$680 zoned HVAC instead of $5000 central system

Talk about anything and everything here within reason.
Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

$680 zoned HVAC instead of $5000 central system

Post by Matt Gruber » Aug 31, 2017 5:43 am

I'm giving a thumbs down to a new R410a replacement heat pump/ac due to numerous reports of problems with r410a TXV expansion valves etc, AND i figured a better way to do it for 80-90% less.
My 10 year old R22 system(3 ton cost $2850) is obsolete due to AC guys charging $65/lb. to fix it. It holds 12 lbs, do the math! and r22 will no longer be made after 2020, not to mention it is bad for the ozone layer.
.
So i designed my own system, to be installed by me in my attic loft.
Goals :
1. no more calls for service ever. must be easy and cheap to fix myself without gauges or ac training.
1B. No more complete ac failure, as long as there is power, some rooms will always have ac. Any failure is limited to 1 room. This is a goal, as lightning can do a lot of damage.
2. individually zoned rooms, don't cool/heat rooms unoccupied. plan to use up to 50' of 8" R6 duct ($66), and 10-11 registers, $60.
3. Must work as heat pump, not just AC.
4. Nothing in windows or outside walls, too noisey .
5. Nothing outside, so less rusting from salt air, and no rain hits system.
.
So now i'm making a 46"x16" louver with fan for the 3x4 attic window. Have an 800 cfm 12v Spal fan, as plenty of airflow will be needed, as heat pumps and ac work by transfering the heat from/to the air. in addition to the fan, there is a 28' ridge vent and soffit vents.
Last edited by Matt Gruber on Sep 05, 2017 3:50 am, edited 10 times in total.

User avatar
skeetab5780
1 MW
1 MW
Posts: 1839
Joined: Jun 15, 2009 10:58 pm
Location: MA
Contact:

Re: $780 zoned HVAC instead of $5000 central system

Post by skeetab5780 » Aug 31, 2017 6:30 am

Wheres the punch line? I dont get it your replacing a heating/cooling system with a fan?

Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

Re: $780 zoned HVAC instead of $5000 central system

Post by Matt Gruber » Aug 31, 2017 6:52 am

skeetab5780 wrote:Wheres the punch line? I dont get it your replacing a heating/cooling system with a fan?
:lol: No, the spal fan cost $12. the $780 includes 25,000 btu cool(5000btu x 5) and, i'm not sure how much heat it will make as a heat pump, but it should be half the cost of resistance heat, or better.
Thanks for the quick reply!
I guess the punch line is:
treat ac like any appliance. you would not call for service on a toaster or mwave oven, right?
You just buy a new one as needed.
with 5 or 6 small ac, you just buy a new one as needed. they only cost about $99-139each.

Hillhater
100 GW
100 GW
Posts: 8332
Joined: Aug 03, 2010 10:33 pm
Location: Sydney ..(Hilly part !) .. Australia/ Down under !

Re: $780 zoned HVAC instead of $5000 central system

Post by Hillhater » Aug 31, 2017 4:55 pm

A little more detail/explanation would be appreciated... (says owner of ageing ducted system !)
You are going to replace a single large centralised system with 5 individual AC units...all in one location the roof space, and run ducting to the rooms ??.....
..What is the cost. (<$100 ?) of these units (brand, spec ?)
Thanks
This forum owes its existence to Justin of ebikes.ca

Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

Re: $780 zoned HVAC instead of $5000 central system

Post by Matt Gruber » Aug 31, 2017 5:23 pm

Hill
i got one of these for a test from jet.com (they give a 15% discount on 1st order)
free ship, $89 total. :mrgreen:
noise is my main concern, if is too loud, Frigidaire FFRA0511R1 gets great reviews, 94% would recommend, $129 at best buy 135 home depot. The Haier gets :D 84%, so the question is, will i hear a difference? If so, than it is well worth the extra money.
https://www.walmart.com/ip/Haier-5-000- ... D/49368526
.
and i'm not replacing the old system until it fails; this is independent and redundant.

Hillhater
100 GW
100 GW
Posts: 8332
Joined: Aug 03, 2010 10:33 pm
Location: Sydney ..(Hilly part !) .. Australia/ Down under !

