I get by with help from my friends.

ChrisJ

Hi all.

As you may remember, I got it in my head that I had enough of window shakers back in August of 2016 and decided it was time to do something about it. Since then, I've been doing my best to learn, and understand forced air systems as well as design one for my home with help from others.

Unfortunately, my arthritis has been really bad making this a slow and painful process, but things are getting done so I'm happy about that.

None of the actual work has been that easy and my wife wants to kill me as our livingroom has been full of duct work for quite a while now, but it's slowly making it's way into the attic finally. Just like with the steam boiler anyone that feels HVAC guys make too much money should try doing this themselves. It's not easy and a lot of it is not fun. I cannot imagine trying to do it under the gun to get it done fast.


The initial duct lay out as well as an awful lot of help has come from Bradford White. A few guys from the Wall have helped out as well with tweaks, ideas etc as well as helping out with doing a proper heat gain which took quite a while. I don't want to mention names in case these people do not wish to be known. I appreciate all of the time they put into helping.

@njtommy was nice enough to help out with supplying the equipment which came from a proper distributor. He did this, even though he loves mini-splits and felt I should be doing a mini-split system.

@Bob Bona did the Manual J and has spent hours and hours helping out with things.

My custom made supply and return plenums as well as a 14x30 ceiling box came from a really close friend of mine that runs a metal shop. They are not made like traditional ductwork, but he did his best using 20 gauge galvanized steel.

All joints are sealed using silicone and or UL listed "rolled mastic" tape. So far, most of it has been silicone on the inside, with the tape on the outside.

All insulation is R8 fiberglass.

There are two 14" round trunks which feed short (5 foot or less) runs of 9" and 8" flex as well as two 10" hard pipe runs to the first floor. The air handler is isolated via flex connectors as well as vibration isolators and will hang from the rafters.

This is a 2 stage 3 ton system controlled by a green screen VisionPro 8321 with dehumidification mode.

All flex was sized using 0.05" per 100' and all hard pipe was sized using 0.06" per 100'.
The filter grills were sized to have less than 300fpm across the filter.

For now, the plans are for +- 1200 CFM on high, 1020 CFM on High with dehu, 800 CFM on low and 680 CFM on low with dehu. I may drop these more depending on performance.

Please, be kind with your comments. I've never done anything like this before so I'm sure it's far from perfect.

I still have a whole lot to do but this is where I'm at so far. I hope to have all of the drops to the second floor done this weekend.

Thank you everyone who has been helping.

ratio

Nice! There's just something that feels Right about doing it yourself.

Bob Bona_4

The 90 plus furnace should fit nicely up there, Mr. Jensen.

ChrisJ

Bob Bona said:

The 90 plus furnace should fit nicely up there, Mr. Jensen.

Oh, that's low..............

KC_Jones

@ChrisJ I have one question. Do you sing out of tune?

ChrisJ

I don't know? If I did would you stand up and walk out on me?

njtommy

Lol I was thinking we could of done a steam coil in the ductwork.

No problems @ChrisJ just let me know when your ready for start up.

Gordy

It'll be one for the books. Looks like your going Chris J on this...

Oh pregnant wife, and crowding her bubble.......bad.!pregnant wife, and no AC worse

Bob Bona_4

I think you coined a new phrase Gordy. "Don'tgo all Jensen on me now"

ChrisJ

Here's the duct layout.
Sorry for way it's drawn, when I started I didn't know what the proper symbols were so I just made it up as I went.


Returns have a red border. Arrows do not indicate direction of flow. Also, it's not to scale, the air handler is a lot bigger than it appears in the drawing.

However, the way stuff fits and is positioned is fairly accurate.

There are no dampers shown in the 10" drops to the first floor as I'm installing them in the pipes on the second floor so I can easily access them via the two closets.

Gordy

You won't regret putting a damper on the short return duct.

ChrisJ

Ever wake up on a Saturday and not want to do anything, even though you have a ton of stuff that needs to be done?

ratio

Only on days that end in "Y".

JUGHNE

You guys that get projects completed in your own homes really ruin it for the rest of us..........

We have HW heat in our house (my hobby) that we moved into in 1995.
We were here 10 years before wife said we need AC.....something about women's Tstats change in mid life.
Most of the duct was installed when house built. Enough to move AC air adequately enough to survive. Another 10 years to complete RA so the HVAC room was no longer just a plenum.
Duct is now 95% completed.
10 years ago I completed the infloor and inwall heating in the master bath, getting rid of the electric space heater. I did this while the wife was at work and turned it on for Christmas.
3 years ago I brought my wife a water softener for Christmas,
The next Christmas I hooked it up.
Isn't she a great and understanding lady?
Her father built several houses and would only finish them before they moved.
Some old saying about the shoemaker's children going barefoot.

