$680 zoned HVAC instead of $5000 central system

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Re: $680 zoned HVAC instead of $5000 central system

Postby nutspecial » Wed Sep 06, 2017 7:48 pm

Thanks; I'm really green on the subject, but I was assuming brazing was specifically suited for joining dissimilar metals? I'm not sure how many, but I guess there's at least four common ones, and brazing modernly still has benefit in specific areas like this?

For copper to copper in plumbing I've always used solder and a torch. I'll have to look into what you're talking about to zero in on specific applications and procedures- it sounds interesting thankyou!
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Re: $680 zoned HVAC instead of $5000 central system

Postby spinningmagnets » Wed Sep 06, 2017 7:58 pm

Resistance soldering/brazing...Here's an example, very short video. Activated by a foot-switch, and amps are adjustable according to the size of the work-piece.

https://www.youtube.com/watch?v=qjNHCxvB8Kc

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Re: $680 zoned HVAC instead of $5000 central system

Postby Matt Gruber » Sun Sep 10, 2017 3:01 pm

So my plans are evolving. two of the reasons to use 5k btu ac's was they are usually the quietest and lightest. this device eliminates the need to not be heavy:
http://www.ebay.com/itm/440lbs-Mini-Ele ... 2749.l2649
now i see that 5 ac's would have a heck of a lot of ducts, so and drain plumbing, so now i'm free to use larger ac's.
Have 8k btu GE on order. recommend by consumer reports, and 92%. Got it from jet $138+ tax, free ship.
this drops the 5 down to 4.
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Re: $680 zoned HVAC instead of $5000 central system

Postby Matt Gruber » Tue Sep 12, 2017 6:23 pm

Just got the GE 8k ac. a quick test and it makes less noise than my vacuum :roll:
if this was going in a window, i'd send it back.
68-73db.
but, behind a wall in the next room, only 48db. so i guess i'll give it a try for kitchen DR and den. i plan to run it for an hour or so before going in there, and then shut it off when in those rooms. Heck, i shut off my fridge and it is 48db. i'd rather hear my music without having to turn it up.
So no more big units for me. good thing i got it for 138 and didn't buy 2.
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Re: $680 zoned HVAC instead of $5000 central system

Postby nutspecial » Wed Sep 13, 2017 9:54 pm

68-73db

Wow is that like at 10ft? They all seem loud to me though, and never tested decibels on a standard box fan to compare (or much at all, beyond loud 100-110 stuff). Good thing your design minimizes any negative impact from noise for user!

Personally I can only 'handle' hearing a fan, like from a minispit, (or a normal fan), or the air moving thru vents. The various compressors' hums somehow can be annoying, at least in close comparison. Not sure if it's just frequency.
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Re: $680 zoned HVAC instead of $5000 central system

Postby Hillhater » Thu Sep 14, 2017 1:31 am

Yes, a fan has to be big and slow,.or very remote, to be quiet enough to tolerate.
Even the latest brushless 48" ceiling fans i have installed are only tolerable at the slower speeds ( <100rpm ?)
not fanblade noise though, but a gentle buzz, most likely from the controller ?
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Re: $680 zoned HVAC instead of $5000 central system

Postby Matt Gruber » Fri Sep 15, 2017 9:57 am

nutspecial wrote:
68-73db

Wow is that like at 10ft? They all seem loud to me though, and never tested decibels on a standard box fan to compare (or much at all, beyond loud 100-110 stuff). Good thing your design minimizes any negative impact from noise for user!

Personally I can only 'handle' hearing a fan, like from a minispit, (or a normal fan), or the air moving thru vents. The various compressors' hums somehow can be annoying, at least in close comparison. Not sure if it's just frequency.


68 is at 3'
73 is close.
actually, in a window much of this compressor noise is outside; that must be how it gets high ratings.
So, i've researched noise suppression, and have an idea i want to try. I have some 3/4" flake board that i got for free, but i never used it, in 15 yrs, until now. It is really heavy, like 100# if i had a whole sheet, which i dont; just leftovers from a job. i'm going to box in the outside section, really big, like 34" wide, while the ac is 19" wide. and 21" high vs. 12.5. the heavy case is the sound barrier. I'll cut a single 12" hole for the outside duct. 1 hole instead of 4 dozen slats which radiate the comp. noise. The duct will be r6 fglass covered; std HVAC duct. i'll cover the outside of the case with the SafenSound Roxul batts.
Then it will be easy to duct in air from the window to keep it cool. And should be much less noisy. In the winter it will be easy to connect a 12" return duct. BTW, 12" is way oversize, maybe 8" could do it, But ac experts say ducting mistakes are always going too small, and you can't really go too big. It will cost an extra $20-40, I don't mind spending extra on the ducts, since i'm saving like $4000 on the whole system.
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Re: $680 zoned HVAC instead of $5000 central system

Postby vanilla » Fri Sep 15, 2017 4:14 pm

Have you looked into conversion to propane for the r22 system? I've heard good things.

