Install my own HVAC: How hard is it?
Let’s say I have a space in an old warehouse that I use as a clubhouse and a salvaged furnace, a-coil, and condenser. I don’t have much money to spend, but I am experienced enough to rough-in gas and electric, and I can install the copper lines from the a-coil location up through the floor above and up to the roof where the condenser will sit. I’ve seen the crappy work that the jacklegs that my landlord employs and I really don’t see how I, having no experience with ductwork, could screw up any worse than they do.
Could someone walk me through the steps it takes to install?
I would assume:
1. Set furnace (this will be 8′-0″ off the floor (above a kitchen space)), and I have 14′-0″ ceilings.
2. Set a-coil.
3. Set condenser.
4. Run supply and return copper lines from a-coil to condenser.
5. Rough in electrical to furnace and to condenser.
6. Install return air ductwork
7. Install supply air ductwork
8. Install thermostat and wiring
9. Drain line for a-coil drip
Assuming I could do all of that, then I could have another AC guy (another guy I know, who is also a jackleg, but not as bad) come in and finalize the connections and charge the system, right?
I know that HVAC is complicated, but its not rocket science, and the crackhead that my landlord wants to use can barely add, so I figure I can do better myself.
Anyone want to give me a rough and dirty method of calc’ing required duct sizes? How much furnace BTUs do I need, how much AC capacity?
The space is basically square in plan, 1,200 square feet in area, with 13′ ceilings. My maximum occupancy is about 80 people.
Landlord has most of the equipment and ductwork. This guy wants $500-600 for labor to install everything (I have to buy any additional parts). Doesn’t seem like a bad price to me, but in the end there’s no guarantee anything will actually work.
I’m not trying to get the climate perfect, I’m just trying to take the edge off the heat and a bit of the humidity out of the air.
Any advice?
Replies
These guys might be of help. Never used them, but getting the design done (sized) correctly is 1/2 the battle.
http://images.google.com/imgres?imgurl=http://www.aircomfortdesigns.com/doityourself/graphics/example.jpg&imgrefurl=http://www.aircomfortdesigns.com/doityourself/index.html&h=324&w=500&sz=68&hl=en&start=5&um=1&tbnid=YGArFeX9wJ9vFM:&tbnh=84&tbnw=130&prev=/images%3Fq%3Dhot%2Bwater%2Bbaseboard%2Binstall%26um%3D1%26hl%3Den%26sa%3DN
Got silphos and acytelene torch? N2 tank? Otherwise, dont try the copper pipe for AC, but every thing else is easy.
Google 'duct sizing' and you will get some calc worksheets. If the landlord has all the ducting available and it is for rentals, just guess at the sizes based on what you have seen in the past.
So your're going to scab in some gas lines and shoddy electrical invite 80 people over for a party...Hmmm sounds like a liability case.
It's not rocket science you should be able to find some online calcs for the duct work, just make sure the gas and electrical are up to code.
Dude, my work is good. I've done plenty of electrical and plumbing and have passed inspections before. I'm not worried about the quality of MY work. I'm worried about the quality of crackhead's work.
it's not rocket science and it's not hard to do ,all of it.BUT that said i have to say you have to think of this as a commercial setting with 80 people in it. if something did go wrong you would never own another thing in your life.i know the chances of something happening is so slight,but if you move next year and the next tennant turns the gas on and blows his #### up,your the one the will talk to.
landlord has a guy that will do it for 500? tell the landlord to geter done and pay him the 500. if something happens it's his building and his worker that did it.to tell you the truth if you did this in one of my buildings,i'd turn it in to the inspectors,and let them red tag ya.i don't want to own your problems.
if you insist on doing it,read all you can on the specific codes and over do it.
here is an example of what could happen this was 2 days ago ,what if the tennant wired up a clg light and this proves out to be the cause. u owe 4 million bucks.plus another 1mil for lawyers. http://www.kake.com/home/headlines/19472404.html
risk and reward, larry
if a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
Well your story on the strip mall doesn't list any cause of the fire. It could have been started by a lit cigarette in the pile of dry cleaning clothes. But yes something similar could happen.
that story was the night of the fire,they still don't have a cause,looks like something in the ceiling started it,they just haven't found it yet. thats why the reference to a light was made. larryif a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
"Doesn't seem like a bad price to me, but in the end there's no guarantee anything will actually work."
That's the $6400, "will it work?" question. IMO single-room, mini-splits are definitely DIY projects for anyone with good skills. When you get to a whole-house system with brazed lines and ductwork the cost of gotchas and screw-ups can be pretty high.