BobC

I love work.

Work should be cherished, if you do it all at one time you might not have any left for tomorrow. Best to be safe and make sure you save some for tomorrow.

I lied, I like retirement more.

Bob

njtommy

Lol @JUGHNE isn't that the truth. I wish I could wake up and just work on my house. My wife yells at me all the time about that.

ChrisJ

I can't complain.

This is still in our livingroom along with all of the hard pipe, flex, insulation etc. It's taking up half of our livingroom. So, she's tolerating it, so far.

The good news is, it's slowly working it's way up into the attic. The return plenum will be going up soon.

ratio

ChrisJ said:

This is still in our livingroom along with all of the hard pipe, flex, insulation etc. It's taking up half of our livingroom. So, she's tolerating it, so far.

Whoa! My complements to your wife, sir, if she's ok with THAT! I'd be eating frozen pizza for dinner every night if I did that, even after the A/C was running!

ChrisJ

After taking some final measurements I think it's time to finish the return plenum and get it up into it's home.




I bought a circle cutter + metal bits for the rotozip. Hopefully it won't disappoint. The plenum is 20 gauge.

ChrisJ

@JUGHNE @Jamie Hall @EBEBRATT-Ed

Can you tell me if it's acceptable to run ENT as a drop to my air handler? I want something that will transfer the least amount of vibration to the rafter above it. So, I was thinking 1/2" ENT with #14 stranded THHN.

I've heard ENT cannot be exposed, but this isn't in a shop or anywhere people frequent.

JUGHNE

For your purposes it has only the limitations of NMC Romex Cable.
But one limitation is max amb of 122*F. (Hot attic??)
UV light will make it brittle.

ChrisJ

JUGHNE said:

For your purposes it has only the limitations of NMC Romex Cable.
But one limitation is max amb of 122*F. (Hot attic??)
UV light will make it brittle.

Yeah, I saw that.
UV isn't a concern, but the ambient temp may be.

So ENT isn't the best choice, what is?
MC seems to rigid to me. Maybe I should just use romex as I originally planned?

JUGHNE

IIWM I would romex up the rafter to a disconnect switch mounted on a head knocker board. Then metal flex to the AH with the stranded wire. There is FMT, flexible metallic tubing which is very flexible, 6' max length ......I haven't seen it around for years.
There is FMC, flexible metallic conduit, not quite as flexible but commonly available.

ChrisJ

I'd love to know what came with my damper on the boiler. That looked like MC, but it was super flexible, as you say.

JUGHNE

Probably FMT. You could tie it into a pretty tight knot without it popping the corrugations apart. Popular for machine tool type wiring where bending space is tight. Don't know where to get it as I haven't used it for 25+ years.
3/8" FMC is pretty flexible and will hold your 3 #14's easy.
I use 3/8" FMC to rewire the controls for the old boilers I work on.
Uses the 1/2" MC connectors.... usually.

ChrisJ

JUGHNE said:

Probably FMT. You could tie it into a pretty tight knot without it popping the corrugations apart. Popular for machine tool type wiring where bending space is tight. Don't know where to get it as I haven't used it for 25+ years.
3/8" FMC is pretty flexible and will hold your 3 #14's easy.
I use 3/8" FMC to rewire the controls for the old boilers I work on.
Uses the 1/2" MC connectors.... usually.

Is there any difference between MC and FMC as far as the jacket is concerned?

hvacfreak2

Not much of a difference but yes there is between MC jacket and Greenfield . Also make sure that 14 gauge is acceptable , NEC dictates 12 for appliance circuits the last time I looked.

JUGHNE

FMC (steel or aluminum) can itself qualify as a grounding circuit.....most of the time....again the big book of exceptions. More flexible than MC.

MC usually comes with a full size green grounding wire. Usually MC conductors are solid wire, adding to the rigidity of the cable. MC sheathing (which is usually aluminum) alone does not qualify as grounding path. Then there is AC type, which just will add to the confusion.

Personally I would run #12 stranded into the air handler. Some lugs and terminals, although approved for #14, are quite oversized and seem to squash the crap out of smaller conductors.

Usually, sometimes, but not always, there are exceptions...most of the time. Now that is my direct answer, maybe.

ChrisJ

hvacfreak2 said:

Not much of a difference but yes there is between MC jacket and Greenfield . Also make sure that 14 gauge is acceptable , NEC dictates 12 for appliance circuits the last time I looked.