Back when I had central heat installed I decided against the A/C because I knew I'd use it if I had it. I later got a roll around unit that eats maybe 1500 watts. Great for the few really bad days. It only cools one room, but that is all you need really to hide out from the heat.
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Re: $680 zoned HVAC instead of $5000 central system

Postby Matt Gruber » Sat Sep 16, 2017 9:34 am

vanilla wrote:Have you looked into conversion to propane for the r22 system? I've heard good things.

Back when I had central heat installed I decided against the A/C because I knew I'd use it if I had it. I later got a roll around unit that eats maybe 1500 watts. Great for the few really bad days. It only cools one room, but that is all you need really to hide out from the heat.

i saw a video on propane. interesting! But my 3 replacement ac's should last many years, and 2 use the cheaper r410a. The one that uses r22 will likely be thrown away when it fails. Why try to fix an old ac that cost $79 new?
the main idea here is to eliminate repairs/service calls, have a better system, and spend 80-90% less on hardware. ......and to have a new hobby where i learn something new every day, at least until the new system replaces the old. Then i sit back and enjoy it.
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Re: $680 zoned HVAC instead of $5000 central system

Postby bigmoose » Sat Sep 16, 2017 12:07 pm

Some thoughts as this has been my summer of A/C repair/replacement and large industrial dehumidifier repair.

First, there are some decent R22 replacements that don't have flammable components. R407c is a decent substitute in R22 A/C systems. It needs POE oil however. If you can replace all the mineral oil with POE oil. If you can't one of the manufacturers says to add 20% POE oil over the mineral oil. Research this before you do it however.

For brazing Harris Dyna Flow is a good phosphorus copper rod for brazing copper to copper with no flux. If you need to braze copper to brass or copper to steel you need flux, like Stay-Silv flux from Harris. Cu - 87.9% P - 6.1% Ag - 6% Liquidus 1465 degF Solidus 1190 degF You MUST use a nitrogen or argon purge when brazing or you get nasty, black oxide buildups inside the copper tube that gets circulated to the compressor

That said the industry (most of it) frowns upon Stay Brite #8 8% Silver solder and Stay Clean flux for connections, but I love it and so do many installers. You can solder with Stay Brite #8 with a propane torch, and NO NEED for a nitrogen/argon purge, as it is at a much lower temperature. One of the manufactures support using this silver bearing solder even on the new high pressure R-410a systems.

Key component is to add a good liquid line filter dryer to ALL systems that you open. Emerson EK filter/dryers are a great choice and will neutralize any acid in the system also. I put in all filter/dryers with Stay Brite #8 so that they are easy to replace.

I only braze where I must fill in big gaps. Like when I changed a leaking evaporator on the industrial dehumidifier, I had to braze the capillary tube into a 3/8 inch tubing run. I did the usual squash the 3/8 around the capillary and fill the gaps with braze. The other made up fittings that were male/female I did with Stay Brite #8.

Stay Brite #8 was also used exclusively on a new install of a 5 ton R410a system. Again, follow the manufacturers requirements. Not all will accept Stay Brite #8 if a warranty call is required, and not all building codes allow it.

There you have my summer refrigeration work...

Edit: The new Pepsi Cooler use propane R-290 as the refrigerant, but go look at the service requirements for servicing their cooler. NO removable schrader valve ports are allowed after servicing. All fill lines must be crimped then brazed over. I don't think I want a 5 ton unit running propane in my house. I think my new R410 system has around 10# of refrigerant in it. Would not want 10 lbs of propane vented into my basement.

Edit2: You really need to rethink saving old, old A/C systems. Mine was 28 years old, installed by me back then too. Best I can figure it was around a SEER 8, the new system (one without PWM control of the compressor/fan as we get a lot of lightning strikes out where I am, and appliance electronics let the smoke out quite often) is a SEER 13/14. My electric bill dropped from a typical $480/$520 ish a month to $220 through the heat of the season. Sometimes new pays off quickly... especially if you get the new components at true wholesale.
Last edited by bigmoose on Sat Sep 16, 2017 1:45 pm, edited 2 times in total. View post history.
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Re: $680 zoned HVAC instead of $5000 central system

Postby marty » Sat Sep 16, 2017 4:27 pm

Mr Moose, Sounds like you are the refrigeration guy. I have always been afraid of Freon. Ohio is not too far from Buffalo. Will let you know when something is not getting cold.

I like air. Open the window. Was looking at one of those big commercial HVAC roof top things. Was talking to the HVAC guy. Told him about a cool summer night. Nice weather here. 68° or so? I imagine a commercial building being heated by light bulbs, people, etc. Thermostat calls for AC. What if weather outside is cool enough for cooling? HVAC guy tells me about "enthalpy" Big door on HVAC roof top thing opens to bring outside air in. Honeywell technical guy knows all about enthalpy controllers. Enthalpy control thing measures outside temperature and humidity. With this and a relay I make whole house fan come on instead of AC when it is cool outside. Now we need mechanical windows that open and close automatically.
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Re: $680 zoned HVAC instead of $5000 central system

