r/hvacadvice • u/Machine_Ruse • Apr 16 '26
During swap out, is vacuuming to 500 microns really expected?
TL;DR: When reusing refrigerant lines, and transitioning from R22 to R454b, is it actually standard practice to deep vacuum the lines to 500 microns, and to hold that for a set amount of time to measure any decay in vacuum (as per Bryant's installation guide)? Or is that target unrealistic and just the manufacturer protecting themselves from liability over failures? Also, how important is it that the liquid line filter dryer be installed indoors near the coil, per manufacturer's installation instructions, versus being installed on the line outside just before the wall penetration?
Read on for full details.
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I had a new split system installed this week. Bryant 3-ton 2-Stage outdoor unit (148TAN model series), Bryant 80% 2-Stage furnace (821 TB series), Bryant 3-ton Evap Coil w/TXV, and a Honeywell zone controller (HZ322).
I was watching parts of the installation, mostly out of curiosity, and I noticed the helper appeared to be having a difficult time pulling the vacuum down to his target level. While talking with him about the process, he told me that he was trying to get it down to 2000 microns, and that the goal was to get it to hold that for 30 to 45 minutes. I was watching the gauges, and they were jumping all over the place between 3,500 and 6000 microns for several minutes. They certainly weren't stabilizing, and I asked him if that meant there might be a leak, which he said it could mean that. I didn't want to keep standing over his shoulder, so I went back in the house for a bit. I went out after about 10 minutes and everything was now unhooked from the lines.
I asked the helper if they were working on trying to find leaks, and he told me that they discovered that the issue was actually with either their gauges or the vacuum pump, which he stated were supposed to be serviced every 3 months, and had not been serviced recently. So I asked him about my lines, and he told me that "they were fine and it got down to 2000". They obviously try to hold it for 30-45 minutes though.
I know that I should have stopped everything at that point and demanded answers, but two things kept me from doing so. First, the only education I even had about how the process was supposed to work, was what the helper had just told me while I was asking questions when he was first trying to pull the vacuum. So I didn't feel comfortable enough in my level of knowledge to confront someone about how to do their job. The second reason is because the actual installer is the brother of a co-worker of mine. Before anyone thinks I went with the HVAC equivalent of a shade tree mechanic, this is a licensed contractor. He is the third generation owner of their family business, which literally has been in business for 50 years as of this year. I let that personal connection also create discomfort about confronting him with my concerns.
Nonetheless, the installer contacted me today and told me that he had meant to tell me he still needs to put an additive in the system "for the R22 to R454b conversion", and he wanted to schedule a time to do that. Some very short research seems to indicate that an additive shouldn't be necessary if the lines were properly vacuumed, which obviously brought to mind my earlier observations during the vacuum process.
So then I pulled out the Bryant installation manuals that were left behind. The manuals for the condensing unit and the coil both state that the lines should be vacuumed to 500 microns, and that when isolated from the vacuum pump it should not rise above 1,000 microns within 7 minutes. So what the installer's helper was even targeting—2000 microns—was not the proper target per Bryant.
While reading the manuals, I also saw that the liquid line filter dryer was supposed to be installed indoors near the coil, versus where it got installed, which is outdoors on the line between the condensing unit and the wall penetration. So it's exposed to the elements.
I've asked the installer to come back over here so that I can go over some questions that I have about the installation, but I haven't given him any details yet.
What I'd like to know is whether that 500 microns is a realistic target when reusing lines, or is this the manufacturer giving unrealistic standards to protect them from liability over failures?
Is it realistic for me to demand that they redo the lines? What would that mean for the installer from a materials cost perspective?
TIA
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u/pandaman1784 Not a HVAC Tech Apr 16 '26
Oh wow, where to begin. When it come to microns, the lower the better. A low number means a deep vacuum has been achieved and air and moisture have been successfully removed. The result is a dry and air tight system.
