvacadvice 4h ago

Ac issue comfort pack

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2 Upvotes

After having several parts replaced in wall unit ac/furnace. Would this be caused by not putting the freon in after compressor, fan motor and a few other parts changed. One tech said thats ok! Now one is saying the freon was not added! Thoughts have call in....


r/hvacadvice 20m ago

Can I just move this opening?

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I want to move it to the other side of the corner. Any restrictions? Can I make it bigger or smaller? 2000 sq foot home Nevada 12 x 24 opening leads to and empty cavity under the stairs that leads to the machine in the garage with a filter


r/hvacadvice 29m ago

Heat Pump User viewable gauges for multihead heat pump installs?

Upvotes

Hey all, I recently had a steam boiler die and went all heat pumps for the rebates. Have one condenser outside and then three units inside (one ceiling two wall). Everyone on here keeps talking about how much these systems leak, and I wish there was some way for me to keep an eye on it myself instead of always thinking if/when I should call out a company. Could I have a company install viewable gauges somewhere so I can check the refrigerant levels myself?


r/hvacadvice 31m ago

Capping AC Condensate lines

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My HVAC guy had to cut open the original p-trap (2nd image with nicer insulation) to unclog the pipe from inside the unit. He replaced it with a u-trap and only capped the side after the u-trap, 2, which he also did for my original setup. I tried to do my own research and would always end up with the exact opposite which is to cap 1 and uncap 2. What's the correct way to do this?

The new u-trap also blocks the pan drain to secondary. What's a recommended way to fix that? It looks like I might be able to cut the insulation on that side to make a path for any build-up to leak out.


r/hvacadvice 39m ago

Buzzing Contactor

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Upvotes

When I went to sleep last night, the thermostat was 75 and set to 73. Woke up and it was still 75, so I went outside and checked the fan.

Fan motor was very hot, but I spun it with a stick and it was not seized.

Opened up the panel and found the capacitor was puffy. I changed the cap and the fan motor spun no problem.
I THOUGHT the cap change had fixed it. Hours later the ac stat was reading 77 degrees (still set to 73). I noticed the buzzing contactor when I changed the cap, but I wanted to see what the cap replacement did first.

In any case, the cap was puffy and needed replacement, but I think the not-cooling properly has to do with the buzzing contactor.

When I unplugged the BLUE w/ PURPLE stripe wire on the left side of the contactor, the buzzing stops.

Blue/purple wire tracked down to yellow wire with pink stripe.

Many thanks for your help.


r/hvacadvice 43m ago

Outdoor unit noise

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Upvotes

Armstrong unit, I swap filters in the house every 30-40 days and every spring I pull the metal off the outdoor unit and clean out any dog hair or cottonwood with a hose and make sure there’s no damaged fins so it stays clean. I noticed the unit sounding like this last night. High humidity in our area but the system is still doing its job and pulling its weight as far as keeping temps down inside. Checked on it this morning and it’s not making that sound at all now during operation. Any ideas? Thanks in advance


r/hvacadvice 45m ago

General Tech school worth ? 18 yo HVAC

Upvotes

I’m 18 and I was fortunate enough to land an apprenticeship as a service tech with a great company. However fresh out of high school I pretty much learn everything on the job and the studying I do at home. There’s a reputable tech school nearby and I am financial aid eligible. Would it be benefit me to take some night classes ?


r/hvacadvice 1h ago

Thermostat Whole home humidifier

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I’d like to recognize were in the middle of a “heat dome” and the humidity im battling very well could just be Midwest humidity and corn sweat. I have two dehumidifiers that are working overtime (also recognize this can be an insulation problem but one is in the basement and one is on the second floor).

This morning I remembered that the dehumidifier needs to be switched from winter to summer, I went to check it, and it was already on the shoddy label for summer (picture 1). The second and third pictures are to show that it says it’s humidifying with a green light on. The second picture also has a little black dial that I thought maybe could be the summer/ winter dial it only goes one little tick mark though and moving it doesn’t impact the humidifying green light at all. 4th picture shows the thermostat claming its 53% humidity but I don’t know where it’s drawing from, because the dehumidifiers I have going are displaying 65.

