r/hvacadvice

This furnace was installed at the end of winter last year right after the blizzard ( during which our Old Furnace had failed, because of course) he came back to install the AC on top of it this spring and for some reason when I turned on the heat for the first time this season (last week) I felt like I needed to go down and poke around (kind of trying to figure out which, heat or aux, setting on my thermostat controlled the furnace in which controlled the heat pump) and I found the exhaust kind of what I felt like was disconnected. Am I wrong? Should this not be sealed with purple at the top and reach all the way down into the built-in exhaust port thing? I'm a homeowner with nearly no knowledge about this stuff.

(we've already decided to get a new HVAC guy/ company after this install. We really had wanted him to fix our old one not to buy a new one but it was a unit from 1999 and both it and the AC coil have been repaired multiple times)

Eta: there is enough pipe so that it can be inserted both into the exhaust Outlet on the furnace and the upper elbow but only just. And then still it's not sealed with any PVC cement. I have some PVC cement and I could connect it at the elbow. Should i?

I know the smoke came out, that bit was obvious but why? :-)

Got my 608 cert, spent about $1000 for the tools I didn’t already have, and my wife and I installed a 9k MUZ/MYZ-GX09NL for our log cabin home office.

Followed the Mitsubishi manual exactly including:
- vacuumed down to 200 microns, making sure it stayed under 350 for an hour.
- pressure tested with nitrogen at 600 psi for 24 hours.

Still need to run a stability arm to the cabin, will do that in the next couple days when we get the vibration isolation part I still need. Practiced flaring on extra lineset for a while before doing it for real. Used nylog on all connection points. Electrician comes in a couple days to add a sub panel and cut off switch to the cabin and wire it in.

Took 2 8 hour days for us, and most of that was making sure we understood every step before attempting, and learning/practicing with the tools we hadn’t used before. I think that time would be cut in half for another install for a simple single head unit.

Thought I’d share my experience if there are others considering a similar path.

I starting hearing this noise inside my basement about couple days ago but didn’t realize it came from the outdoor unit until tonight. Cooling still works inside the house and the unit is keeping the temp down. Thanks.

I’m trying to replace my old thermostat, but I don’t know if I’m able to do a smart thermostat or not. I had the two cables attached to the back of the panel and then there’s two more wires. If anyone can help would be greatly appreciated.

I know nothing about HVAC beyond lurking in the sub and was looking at a new construction my friend paid for and noticed this bundle of spliced wires is on the top of the HVAC system. Does this seem correct and or up to AZ building code?

Just wanted to share my first mini-split install to see what you guys think.
Put this 24k Gree Sapphire on my detached garage in New England for an upcoming ~1,000 sq ft in-law suite upstairs. After a full winter, it’s been an absolute beast.

Anchored a DiversiTech offset bracket straight into the poured foundation to keep vibration off the house and clear the snow line. Had an electrician fish a dedicated 240V circuit across the garage, then I wired up the disconnect and added a AG3000 surge protector, ran liquid-tight whip, and pulled 14/4 shielded tray cable with heat shrink on the outdoor terminals for the comm line as well as added the hepd80 surge protector at the panel as well since I had it laying around.

Bending that 5/8" suction line without kinking was a fight as I’m still learning and my POS ratcheting bender wouldn’t do it, but eventually I got it swept cleanly after heating it up just slightly. I cut the factory flares off, re-flared with my Navac, used a bit of Nylog, and torqued the flares to spec.

I borrowed a small nitrogen bottle to pressure test with then pulled down a good vacuum with a harbor frieght pump and a Appion mega flow hose and then felt I was good to crack the valves open. It’s been running well and has held the space through low temps with zero backup heat, and on our 16¢/kWh municipal electric, it barely touches the bill.

Im still learning so I did this first install on my own home and hoping to get better in the trades. Feel free to drop a comment on what you like and didn’t like that could be done better.

I’ve told my landlord about it and they’ve been useless but while I work on dealing with them I’m hoping to see if I can DIY. In addition to the inconsistent temperatures, there seems to be some condensation from some of the pipes around the unit. Google searches are suggesting the drain pipe needs to be cleaned but I don’t even know where to start with that on my system. This is probably a long shot until I get my landlord to have a technician come out, but does anyone have advice?

My AC tech changed the contactor and now started making this noise. Is it bad? What could I do?

My A/C stopped working and got two different techs to look it both say there is no refrigerant left in the system so some kind of leak.

The two quotes are $250/lb and $189/lb for 410-a refrigerant which I can find on the internet for around $20/lb

I'm in California if that makes a difference.

EDIT: I'm not stupid and know that the leak needs to be found and fixed as well. They both quoted for leak test and repair ($900 and $480 respectively). My question is 1000% markup on refrigerant normal or is some kind of shenanigans going on with the websites I found.

I’m trying to identify what sort of mortar or sealant is used currently when replacing a furnace exhaust pipe into a flue. I know this isn’t code but I’m not a plumber or HVAC guy so IDK what’s currently being used instead of the set up at my house. I’m hesitant to use any sort of mortar or cement (assuming I have to bust it out). I’m hoping I can slide the pipe out and use 3m fire sealant. Any ideas? Thanks!

just had a company come in and install a brand new 2/3 Ton Gree heat pump along with installing a gas line so I now have a dual fuel system.

I was looking closer at the heat pump and it looks bent on top and like they dropped or damaged it while installing. what do you guys think? should I bring it up and try to negotiate a lower price before I pay them?

Must have been done on purpose, but I am questioning the logic. They are coming back this week to attach the heads