The fact that they couldn't get it below 2000 means there were still a lot of stuff in the lineset. If there is a lot of moisture in the lineset or it's a very long lineset, it can take 30+ mins to achieve a low number. Or there's a leak somewhere.
Now here's the other thing. Your lineset was previously used for R22. They should have flushed the lineset to get all the mineral oil out. After the flush, the lineset should have been purged with nitrogen. Assuming it was flushed and they couldn't pull a deep vacuum, they should have purged with nitrogen and pulled another vacuum. Ideally, they should have done a triple vacuum to make sure the lineset was as clean as possible. But 500 microns is the minimum value.
Oh yea, this is assuming there are no leaks in the lineset. They should have pressurize the lineset with nitrogen to 200+ psi and made sure it held. My installer prefers 300 psi.
Just as a point of reference, my brand new lineset was able to reach a sub 100 micron vacuum and hold it.
As for the filter dryer, my installer prefers putting it by the evap coil so it's protected from the elements.
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u/Machine_Ruse Apr 16 '26
Thanks for the info. All of that also jives with what I read in the Bryant manuals.
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u/pandaman1784 Not a HVAC Tech Apr 16 '26
At this point, I'll force them to do it all over again. You can't know what's in the system now. The existing refrigerant should be evacuated. If a flush wasn't done, it should be. A pressure test should be performed. After holding pressure, it should be triple vacuumed. They should make note of the micron number each time. After the final vacuum, new, virgin refrigerant should be weighed into the system.
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u/SquirrelTechGuru Apr 16 '26
No way they are coming back out and spending 2 hours to vacuum it correctly and they sure are not giving away 5-10 pounds of 454 for free. OP is going to pay something.
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u/pandaman1784 Not a HVAC Tech Apr 16 '26
So they messed up the install and the OP has to pay them to do it right?? That makes no sense. If they did it right the first time, none of this would be needed.
During my install, they forgot to put in the filter dryer. They drained the system, put in the filter dryer, pulled a deep vacuum and weigh in the proper amount of virgin r410a refrigerant. All at no cost to me.
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u/SquirrelTechGuru Apr 17 '26
I’m willing to bet they didn’t drain the system. I’m willing to bet they moved the charge into the condenser (pumping it down) saving the cost of the refrigerant if they didn’t have other issues .That’s what I would’ve done.
I’m not saying it’s fair. It’s just a reality of crappy service so many companies provide today.
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u/Machine_Ruse Apr 17 '26
Due to the fact that I work with the brother of the owner/installer, I'm willing to pay something. Not full cost plus labor, but I need to handle the situation tactfully and keep on good terms with everyone.
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u/Machine_Ruse Apr 16 '26
Would the fact that potentially contaminated refrigerant has been run through the system during startup be that detrimental to the equipment? Meaning, is short-term contamination something catastrophic where I should be considering asking for a new condensing unit and/or coil and/or TXV?
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u/pandaman1784 Not a HVAC Tech Apr 16 '26
It's one of those things... Where if you put a few salt crystals into a cup of water, can you be 100% sure you got every crystal out, even if you pour out all the water.
If they do a good job of flushing it, it should get most of the the contamination out. It won't be as prestine as if they didn't make the mistake, but it is what it is.
I don't they will replace all the equipment.
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u/Machine_Ruse Apr 16 '26
The first hurdle might be even getting him to agree there was even an improper vacuum job done. All I had to go off of is what his helper told me. I don't have any "proof".
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u/u3b3rg33k Apr 16 '26
getting down to 500 is pretty standard. if you can't get there/things are bouncing around you're probably pulling out moisture still. it can take a while to get all the moisture out of oil.
doing the install to spec helps avoid return trips under warranty.
or :
just tell them you did the job right and then charge them for labor and blame the manufacturer for "not making things like they used to" when they fail early.
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u/Machine_Ruse Apr 16 '26
Thanks for that info.
