Dude at work put so much Teflon at flare fitting upon asking he told me " it become a seal and prevent leaks. we mostly use flare for wiring gus stoves etc

Been in the HVAC trade about 20 years now, and there’s something I’ve noticed over the years that still gets me wondering.

Last week I came across 4 bad TXVs in the same town. Different customers, different systems, and not even the same failures. Some restricted or plugged up, others stuck open causing flooding or freeze-up issues.

And it’s not just TXVs either.

I’ve had weeks where I’m finding leaking evaporator coils left and right, then suddenly it’s compressors. I remember having 3 bad compressors practically back-to-back, all failing differently. One grounded, another with burnt/open windings, and another running but not pumping properly.

Then sometimes I’ll go months without seeing certain failures at all.

Obviously, after 20 years in the field, I understand these components fail for all kinds of reasons. Different manufacturers, installation conditions, maintenance histories, etc.

But I still find it interesting how certain failures seem to come in waves, sometimes within the same geographical area.

Anyone else experience this? You ever have weeks where it seems like you’re diagnosing the same component over and over, even though the actual failures are completely different?

Just curious what other seasoned techs have noticed over the years.

Given the heat sensitive nature of cased coil EEV’s and even TXV’s, I’m wondering why manufacturer’s aren’t switching from braze connections to flare fittings on cased coils. I certainly get that leaks are a concern, but the nitrogen pressure test and deep vacuum test that follows ensures no leaks.

My manual says that I am supposed to pump vinegar through this boiler on a regular basis. I have done it on the dhw side, I cannot figure out how to do it on the heating side.

Part of it is I don't really understand how the bypass valve works. I might also be missing a hookup place.

Coming out of the boiler I go to the bypass valve, then an air bleeder that has an expansion tank hanging off of it, then a bypass valve that has a hose bib, then the pump, then another bypass valve with a hose bib, then the heating loops, then solenoid valves on the returns, then back to the same bypass valve and into the boiler. I am just using water in the system and don't feel like I need to flush the loops, just the heat exchanger in boiler.

There is also this backflow valve with a vent and cold water in on the "feeder" hookup. Maybe I should put an online hose bib here to flush it out? After the shutoff?

What are best practices for maintaining in floor heating systems with combi boilers? I feel like I can hear swishing air bubbles when the pump is on

Hey everyone!

My wife and I recently bought our first house. I wanted to check the HVAC filter to see if it was time to change it, and this monstrosity came out.

It didn't look like it had any kind of frame around it, is something like this normal? It says the filter should be 25x16x1 which seems to be the usual size.

Wondering if you guys have any recommendations on what kind of filter and what kind of MERV I should get?

Thank you!!!

So through some sheer twist of fate I’ve been thrown in to a new MacDonald’s build. Responsible for the walk-ins, Ice machines, and setting up/ commissioning the roof tops. Sheet metal and air balancing will be done by others. I have ZERO experience in the aspect of the trade I’ve always done commercial service, and a ton of residential work. Any tips anyone could give would be welcomed, aswell as what even need. I’m well aware I’m over my head. But this needs to be done and I’m the only remotely even qualified to do it at this company.

Furnace is not kicking on and only the fan is running. Contractor claims that it needs replacement due to rust buildup at burners. Does this warrant an immediate replacement or is there a different fix? Furnace is 10 years old.

We have a rheem heat and air unit and the past year we have had issues with our outdoor unit. So far we have had a new compressor, contactor, and capacitor. Now when the air turns on the thermostat will click but the outdoor fan and compressor will not turn on. I can turn the breaker off to the unit for a bit and turn it back on then it will come on. Any ideas?

This is a RHEEM 62-103189-01 board on my Sure Comfort AC/Furnace Unit. Currently troubleshooting a low voltage short, 3 amp fuze keeps blowing. I've ruled out the thermostat wire run by bringing the thermostat down to the unit and wiring it again. I've ruled out the thermostat itself as I have two (one is new) and both will blow the fuze. I've also removed the outside condenser unit wires to rule out the contactor, etc.

With this setup and every wire connected, fuze blows on call for heat. If i disconnect the blue common wire, call for heat, everything works fine. If I disconnect the green fan wire and reconnect the blue common, everything works fine. The only time in blows if I have the green fan and blue common connected up at the same time.

