Do NOT use the box store contractors for ANYTHING, EVER, including flooring, tile, etc....

They are one step above home warranty contractors in terms of quality. Pure garbage.

Sorry I missed your post. Hopefully this gets to you in time.

Yes, everything your tech said makes sense.

20yrs is a good lifespan for HVAC.

Amana is a solid mid grade unit. I would install one in my home. Good warranties.

Dang, this thread has just turned 10yrs old.

Not much else to say except let the pros do their work and track down what has failed.

I have never had many issues with Trane’s boards.

I hope it’s something easy and not too expensive.

The on call guy is not looking forward to his 4pm Friday call.

There is always the risk, and there is little you can do to limit your exposure to those guys.

Trust your gut and ask the guy to leave if the alarm bells are ringing.

20.5 x 1.75 x 2 = 71.75 sq/in
32.5 x 1.75 x 2 = 113.75 sq/in
Round this up for easier math
72 + 114 = 186 sq/in for air to flow through that funky grille.

Same as a 10x18 duct = 180sq/in.

Now let’s put that on a ductulator and see what you flow at .5” of static pressure which most residential systems are designed around (max). 3” is more better though.

10x18 duct at .3” of SP is pushing 2000cfm. 400cfm per ton = 5 tons.

One outlier is how long of a ducting run from the furnace to the grille?





FYI: Ducting design and air balance is not my strong point, please have this checked before doing that install.

Lots of ductulator apps for phones out there.

Not a ton of experience, no opinion either way.

I wouldn't

https://www.honeywellhome.com/us/en/products/air/thermostats/wifi-thermostats/wifi-9000-color-touchscreen-thermostat-th9320wf5003-u/

Stay away from the Google Nest. From my understanding, that thing is a spy machine in your house.

I’m sure the Honeywell is also gathering and selling data, but I just don’t know about it.

Turn power off at the furnace or air handler.

Wire for wire, mount on the wall, program.

Power back on.

Test operation.

@ZW17

Apologies in advance for the "War & Peace" tl/dr story here...

I have a significant: "I'm poor/broke, with a bunch of ad-on 'There's a hole in the bucket dear Liza' stuff,"-AC problem. And I feel as if my options are to do something janky & DIY I can afford, or do nothing, and limp indefinitely on window box AC's, which, I need anyway, more on that below.

I have a 1929 Milwaukee 'burbs craftsman 2-story bungalow. Roughly 1800 sqft. With 3/4's of the basement finished.

I and my wife bought it in 2000. It came with a 1997 vintage Bryant nat. gas non-efficient forced air furnace. And it has an R-22 A-frame upflow evaporator with 2.5 (you may already see an issue...) ton capacity.  And a Bryant brand condenser outside in the back yard.

On the heat side, I've gotten very very good at troubleshooting all the various proof-of-flame thermocouple, vacuum airflow diaphragm switch, fusable link overtemp cutoff, ignitor glow plug aging, & insufficient voltage & resistance, the whole damn mainboard, and motor stater capacitors.

In 2010, in the middle of a hot summer, with four young daughters, back-to-back twins, 11 months apart, the AC died. And Mrs. Dual & I needed that fixed ASAP.

I already knew enough to troubleshoot decently, and followed the issue to the condenser. Corrosion & dirt allowed the start capacitor to arc into the main compressor capsule when it attempted to start, and besides the short preventing startup, it actually melted a hole into the compressor pod, and all the R22 had vented.

We called a local well regarded HVAC company, and the estimator/service writer was a good guy, and explained what was coming up with the stages of the R-22 ban, and what our options were. And he understood our need for a minimum effort & minimum cost repair.

So they did a dry-nitrogen filled generic OEM condenser, keeping the original '97 Bryant A-frame evaporator, because some of it had to stay to make it a legal "repair" to use R22 for a recharge. So they sweated the OEM dry N2 condenser on, and recharged it. All for $3500. Parts & labor.

Which I believe was an average & okay price. And I appreciated them understanding we could only afford the minimum, not being pushy or upselling, plus the R22 grandfather repair issues.

Now, in 2024, I'm a widower, down to one income, with four girls in college.  And I ain't got the $3500, even if that sum would fix my AC, which it won't.