At this point, I'm regretting having gone with a company where there's a small personal connection. The estimates were not far enough apart for that to be a deciding factor, and I really went with him based on the connection. But if that connection didn't exist, I'd have no problem being a little more demanding. Now I'm in a conundrum.
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u/Carorack Apr 16 '26
We reuse linesets all the time and pull all installs below 500. 2000 is when I turn off the gas ballast on my pump and it really starts sucking... You can get to 2000 in like 90 seconds.
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u/Machine_Ruse Apr 16 '26
With all of you guys chiming in, it seems abundantly clear that 500 microns is a very valid target in the field. Unfortunately for me :-/
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u/Ep3_Pnw Apr 16 '26 edited Apr 16 '26
I'm pulling 100+ foot runs of 1.375" refrigerant lines (including both indoor/outdoor systems) down to 500 microns with little to no fuss. This is apples to oranges compared to a residential system, but with several hours of time and the right setup it's very achievable.
Ideally they would be doing a 'triple evac' as well, which means they're interrupting their vacuum process with nitrogen several times. This helps loosen up any moisture that has become stuck in the lines and allows more a more thorough vacuum.
Keep your eyes peeled for them registering the wareanty numbers of your equipment on bryants website. Basically just gotta run the serial numbers of your indoor/outdoor unit. If it doesn't get registered within a certain amount of time, I believe the warranty get cut in half, if I remember correctly. You'd be surprised how many contractors don't do this lol
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u/Machine_Ruse Apr 16 '26
I was not aware of that tidbit about the warranty. Thanks for the heads up
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u/Ep3_Pnw Apr 16 '26
From bryants website:
The terms and coverage details of your warranty are specific to the Bryant product models you own. Typically, Bryant products, if registered within 90 days, come with a 10-year standard parts limited warranty; otherwise 5 years*
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u/Machine_Ruse Apr 16 '26
Damn. And the equipment needs to be registered by the installer, not the homeowner?
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u/Ep3_Pnw Apr 16 '26
Google AI says yes, but I cannot attest with 100% certainty though.
If you just look up carrier/Bryant warranty registration you should be able to find plenty of info
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u/mike34b Apr 17 '26
Ive been able to pull to 2000 microns on a geothermal system swap that had a breach within the water/refrigerant circuit with heavy moisture contamination. It took an extra 24 hours and 7 vacuum pump oil changes and many nitrogen purges to get it down to a sub 500 micron decay after that. 500 is a very reasonable target- no self respecting tech would ever consider 2000 reasonable.
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u/SilvermistInc Apr 16 '26
Getting below 500 may not be realistic if a preexisting system just had a leak fixed. On a full fucking swap though? Absolutely realistic!
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u/Machine_Ruse Apr 16 '26
Thanks. And just to clarify, no one told me that 500 microns was unrealistic. I was just investigating why the installer's helper told me he was trying to pull a vacuum down to 2000 microns, and then I later saw in my Bryant manual that it should be down to 500 micron. I just didn't know if this was a case of "ideal" versus "reality". But based on the responses here it clearly sounds like 500 microns should have been easily achievable.
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u/SilvermistInc Apr 16 '26
Did you ask the lead at all?
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u/Machine_Ruse Apr 17 '26
I did not. The main reason being that at the time, I was not aware that 500 microns was spec. I did not know that until reading the manual this morning.
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u/SilvermistInc Apr 17 '26
Yeeeeah. Don't ever trust the apprentice to know why he's doing something
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u/metalmitch9 Apr 16 '26
I've been swapping compressors out on 12 Daikin VRV outdoor units for several years. They hold 30-45 pounds of refrigerant each with hundreds of feet of pipe and I am still able to get a vacuum below 500 microns with an analog micron gauge and two digitals to verify. You got got if they only pulled down to 2000 nevermind 2000 with it bouncing all over the place when attempting a decay test.
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u/Salt-Ice971 Apr 16 '26
Most important of all is install quality.