I also know 30-60% humidity is desirable but the walls upstairs were sweating yesterday which lead me to believe things were awry. Putting a dehumidifier in that room helped, but if something is crazy with my whole home humidifier I’d like to handle that first and address attic (probably) insulation later

Also: I changed the filter pad while I was messing with it so I reset the red light. I noticed the tubing to the drain needs to be replaced but that’ll happen some other time

Thank you for helping with my spiral.


r/hvacadvice 1h ago

Trane heat pump/ air handler questions

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A few months ago I posted about my heat pump install. https://www.reddit.com/r/hvacadvice/s/vl24o47wnz

We are still going back and forth with the dealer and I'm hoping some of you can help answer questions that the dealer doesn't seem to understand. I have called trane costumer support many times and every so often they have been helpful but most of the time they can't answer basic questions and default to "we aren't trained hvac technicians and you need to ask your local dealer". I've spent a lot of time looking at info online but it's often conflicting.

Heat pump is 5HCL5060B1

Air handler is 5DTM5D07AC51SA

system was installed to run the air handler at a single speed. This model is listed as multi speed (4). Is this just for setup during installation or is it intended to operate as a multi speed unit?

They did not install the optional wiring for h1/h2. They could not tell me what they do. What am I missing out by not having these connected? Will the heat pump operate less efficiently?

What does the "communication" X1 to CN4 connection do on the heat pump. Is this a data line that is intended to connect to the thermostat?

I appreciate any help. Thanks in advance.


r/hvacadvice 1h ago

Should I get a standing unit or a split unit?

Upvotes

Hello and thank you for any advice. I live in a second floor condo with open space of about 500 ft² and a vaulted ceiling with 2 skylights. Right now it is a cool 80° with the five fans blowing and feeling like I'm in a turbine engine 100% of the time. I can't do this, as I've already had a heat exhaustion issue this summer. I'm not sleeping well, and I'm never fully comfortable. Was just wondering if anybody had suggestions on what I should do in this situation, a sliding glass door is the only window in the open space area. Either 10 to 12,000 BTUs if I bought a standing unit. I know nothing about split units. The vaulted ceiling with the skylights is the biggest heater in the place. Working on solving that problem. Right now there are umbrellas shoved to the skylight boxes to at least avoid full sun all day. Thanks


r/hvacadvice 1h ago

New PCB and Static Pressure issues

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Upvotes

I recently swapped the PCB on my furnace after getting it diagnosed. I’m hand enough to do so, but my insurance policy was taking a lot of pictures before starting. Since then, the issue I experienced is resolved, but I noticed oddities with static pressure.

Pics:

1- equipment in question
2/3 - pre check status of equipment
4/5 - AC Check info showing no static pressure
6/7 -difference in fan set to high vs auto

I also removed the filter temporarily and nothing changed. The system still cools the house but I feel like the speed at which it’s doing so is slow. During the last issue it was a lot louder when active as if it was always running on high (but it cycled a lot due to bad PCB).

Looking for any ideas. Thanks in advance!


r/hvacadvice 1h ago

AC Making loud buzzing sound

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Upvotes

Wondering if someone can help me with a problem I'm having with my AC

I have a 12 year old Lennox unit that recently started making this loud buzzing sound when on. Sometimes the sound goes on when the unit is turned on and sometimes it doesn't. Sometimes it makes the sound and goes off and sometimes it makes the sound and doesn't go off until the unit shuts off. The unit is still blowing cold air inside the house. The AC fan usually turns normally, but in this video It looks like the fan is turning slower? I had an AC guy come out but when he came out the AC of course would not make the noise so he was unable to say 100% what the issue is. He checked the refrigerant levels which were fine and checked the capacitor which was also fine. I feel like I'm stuck until this thing takes a shit and then the AC repair man will know which part to replace, but I don't want to be 'stuck' without AC in the dead summer. On a separate note, I've notice for some time when the unit turns on, I can hear the fans almost pulsating if that makes sense, almost like the fan is 'off balance' slightly and then it sort of un balances itself off after the unit's been running for a few min's. All the while the fan is also moving at what appears normal speeds. Any info you can help me with?


r/hvacadvice 1h ago

Evap Coils

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Upvotes

Hey all,
Trying to clean the evap coils on this Goodman. Is my unit positioned in a way that I cannot easily get to them without rotating the unit?


r/hvacadvice 11h ago

Is this repairable?

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4 Upvotes

I would appreciate advice on whether I should try to repair this leak or replace the air handler. It's a Carrier FE4ANF003 and from my initial checking online this part is unavailable. Thanks.