Postby Matt Gruber » Sat Sep 16, 2017 7:19 pm

Since heating season is fast approaching, i checked the heat on the GE and it is TWICE as good as the Haier :shock:GE has a 14 degree rise vs. only 5-7 for both Haiers.. So my main focus for now, will be installing the GE as a heater, since the Goodman 3 ton really struggles when it drops below 45F and the big duct system has to heat up. Let's see if the GE can do better.it's an unfair test: 36k vs 8k btu, but the GE won't have to heat more than half the house. 2600w vs 715w, so whatever heat it puts out, sure won't cost much. (7 cents per hour)
Added a switch Heat/AC so this ac can be used as a heater. They don't give this option because the coil can ice up. I can get around this by using the attic warmer air. It works like this:
Early AM i turn on heat for up to an hour, then shut it off as the coil may get some ice. The sun comes up and starts to warm the attic. Around 10-11 AM the ice has melted and i get full heat without any more icing, as long as the attic is 52F or higher. Attic gets 10-30 degrees warmer than outside.
.
so here is what i learned from ac experts on how to keep the noise out of the room:
1. must have at least 3 feet between any noise and the register.
2. use a flex duct and make a 90 degree turn. Sound travels in a straight line and gets lost as it can't go around a corner.
3. if the 90 doesn't do it, put the duct in a zig zag box to further dissipate the noise. add sound absorption material as needed.
4. bigger ducts are quieter. sheet metal ducts are noisy. Duct board is better.
5. louvers with wider spacing flow more air and are quieter.
6. Put the ac in a heavy box to block sound. Cover the box with SafeNSound rock wool sound deadener, if necessary. Can put on loft walls too. or any walls that transmit sound. But not in the ac box, as rock wool or fglass fibers can get in your lungs.
7. Any hole in wall transmits sound. Electrical outlets need to be modified to block sound.
8. QuietRock is a special sheetrock that blocks sound 6X better.
.
so you can see, whatever you do, do NOT put a window ac in a wall or a window! 8)
9-17-17 edit
today's tests: took the case off. no sound padding! haier has padding. sounded much better no case, an annoying buzz disappeared, but the db was only down a little 65-68, was 68. the sound was much more tolerable without that buzz.
one expert said that even a card board box could do a lot, so i put the box it came in, on it with the top open. WOW db down to 59-60 :shock: with all the tricks to make it quiet, i may try the box for a test in the loft, and see how it does. maybe i can squeeze in an ac test before winter.
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Re: $680 zoned HVAC instead of $5000 central system

Postby Matt Gruber » Thu Sep 21, 2017 11:15 am

Got this 12"x25' duct from HD:
http://www.homedepot.com/p/Master-Flow- ... W775596449
this thing is huge! i almost fell into it :lol:
excellent to bring in window air direct to the ac. BUT it is taking up too much space. i can't imagine 4 or 5 ac's hooked up in my 10x14 loft. so i may have to use less, but larger ac's or smaller ducts.
Did a heater test hooking the duct to the back of the ac, and 25' later it goes out the window. With 75F air going in, 103F exited! WOW, this could be a good heater! Had 49-50F out the ac side. And there was NO NOISE at the exit;( compressor was 155F after 13 minutes; will watch it when in the loft)
when i stuck my head in the duct, there was just gentle air flow sound.
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Re: $680 zoned HVAC instead of $5000 central system

Postby Drunkskunk » Thu Sep 21, 2017 7:25 pm

If you plan to use these for heating by using the waste heat, you're going to have to modify them. They are designed to sense the temp on the incoming air and shut down when the incoming air on the indoor side is below a certain temp. my Frigidaires shut off at 54º. My Haier shuts off below 61º That keeps the cooling coil from icing up. You'll need to find a way to over ride whatever they use for control so they can operate at much lower temps.


15 years ago my central air broke. faced with a $10,000 repair bill, i went out and bought a
$300 window unit to hold me over until I could sell a kidney to pay for the new AC. It worked so well at cooling the house with just the bedrooms closed off, that i put it off for a month.

and then got the electrical bill.

I had saved more than the cost of that window AC in just one month. So i said screw it, bough another window unit for the bedroom, and never fixed the central AC, enjoying an extra $250 to $300 monthly through AC season for the next 15 years. The original central AC had been a 18,000 btu unit. I had 24,000 BTU of window units. Except for the noise and the less than even cooling, the window units did a far better job.
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Re: $680 zoned HVAC instead of $5000 central system

Postby Matt Gruber » Fri Sep 22, 2017 5:00 am

Drunk
thanks for your comments!
switch is in. it thinks it is 88F in heat mode. also hacked into the control panel for a remote on/off switch.
there are a lot of things to do, that is why i call it a hobby. it costs so little, i can do whatever i want.
How long do your window ac's last?
And if you want to eliminate 90% of the noise and improve the view, put each ac 3 feet from the window, and add supply and return ducts thru the window.
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Re: $680 zoned HVAC instead of $5000 central system

Postby Drunkskunk » Fri Sep 22, 2017 7:42 pm

3 lasted >10 years. i just sold that house and they worked fine at the time of sale. the original one i installed had quit after 5 years. they ran day and night except in the winter.
I have a weekend shack with 2. one new as of 2 years ago that also has a heater, and one i bought used at the same time. it's easily 10 years old and works fine.
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