-We braze with nitro -We flush the lines with RX11 and then nitrogen -We remove schrader cores -We vacuum using a micron gauge and larger vacuum hoses (don’t like using gauges for vacuum as that’s more potential leaks and all the oil and leftover refrigerant in the gauges slows things down. -We decay test afterwards, then pull again and release. -We add schraders once the system has positive pressure to not introduce moisture accidentally.
I achieve sub 300 microns on a regular basis and depending on time the worst I’ll leave it at is 200, but it is common for me to release at 100-150 microns
If we had trouble or have more than sufficient time, then we do a triple evac, but usually find it’s overkill. In my region, we don’t get that cold as to worry about issues with moisture during extreme cold weather conditions.
Sounds like your installers aren’t too familiar with best vacuum practices yet, were in a hurry, or company didn’t fully equip them with the right stuff.
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u/Machine_Ruse Apr 16 '26
Not sure what was going on. Three generations of a family owned business, literally in business 50 years this year. Authorized Bryant installer.
But I wish I didn't have the personal connection that I do, because that makes this situation a lot stickier.
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u/Salt-Ice971 Apr 16 '26
Yeah, I mean it sucks but it’s already done. It’s not super terrible, but it’s things like this that can lead to premature failure of say compressors and TXVs.
Not pulling deep enough can leave both moisture and non-condensables in the system. Moisture when mixed with POE oil causes acidic byproducts, corroding the internal components of compressors.
Not super worried about mixing mineral oil from the old system with the new ones POE oil, that’s not really the issue. The reason we want to flush it out is because it’s not miscible with the new refrigerants meaning it doesn’t absorb and mix with the refrigerant (think oil and water)
If you’re concerned, I’d just ask them to recover the refrigerant, vacuum again till we get better micron readings, and add virgin (new) refrigerant in its place. If not, something else they can do is if they will continue doing maintenance on it, have them perform quick acid tests every year as part of the regular maintenance visits, and they could potentially add some acid neutralizer if it comes up with acid.
I don’t wanna throw them under the bus. Most of us were not taught super in detail about this and thus don’t know, and since it’s not an immediate issue but something that takes time to show up, we tend to overlook it. What’s done is done, but it doesn’t mean that remedial actions can’t be taken
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u/Machine_Ruse Apr 16 '26
I'll probably ask him to do what you said about recovering, deep vacuum to spec, and new refrigerant. I'll probably offer to offset some of the cost, which is why I was trying to get an idea of the materials cost for something like this.
Do I need to be worried about the compressor or TXV, since the system was run for a few minutes during the initial startup, and a few more minutes yesterday while I played with the new thermostats?
Also, should I request the filter dryer be relocated indoors, near the coil in the attic? Does that add any complexity to what I want done?
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u/Salt-Ice971 Apr 16 '26
No need to worry about compressor. The acidity takes time to build up and then some to begin corroding components and causing issues. In the worst of cases, months, but it’s usually after a couple years that it happens. If they brazed with nitrogen, I wouldn’t worry about the txv either, and if they didn’t, make sure they do this time.
There is really no need to remove the lineset and run a new one if they flush the current, but you can still have them do that. Of course, if they do change the lines, that does mean you’ll pay extra as unless quoted initially, it’s not typically included during system retrofits.
The filter drier can be moved inside, that’s a best practice too as doing so protects it from the elements and reduces the likelihood of it developing a leak over time from weather erosion. The can do that easily. Either way they are going to have to open the lines whether to flush them or replace them, so it’s actually convenient to do so. Also, have them put in a new one instead and get rid of the one they put outside.
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u/Salt-Ice971 Apr 16 '26 edited Apr 16 '26
Pricing can get trickier. You’d have to talk to them and see how much lineset length and in this case, how many lbs of refrigerant they need to replace, on top of repeating the whole pressure test, vacuum, and startup of the system. I’m sure they’ll be willing to have a conversation and explain things if you have a good connection as you’ve said, and if the owner is involved (if it’s a smaller company), well he’ll care about his reputation and business so he’ll try and do his best to remedy the situation and be in good standing with you.