This year, the condensate drain was plugged up inside the drip pan under the evaporator. I was careful as possible to not move anything other than the sheet metal to gain access. I scraped/flushed out all the moldy Legionaire's Disease snot, and since I was in there, I sprayed down the coil with no-touch coil foam cleaner.

I did have to move the coil a little, just an inch or two, letting the big copper cold side supply and little copper hot side return do the bending, ensuring they didn't kink.

Did I just whiff something minty + magic marker smelling? Ohhhh shiiit.

Smell again, repeatedly, nothing. Shut off every noise in the house possible, listen, nothing. The foam cleaner & rinsing was a decent soap bubble check too. Nothing... (At least on the sides of the evap. I could see without risking even more big movements)

Okay, I'm just paranoid... probably.  Close it up, throw the breaker for the condenser, turn HVAC stack power on, make sure the WiFi thermostat is calling for AC... It starts up, blows cold air, and the condensate tube is draining nicely.

Next morning, AC is blowing, but it's not cold.


Micro cracks or pinholes in the evaporator, dissimilar metals corrosion between the copper, aluminum, steel, lead/tin soldering, and the coil was nearly 30 years old.

I get it.

But, being broke-ass widower me, I can probably only swing the price of parts... if I can make it work. That would be keeping the newer 14 y.o. condenser, as I've neuroticaly kept it covered in winter, and clean, like Cameron's Dad's Ferrari in "Farris Bueler's Day off" after what happened to the first one.

So sweat on a new R-22 & "compatible multi-refrigerant" upflow 2.5 ton A-frame, and charge it with R-442D/MO59, assuming I can find a small non-rape priced 5 lb. bottle just for me, as I don't need 20 lbs. to service a few houses. And assuming there's not a MO oil vs. R-442D vs. POE oil problem, that means I can't do any of that.

The house came with only a 2.5 ton AC because everything the previous owners did, and what little they paid anybody that was a pro in the relavant trades to do... was bare-minimum cheap, DIY, & shitty "Mad Max Master-Blaster runs Bartertown!" or maybe, "Gilligan's Island bamboo & coconuts style" remodeling & upgrading.

Siding, roof, gutters, windows, doors, trim, insulation, electrical, plumbing... I could write a post as long as this about each of these.

And that includes the forced air ducts. No balancing whatsoever, nonsense cold air returns, or none. And they were merely proud they figured out a way to get a duct to each room with as little upset to walls or carpentry as they could. Too many 90° bends, shape & size changes, or, no duct at all. Just using the void between two studs and the plaster, lath, or drywall as a riser.

All stuff I had no clue about when I was 26 years old back in 2000. Nor did I know that many "home inspectors"... most just collect a check to sign off on bank & insurance paperwork, and only look for obvious things that'll break in under a year, or might kill the homeowners with CO asphyxiation and get them sued.

So there's no point in upgrading the whole HVAC stack, unless I can also afford a bunch of demolition & repairs so properly done ductwork can go in. Or, maybe they demo my old brick coal/oil furnace chimney the furnace & gas water heater use still use. And the void from removing it, could be ysed to run those narrow high-velocity air flexi ducts. If they're even a thing, or still "in fashion."

@AJ_Dual

I read you book, you have a way with words, it was funny.

But is there a question in there that I can answer?

If you are asking what to do... If the ducting has been working for 20+ years with 75k BTU's (guessing, you didn't say) of heat and 2.5t of cooling. I say replace the minimum of the furnace and AC. I mean you need it, you really can't get away without it, and you're not paying to reinvent the wheel.

Mini splits are an option, but you will need new electric run all over the house to support multiple systems, or big power run to the condenser and refrigerant lines run through the home to the evaporators.

I think your most economical route would be to swap out the existing gas furnace and AC.

Thoughts?

@ZW17

Thanks for replying! And again, I'd so gladly pay to have this done. It's simply a matter of its DIY this at parts-cost, or do nothing, essentially. And your reward is... shit. Another novel.

I agree that the most economical approach is replacing the minimum of the HVAC too.

And yes, the AC pushing cold air up against gravity, with bad slow ducts and an inadequate 2.5T AC sucks, but "just live with it" is okay. Especially since at least heat passively rising in winter more or less works out okay, leaving none of the 2nd floor rooms freezing.

