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ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
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THINK I MADE A POOPIE




kastein posted:

The furnace will be natgas fueled forced hot water radiant, I've bought it and it's sitting in teh living room waiting for me to install it and all the heating stuff. Due to the way the house is built and my dislike of chopping up major structural beams, I won't be doing central air for HVAC, but I do have an extra fairly useless area of the attic available for an evap unit and wouldn't mind putting the condenser side on the roof or outside if necessary, and there's plenty of space in the rafters available for AC air ducts to the 3 bedrooms and upstairs hall. Thus, I'm considering that route. I'd really like to avoid minisplits simply because I don't like how they look. I'm also not afraid of doing the AC install work myself if it saves some money, I've got all the equipment (gauge set, can taps, vac pump, experience, etc) to do automotive AC repair and recharge, plus everything I need to braze AC tubing, so I'm not really averse to learning how residential AC is different and getting any EPA certs I need to handle the refrigerant they use.

Good to know about those types of flooring - thanks! I always wondered how people avoid a repetitive "wood" pattern, guess the answer is they don't really. Fortunately the style we liked the most was a natural woven bamboo style, at least for the bedrooms, so there's no repetition. For the kitchen and dining room I'll just have to be careful to not make it look copy/pasted if we go with a screen printed style.

If you're going this route, like anything, it's all about planning. Trying to set it up so you have the correct equipment size, correct duct sizing, correct everything. The life an efficiency of and AC unit is pretty much all done in the setup.
The install work is the easy part, that's just connecting tubing, making boxes and running wires. But doing all the heat load calculations and stuff is where you have to put some time in.

Then there's adjusting the charge, getting the correct subcooling and superheat, and all sorts of other fun stuff. It's a bit more complex than dumping a can of keyboard duster in an car AC system.
Not to say it isn't doable. If you're serious, I'd recommend picking up a ductualor form Trane to start. You'll need that to start sizing ducts. I've still got a bunch of papers on calculating heat load and ductsizing and stuff too, if you're so interesting.

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ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Hey, so a bit ago you mentioned you were thinking about running A/C, at least upstairs right?
If you're still considering that, even if you aren't getting the air handler and condenser right now, you might wanna start planning ahead for that. I don't mean starting ductwork and stuff, but you might wanna consider running some pipe downstairs (Unless you're gonna be that rear end in a top hat that puts the condenser on the roof :v:) So you can running it properly. And also avoid the possiblity of having to put up some ugly looking lineset covers.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Eh, as long as you have some space for running lines, I think you'll be fine.

What I was going to suggest is that you'd run them down the wall with hard pipe, get some unistrut and vibro-clamps, the kind that goes around the insulation, you'd be set for the next 30 years.
But, as long at you've got some way to secure them at the top and bottom of the chase you'll be fine.

And as far as running ductwork goes, it doesn't necessarily have to take up all the space there. This depends on your plans for where you put the air handler. If you put in the attic, you'll need to suspend it from the rafters, and leave space under it for the auxiliary drain pan. Which means you'll also be suspending your ductwork. Which will free up your floorspace a bit. Enjoy doing lots of duckunders though. Or, if you have enough vertical space in the attic, you could set the AHU vertically, and run the duct along the peak.

Or, depending on how you've got things built/planned out already, you could build a little closet for the AHU. Build a return box out of ductboard under it, stick a vent facing the hall, and you're good to go. This will also help you free up some space in the attic, as you can run the duct along the attic floor.

And this largely depends on what you're doing for duct materials, IE Metal or Ductboard or Flex, and how you're gonna be running the trunk. If you can post a floorplan with some measurements of the room size I can do some calculations to help come up with a decent layout for you.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




I feel something like what guy has going on is really more of Kastien's thing:
https://www.youtube.com/watch?v=channel?UCd50A5qLv8FemVufSvDgkCQ

Plenty of space for living, and shop space, and then some!

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




You really dont. One gauge set can read pretty much all pressures, as long as the low side goes high enough. You can always just swap out the gauges themselves instead of buying a whole new manifold.

Or buy digital gauges and be done with it.