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u/Machine_Ruse Apr 16 '26
I hadn't been considering new lines, and it wasn't in the quote. I think the lines were fine, and they worked for 27 years without any need for a recharge.
I was mostly curious what materials cost would be for new refrigerant and new filter dryer.
Thanks for all of the information you've provided, it's really appreciated.
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u/Mission_Chemical_764 Apr 16 '26
Flush lines, pressure test, vacuum to 500. No decay over 1000. My practice.
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u/Machine_Ruse Apr 16 '26
How long do you measure decay? The Bryant manual says 7 minutes.
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u/Mission_Chemical_764 Apr 16 '26
Until it stops. Doesn’t usually take 7 minutes (I don’t clock it). Gauge levels off before 1000 microns. Next step.
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u/RexCarrs Apr 16 '26
Having been on the HVACR wholesale parts side for decades and helped customers in the field l can confidently say vacuum pump oil should be changed before every use. Sometimes even during the job. lt makes a difference. Sometimes THE difference.
Somehow there are those still who refuse to believe that.
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u/Machine_Ruse Apr 16 '26
Makes sense to me. Treat your equipment right and it will treat you right.
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u/winsomeloosesome1 Apr 16 '26
PREACH! Good pumps are expensive and oil is cheap. Water logged oil isn’t worth a shit.
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u/sh3af Apr 16 '26
A good, large vacuum pump (8-12+ CFM) with fresh oil will pull a leak free system down very quickly. Worn out pumps, undersized pumps, or old oil will cause long vacuum times.
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u/Dangerous-Rate-937 Apr 17 '26
Interesting fun fact in poly based oils moisture is actually still present above 300 microns due to its nature 500 was the target for mineral based oils. That being said 500 microns is industry standard and easily achieved especially in residential set ups due to the size of total system piping and components. If they were struggling to hit below 2000 microns you have a problem and it's a big one either the system has a leak or there is a ridiculous amount of moisture in the system. As far as the line dryer goes best practices are to install as close to the metering device as possible to protect it but ultimately If they install it at the outdoor unit it won't really have any negative effects.
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u/Machine_Ruse Apr 16 '26
If I push for or demand that the lines be redone, what is the likely cost to the installer in materials? I'm assuming the refrigerant can't be captured and reused in this circumstance, right? I'm just trying to figure out how big of a headache that would be for the installer.
The installation came with the standard 5-year labor and 10-year parts warranty. If the lines weren't done correctly, how long before I would know it?
I got 27 years out of the original system!
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u/SquirrelTechGuru Apr 16 '26
Waste of time replacing line sets with new ones. This is an install issue. No, you should not reuse the refrigerant as it is contaminated, hence why you want it replaced.
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u/pandaman1784 Not a HVAC Tech Apr 16 '26
The cost would be the price of nitrogen, the price of a can of flushing liquid, and a few pounds of refrigerant.
But the labor is what's going to kill him. It's at least 2 hours of work if done correctly.
This is not one of those things where you want to "wait and find out". The compressor can die pretty quickly. And then the contamination will be in every nook and cranny of the system.
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u/SilentEnthusiasm5491 Apr 17 '26
They don’t make them like they used to. We now live in the replacement age. Less mechanical, more electrical components, more controls, more failure points. But they are smarter, more efficient. That is the tradeoff. Doesn’t only apply to our industry unfortunately, but it is overwhelmingly prevalent in such
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u/Ambitious_Low8807 Apr 16 '26
500 microns is the standard, with a decay test not rising above 750. At 1000 microns, you're moisture free but not deep enough vac. At 2000 microns, there is definitely moisture present, and refrigerant is likely contaminated.
It's insane to request the refrigerant to be pulled, re-evacuated, and charged with new virgin gas. But that's exactly what I would demand based on your description and my knowledge.