Not sure what NEC dictates for appliance circuits, but the manufacturer of the air handler says 15A maximum protection.

It draws all of 5A @ 240V under full load, so.....

@JUGHNE This just uses wirenuts to connect to the incoming line. Fancy, eh? I do need to remember to mark my white wires as "not white" though. I suppose L1 and L2 tags should be sufficient at all ends?


I do like the Phoenix connector they give for the low voltage connections though.

JUGHNE

Does that connector unplug so you can wire it outside the cabinet? (I usually stab the small screw driver into my palm as I hold it)...

As far as marking, My AHJ will accept sharpie marks down the side of the no longer white wire.

How long have you been sniffing that stuff anyway??

EBEBRATT-Ed

Most would use romex, MC is ok but I agree with @JUGHNE FMC flexible metallic conduit (greenfield) is good. Pull a ground through it, stranded is better than solid if you have it.

Not a fan of smurf tube, but I'm old so anything not made when I started is NG. That's why I wire to the 1974 code book, it's the one I learned on LOL

#12 for appliances, not true you can use #14 in any building if it meets the amp requirements you need.

A lot of people think all commercial buildings have to be #12 minimum wire and all conduit 3/4 or larger. NOT TRUE
Engineers draw it up that way but it's not in the code. (they get paid by a percentage of the job) People see it so often they think it's mandatory.

@ChrisJ , don't get mad but your ducts are on the LARGE size. This should be as quiet (which is good) as a church or funeral home job (not trying to be morbid) but you may want to damper all the returns. @Gordy is right The RA will take the path of least resistance to get back to the AHU. Just wondering if you will have return air where you want it.

I worked with a guy once who I thought was just plain stupid.

We had a bank and behind the teller line the girls were hot(in more way than one).

This job had a roof top unit. The supply ducts to the teller area were ok. He said ," we need to pull the heat out of here" The return duct came down from the roof through the first floor and into the basement where it branched off to floor baseboard returns.

He wanted to access the return duct in the first floor ceiling and run a branch line into the teller area.

Dumb me, said " we will have to damper the old return duct that goes to the basement so the new duct will pull air". he said no, the air will take the path of least resistance.

he was right! worked like a charm.

Some do ductwork like the returns don't matter (no not u). There just as important as the supplies

ChrisJ

@JUGHNE Yep, the connector unplugs so you can wire it while sitting down etc and then plug it in.

@EBEBRATT-Ed I can't take full credit for the duct design, Bradford White started the design, I tweaked it, and went back and forth with him over a few months. The sizes are a combination from him, and some charts I found.

My returns are all equal to my supplies, except I am concerned about noise in the big return which primarily serves the first floor. The reason being, Brad really wanted me to line it, and install a baffle. The issue was both room and money. I do have two 90 degree turns between it and the ahu, but the distance isn't that far, maybe 3 or 4 feet total. I'm using 14" hard pipe for 650-700CFM so the velocity should be good, just not much blocking sound from the fan. Perhaps that 14" damper will help some with sound as well. You can see the 14x30 return in my drawing a few posts above.

The damper was Brad's idea as well. He felt it would pull from that return much more than the further ones. I liked the idea.

hvacfreak2

#12 for appliances, not true you can use #14 in any building if it meets the amp requirements you need.

A lot of people think all commercial buildings have to be #12 minimum wire and all conduit 3/4 or larger. NOT TRUE
Engineers draw it up that way but it's not in the code. (they get paid by a percentage of the job) People see it so often they think it's mandatory.

I don't know what I was thinking , I was 100 percent wrong. It has been 25 years since I have done any line voltage work in residential , and it was our company policy for 12 gauge minimum , not a code requirement ( we did the line voltage work on our new construction jobs for our HVAC equipment ). I remember that it used to be nice on occasions where the electrician accidently pulled our furnace feeds with 14 and it was so much easier to work with than what we were used to.

In commercial work however the distances alone will often move the wire size up to 12 for 15 amp circuits so that may be a reason that most electrical contractors don't bother with it. As for pipe sizes 3/4 is easier to pull through and keep straight more often than not. But I wish they would create some standards for VRF and mini split wiring , it gets difficult if the EC connects to a wall hung with 12 mc and you have to get into it after the fact.

EBEBRATT-Ed

@ChrisJ , with that low velocity in the big return I think you will be fine. Lining is a good idea. Rooftops with a plenum return they used to say 10' of duct with 1 90 in it and line it to keep the fan noise down. But that was at normal velocity.

I have a little concern that the returns "won't balance" because they are oversized. Suppose you could add dampers later if it's an issue.