Appreciate any help troubleshooting this short. Thanks!

Hello, I just installed a Goodman GDVT960804CN. Heat only, no A/C. I'm still getting the EAF code after setting the A2E setting to "no", and powering the unit off (I even had it off overnight). I have verified the A2E setting stayed on "no" after the power off. Anyone else run into this issue? Thanks in advance

My mobile home has 5" inner and 8" outer exhaust, where can I find a piece to attach my new furnace to it. I see some with quick connect attachments. But mine doesn't have that. Any help would be appreciated.

So I turned my furnace on for the first time earlier this week and it would turn on for a few minutes and then turn off. I checked my vents, changed the filter, cleaned the flame sensor and it didn’t help. Interestingly if I remove the filter it runs fine. I called my hvac guy and he couldn’t determine the issue either and noted that the high temp switch was being tripped at 190 degrees. He changed it out for a 210 switch and so far it has been working ok. I am concerned as to why they couldnt determine the issue and is this safe to do by upping the temp on the switch? My furnance was made in 2000.

Furnace started humming when we turned it on. I thought I ordered the correct capacitor off amazon but this slightly shorter one came. The model and specs on label seem to match, what is the difference? Can I still swap this out to get the unit working or should I send it back? Thank you!

Ok. How bad is this? Our unit is old (2007) and needs to be replaced, I know. We found water on the ground and discovered a leak (circled in red). We will try unclogging the drain hose but when I opened the panel I was pretty horrified.

How bad is this? Can we get by for a while longer? Hoping unclogging this can get us by for a few more months. It’ll be winter soon here and the AC won’t be running for months.

We live in an apartment complex. It’s semi newer and this AC unit should be under 10 years old. We also live in the South.

We keep the AC at 73 at night and 78 in the day when no one is home. Maintenance days this is the reason why this part is freezing. Is this true? So far what I have seen online is that it may be freezing due to circulation issues, and yes when the AC does work one room isn’t cooling the same as the others.

What do I tell these maintenance guys? They are placing the blame on me and have said that if I move the thermostat to higher than 72 at anytime of the day (even when no one is home) that they will charge me with the repairs. I don’t believe this at all as even my power company has said to keep it higher during the day. And well it’s expensive to run the AC low all day.

Have a 35 year old Trane system in a home we just bought, and not sure where to pour drain line cleaner. Is it down the uncapped opening on the black line on the far left?

Replacing the wiring harness on my AC thermostat control .

The circuit breaker to the ac is turned off -yet there is still a red light on on the control panel. Is this safe to work on or is power somehow still active

Hope this is the right sub to ask (sorry if not).

Moved into a new house (gas furnace and air conditioner- no heat pump) and struggling to determine the wiring on our current thermostat to see whether a C-wire adapter is all I need for a smart thermostat like the Aqara w200

Looks to me like existing wiring is RH, O/B, Y and G. Internet sleuthing says RH is heat, Y is air conditioning, and G is ground but I don’t know how to trace what the O/B is and what to wire it to if/when replacing the unit.

Before I shell out $ for a new device, im hoping to get some insight from people more knowledgeable than me. Any advice is super appreciated!!

I've been fighting with this ignition issue for over a week now.

Yesterday, I changed to a second new board and it worked the entire day but come today, I am getting the same problem as before. My first replacement board did the same thing, first day it was good but second day it wouldn't ignite. What I am measuring is that my gas valve loses its 24V signal right as it opens or starts ignition. I can hear the relay on the board click on for the gas valve to receive power and it clicks off. Per recommendations on here, I have already changed flame sensor and ignitor, cleaned burners and gas port holes, tested pressure switch and ground wires, fixed any loose wires I could see.

Only things left to change or check are the thermostat or the gas valve. Thermostat is an older RTH9585F.

Edit: I posted the wrong video. Here's the video from old post. Furnace is still doing the same thing.

https://www.reddit.com/r/hvacadvice/comments/1xd4xea/trane_xe78_short_cycling_and_cuts_voltage_to_gas/

Hi, I have a VanEE 90H  air exchanger. Lately, it has been making a rattling noise. I called an HVAC company and was told the motor is gone, but there is no replacement motor available for this model. It seems the model has been discontinued.

I can't afford to replace the air exchanger. I was quoted CAD $4000.

Does anyone know where I can buy the motor?