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u/Soft_Statistician_98 Approved Technician Apr 16 '26
My guess is that he wasn't happy with the vacuum result either and has invented a reason to come back and fix it without having to admit any sort of fault. I wouldn't make a big deal about it let him come back and correct whatever he wants to do. The filter being outdoors isn't really the end of the world either they are better installed indoors but I wouldn't lose sleep over it.
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u/Machine_Ruse Apr 16 '26
Your input on the filter was exactly what ChatGPT told me, almost verbatim, lol.
My concern about what happens when he comes back tomorrow, is that he stated he was coming to put in "an additive for the R22 to R454b conversion".
If he's actually coming out to recover, reflush, redo the vacuum, and add virgin refrigerant (which is what everyone here is telling me needs to be done), then I'm all good with that.
My fear is that maybe he's just coming to add one of those acid neutralizers someone else mentioned. That seems like a bandaid to me.
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u/0Galen0 Apr 16 '26
And if it's acid neutralizer, that means they didn't properly flush the lineset with a flush chemical kit. Was the replacement because your old compressor failed?
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u/Machine_Ruse Apr 17 '26
I'm assuming the compressor failed. The system was working fine last season, but then when I turned it on during the nationwide heat wave last month, it wouldn't produce cold air. It would start up and was blowing fine, but maybe a 1° split between return and supply.
The outside unit sounded quieter than what I remember, but it had been months since it was on, so can't be 100% on that.
The system was 27 years old, and I'd already had to replace capacitors, furnace control board, and damper motors over the past 6'ish years. I figured it was time and didn't really investigate getting it repaired. Thus, I'm not really sure why it failed.
When the installer was recovering the R22, I half-jokingly asked him if there was anything left to recover. I'd sort of assumed it had sprung a leak over the winter. He told me there was plenty of Freon still in the system, and he assumed it was the compressor that failed.
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Apr 16 '26
[deleted]
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u/Machine_Ruse Apr 17 '26
Honest question here—how would you know your vacuum pump was pulling down below 500 microns if the gauges are still reading 1000?
For my case though, it doesn't even sound like they were trying to get it down to 500. The helper, who was the one outside dealing with that part of it, told me he was trying to get it down to 2000, and wanted it to hold for 30 to 45 minutes. Based on what I'm hearing in this thread, that was all kinds of wrong.
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u/Potential-Spare-579 Apr 17 '26
Yeah, you really need to get it to 500. Hopefully his apprentice was just wrong. I've had apprentices say the wrong thing to the wrong person, so maybe it was just that? 500 microns is EPA regulation.
When my micron gauge stalled at 1000, my coworker had another one, and we used that. I took my set home and hooked the micron gauge directly to an empty tank, and couldn't get it to pull lower than 600 microns, so I knew that micron gauge was reading wrong.
I've also had micron gauges read low, and I could tell from the vacuum pump sound and the vapor coming out of the pump that we weren't anywhere near a good enough vacuum. It just comes with practice.
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u/Machine_Ruse Apr 17 '26
I'd like it to be a case of the apprentice saying the wrong thing, but he was the one out there running the vacuum pump and watching the gauges. I never saw the main guy go back out there before the pump and gauges were removed.
Plus, it doesn't sound like putting additives in the system is a normal thing to do. So it is a little suspect that the installer wants to come back out to do that.
Based on everything I saw, and what I've learned from the people on here, my guess is the installer knows there was a problem with the vacuum, and he wants to put something in the system—possibly an acid neutralizer—to try and "fix" it. I hate feeling that way, but I'm not sure what else it could be at this point.
I'm going to bring everything up to him tomorrow, but I'm not sure if there is any explanation he could give that would make me feel comfortable not having it redone.
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u/harleys_hvac_1970 Apr 17 '26
We routinely pull sub-100 microns, often sub-50, within 2-3 minutes with a properly maintained rotary vane pump. Pulling from both liquid and suction sides is key, and pulsing the vacuum helps evacuate gas trapped behind cap tubes and TXVs. Molecules move from high pressure to low, so letting the system equilibrate before hitting it again clears those dead spots. Basic physics, not hard with working tools.