And on this plan, the furnace stays. It works, and except the one time in 2014 the main board died, it's all been common replacement parts, sensors, and the main blower start capacitor...

So my concise, pointed question is... My idea of spending about $800-1000, for:

1. An R-22 & "compatibles" 2.5T A-frame upflow evaporator that fits, same dimensions as the old one.
2. Keeping my existing R22 condenser outside.
3. Getting a $100-ish Amazon or Harbor Freight hi/lo manifold testing & recharge/fill gauge & hose set.
4. A small 5lb bottle of R-224D/MO59...

Is that possible? Any immediate problems or incompatibility?

Additional questions:

- Is there a problem with the R22 condenser if it has mineral oil in it, if I fill with R-224D that has POE/synthetic mixed in the bottle? (I assume it's just in the refrigerant, right? And it sprays or carries in with a fill or recharge? Seems like an assumed thing "you are supposedto already know.")

- If existing MO in the compressor, coils & lines IS definitely "a no-no," either because it shouldn't be mixed with POE, or the R-224D, or both (Everybody's explanation on this  all differ, and it is unclear. There's no nice OK & NOK matrix grid of combinations covering all combinations.)

- Is there a definite way to confirm if my existing R22 dry N2 replacement compressor has MO or POE in it? From a tech datum on its labels? Some other way?

- If this is all OK and in theory is compatible and "should work" (not counting if I actually screw up doing it somehow, of course) are there pitfalls and scams I should be aware of? Vendors to avoid, vendors to trust? Anything about trying to buy a bottle of R-224D I should be aware of?

- Just Googling possible items, and seeing the search results, sets off my spider sense. Even though I am searching on R-224D/MO59, there's tons of listings for R-22 at very good prices.

Like WTF is this below? I assume it's a China based website, so are they just doing the: "IDGAF, ship it, see if it makes it through CBP to the US buyer?"-thing?



AFAIK, it's supposed to be illegal/phased out worldwide, with only narrow exceptions? But...China is probably DGAF on that too, and the grandfathered supply, or very limited "nothing else works" exceptions, they just wholesale abuse that?"

So, even if my minimum parts, zero labor idea is technically feasible, I worry there's another whole layer of fly by night scamming. And the top selling hits for things like: "Upflow A-frame R22 2.5 ton 18"x17"x20" turn up this: https://www.acwholesalers.com/Goodman-CAUFA2922B6/p114284.htmldXxoCvDMQAvD_BwE

This is a fly-by-night borderline scamming place? I'm not even saying it's exactly the right evaporator... just an example.

But I have a hunch, and it all makes me think there's a large scammer or legal-but-shady Industry aimed at fleecing guys that are either stungy/cheap, or desperate & broke (me) and have "some idea of what they're doing" but aren't full-time HVAC guys in the know. Or, it's a drop-shipping front, trying to refer you for installation through a HVAC service network with kickback comissions.

You are not supposed to mix oils, it's not the end of the world if you get some containments in there, but I wouldn't be putting an entire compressors worth of oil in a system. Gelling was the major concern, and once that happens, you are in a world of trouble to try and clean that up.

Dry ship (nitrogen filled) is still out there but very hard to find. If you can locate it, it should be fine. I cannot recommend one brand over another, I honestly haven't bought any dry ship equipment in years. R22 has been dead in the commercial/industrial side for years. Our customers equipment has sometimes hundreds of pounds of refrigerant, they changed over to R410, R407, and R134 years ago.

I would recommend replacing both the evap and condenser, it's a few hundred more for the condenser with the cheaper lines of equipment. No sense in hacking the system up to save $400, but I don't know your financial situation.

Harbor Freight stuff will get you through a job or two, it's really your only option unless you have somewhere that rents near you?

To recap:

- Don't mix oils, not a good practice.
- Recommend spending the money to move away from R22 everything and bite the bullet and go to newer refrigerants.
- Harbor Freight will get you by in a pinch.
- Don't buy the overseas R22, it's both illegal for you to ship and it's quality would be questionable.
- Every manufacturer has off brands (Carrier is Bryant, is Payne). Go with a lesser brand like Payne and save hundreds for basically the same equipment.

Sorry, in an end of the week rush at work, I wish I had more time to give a more thorough answer.

No such formula exists that I am aware of.

Each house needs a custom manual J to determine these factors.