Re: $780 zoned HVAC instead of $5000 central system

Post by Hillhater » Aug 31, 2017 6:06 pm

Thanks,...$89 :shock: ... much better deals on your side of the pacific !
Wont having to " duct" them into the room reduce the output/ efficiency a fair bit ?
Why dont AC adds ever list the power draw on those units ?
This forum owes its existence to Justin of ebikes.ca

User avatar
Chalo
100 GW
100 GW
Posts: 6122
Joined: Apr 29, 2009 11:29 pm
Location: Austin, Texas

Re: $780 zoned HVAC instead of $5000 central system

Post by Chalo » Aug 31, 2017 7:49 pm

Hillhater wrote:Why dont AC adds ever list the power draw on those units ?
They seem to get better every time I buy one. The last 5500 or 6000 BTU window units I got (some years ago) were rated under 10A maximum.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

User avatar
spinningmagnets
100 GW
100 GW
Posts: 10721
Joined: Dec 21, 2007 10:27 pm
Location: Ft Riley, NE Kansas

Re: $780 zoned HVAC instead of $5000 central system

Post by spinningmagnets » Aug 31, 2017 7:55 pm

My adventures in home cooling:

When young and poor, the AC bill in the summer was oppressive, so I looked for ways to lower the bill. I had been up in the attic a few times for various reasons, and it was incredibly hot, in spite of there being several vents around the edge. I saw an ad for attic fans, and bought a small $60 unit that had an integral temp sensor that was settable. It would kick on when it was hot, and automatically go off when it cooled off in the evening. I also rigged it so it could be set to always off or always on.

Not only did the attic have several vents around the edge, each end had a roughly one-foot square vent (standard rectangular starter home). The fan was mounted over one of the large square end vents. When the attic reached a certain temperature, it kicked on. You could also lock it in the on position, and then plug it into a timer. Doing that allows the attic to stay warm in the first half of the evening (to conserve electricity), but still kicks on in the part of the morning when it starts to get hot.

When on, it used the watts of a light bulb, not bad at all. It could run all day, even when the AC was on, if desired. The attic and the occupied part of the home were kept separate. It paid for itself in the first month of operation. They are probably $100 now.

xxxxxxxxxxxxxxxxx

After that, I went into the attic for some reason in the summer, and the occupied 3/4ths of the home was reasonably cool (that was the side that the fan was on), but I was surprised that the other end (over the garage) was not getting much circulation, and was still hot. Apparently air was coming in from the small vents along the sides of the attic and being blown out the large end vent with the fan.

I considered getting a second fan for that end of the attic, but didn't know if setting it to push or suck would be better. While pondering this, I came across a "whole house fan". It is a large low-RPM fan that in mounted in the ceiling of a centrally-located hallway. When it kicks on, it pulls air from every door and window gap, and pushes it up into the attic, where it flows evenly out every available vent. Outside air is pulled into the living space. It was $140 at the time. For obvious reasons, it should not be run at the same time as the air-conditioner.

It had a screen and also gravity-pulled slats, which lifted up in the airflow when the fan was on. When flow was off, the vent-slats lay flat to block tiny insects from passing from the attic to the living space.

It significantly reduced the number of hours that the AC had to run to keep the home cool. And it significantly reduced the number of days where the AC ran at all. If you set it to run for a couple of hours (on a timer) in the early summer morning (4-AM to 6?), the cool air would cool off all the thermal mass inside the house before the sun rose.

It used the power of a 100W bulb, well worth it. I also acquired a small window AC unit, which I put on the master bedroom window in the summer. That way, on the hottest days, I could cool the bedroom alone, instead of the entire house.

xxxxxxxxxxxxxxx

On the side of the house that faced the afternoon sun, I hung some coarse plastic gardening sunblock cloth from the eave edge with a staple-gun (my eaves extended about a foot over the edge of the outer walls). It shaded the outside of the walls and the windows. I did this after I had noticed that...even though pulling the curtains closed on the inside kept a room cooler than before, I could feel that the glass of the window was VERY hot, and it would be best to shade the outside. Cost maybe $20, put them up in the summer, fold up and put in the garage every fall, winter, spring...

Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

Re: $780 zoned HVAC instead of $5000 central system

Post by Matt Gruber » Sep 01, 2017 4:22 am

Hillhater wrote:Thanks,...$89 :shock: ... much better deals on your side of the pacific !
Wont having to " duct" them into the room reduce the output/ efficiency a fair bit ?
Why dont AC adds ever list the power draw on those units ?
i don't even know where jet is located! it is owned by walmart.
the 8" duct is rated for 200 cfm. the ac is 135 cfm on high. so i don't expect much loss, going thru 3-6' of duct. the 6" duct is rated 100cfm and should be avoided imo.
only 1 room gets a long duct, 12', and i'm running it inside the room, not the attic.
the haier is rated 3.9a, 445w. my meter said 471w at 123vac after 1/2 hour. it is better than my 15 yr old haier, 520w.

Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

Re: $780 zoned HVAC instead of $5000 central system

Post by Matt Gruber » Sep 01, 2017 4:38 am

spinning
thanks for your reply!
i do have a whole house fan, 40w, 30" for both heating and cooling, but it is too hot and humid to use it much in the summer. works great when it gets down to the 60's at night. now it is 75-81 :roll:
the fan is an ordinary ceiling fan that cost $20 18 yrs ago. it reverses and brings down warm attic air in the winter.
heat pump mode should work well with my new ac system, i won't have to wait until the afternoon anymore for cheap/free heat. it would take all day for the attic to reach 85 on a 60's day. i will duct to attic peak into the ac, but, backwards for heat.

User avatar
dogman dan
100 GW
100 GW
Posts: 34308
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: $780 zoned HVAC instead of $5000 central system

Post by dogman dan » Sep 01, 2017 6:06 am

I took a simpler approach, since to start with I have the evaporative cooler on the roof. First thing, doubled the attic insulation. That did more to keep the house cooling and heating bills down than anything I could have done. Now no need to cool the attic, really. Cost was 200 bucks then, now more like 400. This also buried all my duct really nice, which made a huge difference year round.

Then I just put some window type coolers in three locations. But not in the window, under the window, in a hole I cut in the wall. Much like a motel room. One 1200 btu, two 8000 btu. 5000 won't do shit in this climate. I use the old cooler sometimes, but mostly just cool the room I'm in at the moment with the individual AC's.

People say they are too noisy,, and they do make some noise in the room. The house I'm renting now has central AC, and it's a whole lot noisier than the window units when its running. :roll: But this is mostly because of the type of roof this house has, no attic, and the compressor shakes the whole hose. :lol:

your plan will result in poor performance of the coolers, since the attic will be hotter than outside, unless your fan is gigantic. The condensers will work inefficiently. It would be possible to duct some outside air to them I suppose, but the outside part of those AC's really needs to be outside. On a really hot dry day, give them a sprinkle of water to get the cold really cranking out of one that is working poorly.

You will also need to catch and drain off the condensate they make when it's humid.

Maybe you can build it so they are located in a small hut outside the actual attic? or are installed in the gable end of a roof?

Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

Re: $780 zoned HVAC instead of $5000 central system

Post by Matt Gruber » Sep 01, 2017 8:19 am

Hi dogman,
how do you define attic?
my loft is a 10x 14 area at the gable end of the "attic", with a 3x4 window and a 30" x30" automatic vent if needed. the ac units will think they are outside in a non-ocean area. it only gets to 86 on average, with a peak this year of 92 and many nice 84 days.. when it is 90 and full sun, the loft is 104-110 4pm, window and vent CLOSED tight! many areas get to 104-110 every day and the ac runs fine. they don't get to open a window like i do. But you make good points to anyone with a 130F attic that reads about this, and thinks they can add 5-10 ac's with no added airflow. Also keep in mind any efficiency loss will be reversed in winter, when the ac's are reversed and make heat. That is the plan that needs to be tested, as i am a skeptic too. i need proof, and over the next year i will collect data. if it doesn't cut the mustard, it will still be a good emergency ac system for when the main system needs repair. It is a fun hobby, i love experiments!
.
i collect my ac water in a 5gal bucket and water the shrubs. my new units will plumb into the existing drain. i get 3-5 gal almost every summer day!

markz
10 GW
10 GW
Posts: 4741
Joined: Jan 09, 2014 11:38 pm
Location: Alberta Canada

Re: $780 zoned HVAC instead of $5000 central system

Post by markz » Sep 01, 2017 7:28 pm

I see your dilemma. Perhaps best to refill the current ac system with r22 and try to find someone cheaper to do do the job.