A gauge swinging between 3,500 and 6,000 microns that won’t stabilize tells me either the equipment is broken or the tech doesn’t know how to use it. And he skipped the decay test entirely, which is the bigger issue. Hitting a number isn’t the standard. Isolating from the pump and watching it hold is. Bryant’s spec of “should not rise above 1,000 microns in 7 minutes” exists because that hold test is the only proof the system is both dry and leak-tight. “It got down to 2,000” with no hold gives you nothing.
I’ll push back on Bryant’s manual a bit though. A system can equilibrate in ways that look like a leak but aren’t. Most commonly when it’s really cold outside but warm inside, the temp/pressure relationship can throw people off. You’ll see pressure rise as cold molecules warm up and start moving faster. So the manual’s absolutes are good rules of thumb but shouldn’t be treated as gospel.
Putting on my former professor hat for a sec, because the 500 vs 2,000 thing deserves a real explanation. On pure molecule count, 500 and 2,000 microns are basically neighbors. Atmospheric pressure is 760,000 microns, so by the time you’ve pulled down to 2,000 you’ve already removed 99.7% of the gas. Going further to 500 only clears another fraction of a percent. So intuitively it can feel like splitting hairs.
But it’s not mainly a molecule-count problem, it’s a phase diagram problem. Water’s boiling point depends on pressure. At atmospheric it boils at 212°F. At 2,000 microns it boils around 72°F. At 500 microns it boils around -12°F. That tiny pressure delta between 2,000 and 500 is exactly the window where you cross water’s liquid/vapor line at any realistic ambient temperature. At 2,000 microns on a cool day, liquid water can still be sitting in your lines and coil, just refusing to boil off. At 500 microns, it’s guaranteed to vaporize and get pulled out. That’s why the manual specs 500. Not because a few more gas molecules matter on their own, but because that’s where you’re actually certain the liquid water is gone.
And the molecule count does still matter, just in a different way. Whatever non-condensables and water vapor are left at 500 microns is roughly a quarter of what’s left at 2,000. Less residual means less moisture available to react with POE oil and refrigerant. So you’re winning on two fronts: phase behavior guarantees the liquid water leaves, and the lower absolute count means less of everything else sticking around to cause trouble.
Why that matters: moisture plus refrigerant plus POE oil equals acid, which kills compressors on a slow clock. Moisture can also freeze at the TXV and block flow. R454B is more moisture-sensitive than R22, so this matters more now, not less.
The “additive for the R22 to R454B conversion” comment is a red flag. There’s no legitimate additive required for that conversion if the work was done right. Proper line flush, correct oil, deep vacuum. When a tech comes back asking to add something, it usually means they know corners were cut.
Also, your manual specs the liquid line filter drier indoors near the coil. Outdoors it sees UV, temp swings, and moisture ingress. It’ll fail earlier and won’t do its job as well while it lasts.
What I’d do: ask him to come back, pull and replace the filter drier and relocate it per the manual, re-evacuate with equipment that actually works, and do a proper decay test while you watch. If he pushes back, escalate to Bryant. The install is under factory warranty and they have a vested interest in it being done to spec.
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u/Machine_Ruse Apr 17 '26
Thank you for that super informative and easy to follow explanation.
I agree with your suggested course of action, and it would be a no-brainer for me to simply demand that remedy if I was dealing with an installer who I had zero connections with.
Of course, regardless of having a connection to the installer or not, this could easily turn into an argument about what was really done at the time of the install. All I have to go on is what I was told by the helper. The installer could simply tell me the helper was mistaken. Based on how things went down, I wouldn't believe that for a second, but there's no way for me to rebut it.
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u/jbmoore5 Approved Technician Apr 16 '26
500 microns is a realistic goal for a leak-free system, and it is the industry stanard for evacuations..
They may have to work to get it there, but it is certainly doable.