Advice?
Let someone else handle it.
If it was important, you wouldn't be thinking about utilizing leftover junk OR hiring a hack to do the work. If it was important, you would have had it professionally done before this "gift" was offered. Given your criteria, Mr Crack can suffice.
Jeesh... So many haters. Believe me, if you could see the space that my "landlord" (building owner) and other friends put together for spare time, salvaged materials, and about $5000, then maybe y'all wouldn't misunderstand the reasonable-ness of my request.Well, I guess my request for information doesn't really fall under the rubric of "Fine Homebuilding" anyway...Hypothetical Question:
If I was going to attempt to educate myself a little better about HVAC system design, anybody have any website recommendations.
if you just want it for cooling you don't have to mess with the gas at all.
any idiot should be able to run the electrical line, thats what the apprentices do on jobsites after they have mastered drilling holes. have it inspected, and connected by your friend who is somewhat less of a jackleg than you, if he charges AC systems he should be able to handle that.
i agree you should be able to "set" the individual components, and do the labor work of getting the elec line close, and even tie it in if you are confident. be sure you are correct, ask questions, have it looked at.
were not haters ,were just trying to help you cover you but.
as far as instructions go,i'm not sure you need any.set it, the furnace will have clearance specs right on the data plate along with the wiring. 3 wires 110v circut,2 24v wires go to the condenser,and 4-6 wires to a thermastat. it's wired.hook the flue up and if your in enclosed space you will need two make up air ducts .run the gas line ,test it with a soap solution
set the a coil box on top/bottom depending on flow,go out set the condensor,run a 220 volt to it with the right amps,again it's right on the air usally 30-50 amp,hook up the 2,24v wires,run your lines.
now if you want to hire it done from here fine. if not put in a filter on the low pressure side,get some silver solder and solder it. turn the valves on for freon[it should be pre charged] and 9 times out of ten it will be good for the next 12-20 years,just about the same ratio as if you hire it done.
whats the worst that can happen? it won't work or you burn down the building,then you get a new building. no problem. larryif a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
Pardon my initial response. Seemed like a exercise in futility, But if you really want to do this, don't say you weren't warned...
To answer a few of your questions, there are some basic estimating numbers you can use to approximate the necessary capacities of heating and cooling equipment.
One is to estimate cooling loads (in a large portion of the lower 48, assuming some reasonable level of post war construction) at 1000 btuh (that's btu/hr) per person. This accounts for ventilation and assorted other loads related to an occupancy that is primarily for people gathering. This is on the upper end of the range for sparsley populated spaces.
For duct sizing, find what is called a "ductulator" and select ducts at 0.08" of static pressure loss for supplies and 0.05"/100' for returns. You should be able to find a ductulator from most any supply company.
Heating can be estimated by square footage as well. A well insulated home in southern regions of the country could get away with less than 10 btuh/sq.ft. An older, poorly insulated buillding in the upper midwest will require over 50 btuh/sq.ft. to maintain a reasonable level of comfort. What part of the country and what kind of contruction?
Running and connecting the line set shouldn't be too difficult. Though many will disagree, plumbing solder can be used, silver based solder being better, and as JH mentioned, Sil-Phos rod with the propoer flux and a brazing torch is the best way to assemble refrigerant piping components.
A single website? ASHRAE is a place to start. Highly engineering related, though. There are HVAC forums (fora?) out ther that probably have much more practical and simplistic discussions.
hell yes you can.... and you know you can...
you know i never ever question junkhound... but i have seen 100's of refrigeration copper lines done with a regular plumbing b torch... not the way i'd do it... but seen it done alot and it worked... watched guys never pull a vac on the lines... and it worked... seen #### all in the lines and guys just left it... and it worked... I've watched guys without gauges charge systems just by feeling the lines... and it worked...
if you knew zero... I'd still tell you that you could do it... if you can read you can pretty much do anything... i rebuilt an automatic transmission when i was 16 with just a book from the public library and a then $40 kit....
I'm always amazed at all the people who will look for 1000 reasons why someone else shouldn't do something... when all they are really say'n is... "I wouldn't try that" like you are smart enough to assess all the risks and make up your own mine... surprised no one told you to hire an engineer to design your "system" or it'd never work...
good luck
p
well put, I think i found my long lost twin :)
but seen it done alot and it worked
seen lots of stuff work but not very well <G> -- reason I have strong opinion against Pb-Sn for reefer lines is that the first system I did (circa 1970) I'd just 'slobbered' them up.....