@hvacfreak2 , I don't have a problem with #12 or 3/4 pipe, just not code required. With arthritis in my hand I like #14 better LOL

Your right, voltage drop in long runs needs to be looked at

ChrisJ

EBEBRATT-Ed said:

@ChrisJ , with that low velocity in the big return I think you will be fine. Lining is a good idea. Rooftops with a plenum return they used to say 10' of duct with 1 90 in it and line it to keep the fan noise down. But that was at normal velocity.

I have a little concern that the returns "won't balance" because they are oversized. Suppose you could add dampers later if it's an issue.

@hvacfreak2 , I don't have a problem with #12 or 3/4 pipe, just not code required. With arthritis in my hand I like #14 better LOL

Your right, voltage drop in long runs needs to be looked at

I'm not so sure they're oversized.
The reason I say that is, the two 200cfm ones are a few feet of 9" flex duct. Probably about 5 feet each. The upper one shows a 10" hard pipe because I used that to get closer to the actual return grill, and then just continue with 5 feet of 9" flex for noise reasons.

The 8" one is hard pipe for about 15 feet, and then a few feet of 8" flex to the return grill.

If they are oversized, they are all about equally oversized.

As you said though, dampers can easily be added.

EBEBRATT-Ed

@ChrisJ either way I think it will be quiet and work well.

When I started I worked at an oil company. The owner was a PE but he seldom did anything with it. He spent most of his time running the oil business. But he knew what he was doing, he would design an occasional duct job. I worked at a house for a rich guy that owned a huge department store that he designed the duct system. I was impressed with it super quiet big floor mounted linear diffusers.

Lots of people hate scorched air but like anything else ....if it's done right it not bad. They always cheat on the duct size. I think some guys size the ducts for the heat loss (or gain) and forget about how much air the fan will move.

80K heat load 100K out put furnace. they size the ducts for 80k now there undersized and noisy

ChrisJ

EBEBRATT-Ed said:

@ChrisJ either way I think it will be quiet and work well.

When I started I worked at an oil company. The owner was a PE but he seldom did anything with it. He spent most of his time running the oil business. But he knew what he was doing, he would design an occasional duct job. I worked at a house for a rich guy that owned a huge department store that he designed the duct system. I was impressed with it super quiet big floor mounted linear diffusers.

Lots of people hate scorched air but like anything else ....if it's done right it not bad. They always cheat on the duct size. I think some guys size the ducts for the heat loss (or gain) and forget about how much air the fan will move.

80K heat load 100K out put furnace. they size the ducts for 80k now there undersized and noisy

I hate to admit it, but I believe this is true, forced air systems apparently can perform very well but rarely do because they are poorly designed.

Next big hurdle in the project is this hopefully fake beam in our living room. I need it gone so I can install a 12x12 diffuser there. I started digging into it but chickened out and decided I'm not comfortable messing with it so my dad is driving down this weekend to take care of it.

I can't see how it could be anything other than fake, but I also can't figure out why it exists so I figure it's best a carpenter of 40 years deal. This way if it really is doing something maybe he can figure out a work around.

The alleged fake beam.





There's no post or beam inside the wall on the left, and there's nothing below it except my basement to carry the load. The joists also go in the same direction as the beam, so I believe anyway. But, in such a old house who knows what went on.

Gordy

Could be who ever did it wanted something to define the two spaces. If there is no load carrying members below the support points of the potential beam. That is if you are certain the joists run parallel with the beam in question.

If the joists run perpendicular the beam may have been a feeble attempt to help carry the joists above. The individual may not have understood that the load bearing supports must follow through the structure to the basement to carry the loads.

JUGHNE

Is the "beam" taller on the right end than the left?
Some remodeling I was involved with, we would put a false beam in to distract from the differences say in ceiling levels. Or create the different spaces. Or the walls didn't line up and the beam would "fix" all that.

ChrisJ

JUGHNE said:

Is the "beam" taller on the right end than the left?
Some remodeling I was involved with, we would put a false beam in to distract from the differences say in ceiling levels. Or create the different spaces. Or the walls didn't line up and the beam would "fix" all that.

I measured and best I can tell the ceilings are the same height on both sides of it.

There used to be a wall there, judging by the patch in the floor.

The good news is, the one section was a dining room when we moved there, so I'm hoping it's as you and Gordy said, was used to create a different space.

I got concerned because best I can tell, they built it out of two 2x6's or something. As soon as I found it wasn't hollow drywall I backed down from it and called the ol man for help. Though, it is hollow in the center just not the sides or bottom.

Gordy

Wouldn't be a chase for wiring, plumbing, steam pipes would it?