Factor in how long that r22 will last before you got to scrap it beyond 2020.
Then in the meantime, find the best deals you can for window ac units, whether they are used or new. Best to go new, but find a liquidator like the guy on TV in Vancouver, https://www.directliquidation.ca/
Because I am sure if you can find units at Walmart for $85, then that guy ^^^ would be like $45 if you buy 5.



https://refrigeranthq.com/much-r-22-ref ... ound-2017/
R-22 Refrigerant Price Per Pound 2017

Ok, so you’ve got an R-22 unit that needs a refill. The rule of thumb that I like to use when checking prices is rather easy. I simply go to Amazon and E-Bay and physically check the price of the refrigerant there. These prices are more or less in line with each other. There may be a few outliers here and there but for the most part they should average out to about the same price. As I write this article in mid December 2016 the price on Amazon and E-Bay on R-22 is between $500-$650 for a thirty pound cylinder.

dustNbone
100 W
100 W
Posts: 294
Joined: Mar 13, 2016 9:59 pm
Location: Vancouver, BC

Re: $780 zoned HVAC instead of $5000 central system

Post by dustNbone » Sep 01, 2017 8:09 pm

Refrigerant gas isn't supposed to be a consumable. If the unit is short on gas, it's because there's a leak in the system. At least here it's illegal to recharge a system until you've discovered and repaired the leaks, and had the system pass a vacuum test. I've serviced heat pumps that ran for 20+ years with no measurable leakage at all, all the maintenance they need is cleaning the coils once a year, changing the filter in the inside air handler, nothing expensive. They might kill a condenser fan every 10 years or so.

The biggest drawback of the cheaper smaller self contained units is efficiency, and long term reliability. They will never work for 20 years without major failure, that's just not going to happen. Consider yourself lucky if you get 5 years. And over that time you'll probably pay back every penny you saved in additional energy usage (vs a properly functioning external heat pump).

User avatar
nutnspecial
1.21 GW
1.21 GW
Posts: 3794
Joined: Mar 03, 2015 10:19 pm
Location: PA

Re: $780 zoned HVAC instead of $5000 central system

Post by nutnspecial » Sep 01, 2017 9:10 pm

Arrow up. Yup. And the whole thread is intersting. the one MF thing I can't do is the cooling side of hvac around here due to regulations requiring cert for freon etc.
But I can put it in my car, fridge or window unit :?

The thing I have to add is overall converse to the thread nature/direction. I do NOT use 'living space' AC unless it's once or twice, or maybe driving in a car that has it. The indigents didn't use it- they didn't have it. Perhaps I'm slanted cuz I'm on the skinnier side, or perhaps people would be skinnier if they survived like the indigents for their area. Or just plain healthier- so I'm not trying to say that 'skinny' is necessarily indicative of that.
Surviving the 100+ f index summers here isn't hard with even a basic non-ac above ground structure imo, and I'm challenging myself to a basic 50-55d f heating for 'home' in the winters. I aim at balance with nature, which leads to better health imo?
And as a sidenote, even if you 'go' (read: die. Which I defy anyone to accurately describe past 'death' lol) at an early/young age I think it's all ok and maybe you were better off overall, quite possibly. Just a different perspective from what I've mostly read.

dustNbone
100 W
100 W
Posts: 294
Joined: Mar 13, 2016 9:59 pm
Location: Vancouver, BC

Re: $780 zoned HVAC instead of $5000 central system

Post by dustNbone » Sep 01, 2017 11:06 pm

No way man. Dying is bullshit, I avoid it as much as possible.

Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

Re: $780 zoned HVAC instead of $5000 central system

Post by Matt Gruber » Sep 02, 2017 5:56 am

good comments!
i was just giving 1 example, citing r22 cost. in FL anything outside rusts out in 10 years. so while i got 17 yrs from the previous unit, even the air handler was like swiss cheeze by then.
the aluminium fins mostly fell off, impairing efficiency. the evap. coil leaked and it was gone. the accumulator rusted out after 7 years, at that time r22 was $6/lb and it cost 165 to fix. now more like $800.
the new higher eer use thin copper to boost btu's, and the copper work hardens and cracks and leaks sometimes within 1 -2 years :roll: Goodman had a recall on some. r410a requires much higher pressure than r22, and requires ~25% MORE energy to compress, so this is why they require higher eer, to make up for the increased energy use. so the new high eer are thin JUNK that won't last! This is why i am now avoiding them. My 15 year old Hair window unit could last another 15 years inside as it is only 9.7 eer and while considered cheap at that time, it is now superior quality!

User avatar
dogman dan
100 GW
100 GW
Posts: 34308
Joined: May 17, 2008 12:53 pm
Location: Las Cruces New Mexico USA

Re: $780 zoned HVAC instead of $5000 central system

Post by dogman dan » Sep 02, 2017 6:23 am

I get it,, your attic/loft does not reach 140F like they do here. I just assumed if cooling was a problem, your attic, even with a blower vent, would be in the well above 110f range.

You'll still have to catch the condensate, but that should not be hard. just need a tube on the drains from the pan. And it cant be small enough to clog.

User avatar
nutnspecial
1.21 GW
1.21 GW
Posts: 3794
Joined: Mar 03, 2015 10:19 pm
Location: PA

Re: $780 zoned HVAC instead of $5000 central system

Post by nutnspecial » Sep 02, 2017 6:32 am

Very interesting Matt- very good points, it sounds like you're on to something with this. I only recently started learning how to identify coolants and fix fridge and auto units. The fridge I fixed was an awesome deal for an awesome newer sidebyside in immaculate condition, and just needed a section of line replaced on one side, and a recharge.
The theory behind heatpumps, ac, fridges, etc is so simple though, just like an aircompressor how pressure relates to heat (or the lack thereof). It's so interesting how one might try to further relate pressure and/or heat to light and sound too.
Matt, I'm assuming these newer minispits are very high eer and would not be as reliable in the long run? I do like how much lower of temps they can be efficient though! I wonder if they're more efficient on the other end of the temp scale as well?

Items high on my list in that category:
Get and learn brazing tools and technique.
Make an air compressor from a fridge compressor.
Also, make a genny head from a washing machine motor, but that's not hvac.
Oh, and figure out the best heating (and possibly cooling) system for a large (15000 cubic ft) and a small area ~100 cubic ft, especially if natural gas isn't readily available (or invest in a gas well? hahah). Latest thought was outdoor wood fired hydronic, mixed with solar passive, mixed with active solar hydronic.
I avoid it as much as possible
Well yes of course dustNbone lol! I was just thinking freely (and aloud) to deeper conclusion, after veering into modern Hvac and the rather intangible/indirect theory of how it could pertain to basic overall population 'wellness'. Btw, 'indigent' was somewhat accurate (had to look it up), but I kinda meant more 'indigenous' I guess.

Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

Re: $780 zoned HVAC instead of $5000 central system

Post by Matt Gruber » Sep 02, 2017 9:14 am

nutspecial,
thanks for you input!
here is a video, explains why brazing isn't good in the field:
much better to solder! but only with very hi-temp solder
https://www.youtube.com/watch?v=wJD712DB6S0
.
i like the mini-splits, especially the Pioneer with the lower seer, 17
$790 for 18,000btu inc free ship! see highseer.com
take an extra 10% off with code PDSPC
https://www.highseer.com/high-seer-inve ... 18-17.html
BUT they don't recommend them near the ocean, the PAM inverters can't take the salt air! they should know, they are in Miami. So i had to skip this very good idea.
In PA, consider the condenser in the basement. this should be even better than an attic. You get geothermal transfer to the air. Be sure to insulate the floor, or it will suck energy from the room above.
Last edited by Matt Gruber on Sep 02, 2017 2:09 pm, edited 5 times in total.

Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

Re: $780 zoned HVAC instead of $5000 central system

Post by Matt Gruber » Sep 02, 2017 11:08 am

dogman dan wrote:I get it,, your attic/loft does not reach 140F like they do here. I just assumed if cooling was a problem, your attic, even with a blower vent, would be in the well above 110f range.

You'll still have to catch the condensate, but that should not be hard. just need a tube on the drains from the pan. And it cant be small enough to clog.
had to plug 5 holes on the 15 yr old Haier, and added 2 drains, one on each side, each tube has 6 holes in it, so it should not clog for a long time.
the new Haier has no holes, as the water is used for cooling the coil. so easier to add drain.
these ac's will be on the loft floor, and will be very easy to check frequently, and i expect to see rusty water eventually(clear tubing). At that time, i'll give them a sand/repaint.
.
i plan to place each ac on 4-6" of mattress foam, so they don't transmit noise.

Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

Re: $780 zoned HVAC instead of $5000 central system

Post by Matt Gruber » Sep 03, 2017 9:13 am

:shock: had the case off the 15 yr old haier, and made an surprising discovery!
the cold air blows UP 46", on Low, with 2 or 3 times the force(volume) as with the case on, and blowing straight out.. The fan does not like making a 180 degree turn, and it will be much happier making just the 90, once i cut off the top 6" of the case. :shock: there was no change in noise either way. It still has to make another 90 to get into my room, so i'm prepared to try different adapters to keep the air flow up. Plan to make from cardboard, quick to cut for tests.
reminds me of a review a lady gave of the Frigidaire that she returned. she said it was quiet on low but would not cool the room. It cooled the room on Hi, but was too noisey so she returned it.
Speaking of noise, i also did a db test today,
the new haier was 57db on low on the floor of my garage. i closed the door to my shop, and it dropped to 47.3 db. :shock: so, this confirms why all quiet systems have the compressor behind a wall, and explains why i am not going to put it IN a wall, it must be BEHIND a wall to be quiet.
And the WORST place to put a window ac, if you want peace and quiet, is in a window :roll: :lol:

Matt Gruber
100 kW
100 kW
Posts: 1343
Joined: Feb 08, 2007 11:02 am
Location: New Smyrna Beach FL

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

Post by Matt Gruber » Sep 06, 2017 7:51 am

Here is a great example of what can go wrong with an indoor ac:
https://www.youtube.com/watch?v=upZWfOh6bJg
should anyone think this is easy, think again!
kudos to this guy for getting it working on the 2nd try.

User avatar
Chalo
100 GW
100 GW
Posts: 6122
Joined: Apr 29, 2009 11:29 pm
Location: Austin, Texas

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

Post by Chalo » Sep 06, 2017 4:34 pm

Matt Gruber wrote:Here is a great example of what can go wrong with an indoor ac:
https://www.youtube.com/watch?v=upZWfOh6bJg
should anyone think this is easy, think again!
kudos to this guy for getting it working on the 2nd try.
Wow, that's really dumb.

If for some reason I felt I had to do that, I'd use a squirrel cage blower with an exhaust duct, plus a water mister on the hot coils, all on a thermostatic switch.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

User avatar
spinningmagnets
100 GW
100 GW
Posts: 10721
Joined: Dec 21, 2007 10:27 pm
Location: Ft Riley, NE Kansas

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

Post by spinningmagnets » Sep 06, 2017 4:47 pm

Get and learn brazing tools and technique
Acquiring new tools and skills are always a good thing. However...for copper pipe bonding, consider resistance soldering. A common DIY "spot welding" MOT from a 1500W microwave oven puts out 3V and over 400A. Two probes contact the pipe on either side, and a foot-switch controls the on/off.

It will rapidly and easily heat the joint to brazing temps. You can also swap-out the secondary winding (welding cable) to get 2V and 600A.

Post Reply