Started leaking about 1-1/2 years later.
dude you know i never question you... there should be a statue of you being "green" before anyone had a clue what green is... not that they do now...
doing what you can with what you have is what builds character and how we all learn... my FIL rest his soul installed some of the first home a/c units in this area... had vac pumps built out of old refrigeration compressors and used the same tools to run plumbing that he used for refrigeration... and this man worked building nucular power plants....
if someone is going to ask... then yes I'll tell them the best that i know...
i grew up in a home where i was never told i couldn't do anything so i guess i just never learned....
peace
p
i grew up in a home where i was never told i couldn't do anything so i guess i just never learned....
Best kind of home!
I swear this is not tongue in cheek: if you read the instructions that come with the units, furnace, a-coil, condenser, thermostat, etc, it will pretty much get you there. There are definitely caveots while running ductwork, or bending sheet metal, or figuring out the easy way to do something, but i've done it twice now and it IS actually getting easier -- I remember saying the in the beginning: "I ain't no sheet metal guy." I'm getting pretty good though. Get yourself some good UL tape and go for it.
The only thing I would NOT recommend DIY is the line set. I would let someone else braze your line set and install the refrigerant. You might run them from furnace to condenser, and just pay someone to connect and test the system. I have a friend who "installed" my HVAC, which included purchasing the equipment (which requires a license here), running line sets, exhaust (90% horiz. pvc) and electrical hookup (which i could've done but didn't want to). I ran all the ductwork, set the units and taped everything off. it's amazing what sheet metal screws, a home-made brake and some UL tape can do : ) (See pics)
As for design, I have a tool called the "Ductilator" that helps you size your ductwork. I did a rough draft and my HVAC contractor gave it to a "professional" who double checked it. Yes, things changed, but what I came up with would've worked just fine -- in fact it was a little bit bigger than what I ended up with, so i guess you could say I overengineered it slightly. It helps though to have a pro tell you how much heating and cooling BTUs you need.
Good luck.
You require an inspection?
gasline and electrical probably wouldn't pass.
gasline
iz dat wut dat yeller hose iZ???
yup. saw a picture of flex hooked to the ac drain. they wondered why the gas was leaking.
Strangely not for GAS. My plumber did that, btw. And the electrician and HVAC contractor put the electric in, rough and finish respectively. Everything passed fine on the other inspections. Got anything else you wanna be picky about. Are my joists crooked. Is the filter slightly out of plumb? haha, just kidding. These photos are likely from 3 months ago prior to having it all tied up and "finished," so I wouldn't get too picky on them.
Those strange trapezoidal transitions were made with one piece, btw. BAM! (Well, 2 of the 4 -- what a pain!)"It depends on the situation..."
Not being picky, just questioning inspections. Trust me, it's easy to be picky.
It's ok. A lot of folks on this forum ARE, which is ok once you figure that out. Be strong OP!"It depends on the situation..."
Oh good you have a salvaged furnace, good for you, has any one pointed out to you a thing called CO which can come from a cracked heat exchanger. Most cracks will not show up till the the furnace is installed and fired or after several cycles. Using a salvaged furnace is not a good idea, unless you know that it is only a few years old, and was salvaged for a good reason. 1000 square foot added to a house the furnace was three years old and needed up sizing and it was your Dads. You might wind up with 80 friends in the Emergency room. 80x1000 = 80,000 not including the few that could end up in ICU at 10,000 a night. Does your club have insurance, is it incorporated, might want to look into that first, just in case someone slips on a wet floor.
What type of lease do you have with this landlord that makes you take on the burden of the HVAC?
Why doesn't each of your "Club Members" kick in a 100 bucks and hire a proper installer to do it right, if the lease spells out that the HVAC falls to you? That would be 8000.
I get the feeling this arrangement is very informal, you are on a month to month if at that. So you go put this in and next month you get the boot.
Your profile is not filled out so I have a feeling you are on the younger side of life, and my warnings as those of others are falling on deaf ears.
Wallyo
You could get a CO detector, that is if while the thing is going off during a party one of you club members does not rip it out of the wall and yank the battery out. By the BY do you even have several working smoke detectors? If not go spend 50 and buy some today.
Edited 6/11/2008 11:23 am ET by wallyo
Whew! OK, grampa, we'll careful.Now, back to the topic at hand: Anyone got a good source for an online Ductulator?
Edited 6/11/2008 11:27 am by rasher
Rasher I am not that old, from your response I take it that you are a young pup and I have fallen on deaf ears. So how about a bit of maturity and answering or addressing a few of my points. Never mind I am just wasting my time with you and have better thing to do with my life.Wallyo