More importantly though, if you're doing this, you're going to need a proper micron gauge and nitrogen and a scale.

So, I know you have a bit of experience with car AC, but doing home AC is cosiderably more advanced than just slamming some computer duster in a prebuilt system.

So, have you picked out you equpitment yet? Is it properly sized for the space you intend to cool?

How high up is the AHU going to be? You may need to install an oil trap if you're going from the first floor all the way to the attic.

Have you left room for ducts? Do you know what material you'll be using? Do you know where the return is going to be? Have you left access for filter changes?

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




OK so:

Scale- As long as it can be zero'd out to weigh in the charge, you should be fine.

Nitro- I'm really not sure about argon. Generally you use nitro for two things, for leak testing, and for purging when you braze. ( This is so you don't end up with a bunch of oxidized cap flaking off) It works because it a dry gas, so you're not introducing moisture to the system.

SEER- Basically refers to the energy efficency of the unit. To get fancy:

Seasonal Energy Efficiency Ratio (SEER): This is a measure of equipment energy efficiency over the cooling season. It represents the total cooling of a central air conditioner or heat pump (in Btu) during the normal cooling season as compared to the total electric energy input (in watt-hours) consumed during the same period. SEER is based on tests performed in accordance with ARI 210/240.48

In the U.S. SEER is defined as the ratio of cooling energy in BTUs (presumably BTUs/hour) to energy consumed in watt-hours.

Tonnage- Ok, for 750~ sqft, you only really need a 1.5 or 2 ton unit. 3-4 is a bit overkill

Ductwork- As far as ductwork goes, you want to have a central trunk line with smaller ducts running off it for the drops.

Metal duct is great, will work extremely well. Insulating it cab be a bit of a project though. Hope you like feeling itchy and sweaty. :v:

As far as sizing and running things go, you can a thing called a ductulator from Trane that'll help with the calculations for properly sizing your ducts and drops.

I can also help with this.

As far as the return goes, you want to keep it somewhere central, like a hallway, or common area, so it can suck in the most air. If space is tight in the attic you'll probably be best going with a filter back grille so you can just change them without c
Having to go in the attic.

E; Also, for the AHU, if you're mounting it in the attic, make sure you have enough room to hang it and an auxiliary drain pan under it.

Trust me, you'll want to do this so you're ceiling doesn't collapse when it overflows when the drain line backs up.

ExplodingSims fucked around with this message at 15:08 on May 3, 2017

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Yeah, insulating ducts sucks. You gotta roll out that fiberglass stuff, tape it, mastic it, all while getting sweat in every crevice on your body.

Protip: Work from the furtherest duct back to the AHU so you can enjoy the cool air it puts out while you work.

As far as hanging the AHU goes, that's not so bad, you just need unistrut and all thread. Just make sure you don't block off the access panels.

As far as the drain goes, for the drain from the AHU you just need to put a P-trap in there, preferably close to the unit, and then yeah, just run it down.

For the drainpan, I like to put something with a ball valve in there, you you don't have to vacuum it out when it fills up. Make sure you keep the main drain and aux drain lines seperate.

And yes, float switches are a thing. I'm not sure what code calls for up there, but here you need one on the AHU and on the aux. pan.

As for ducts, don't just slam the biggest thing you can fit on there. They need to be sized properly for correct airflow and pressure. The calculations really aren't that hard, it'd mostly just getting sqfootage.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




You can absolutely use vibration dampening things on the AHU supports. I see a lot of places use the spring ones, so you could probably use that.

You can also put these little rubber pads under the AHU so it's not sitting directly on the unistrut. The will keep it quiet, and help keep the box from getting deformed.

They're called iso-pads, little waffle shaped rubber things.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Looks simple enough. When I get home with access to a real computer I can make up some basic plans for you. Although it looks like you shouldn't need much.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




The 13 SEER thing is nationwide, if not worldwide. Has been since 2005.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




It's not an open return in the garage, that would be dumb.

The AHU is in the garage, and had a ducted return going to it. Everything is nice and sealed.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




I wish I knew half as much as you did about framing and drywalling and such, but alas. I can certainly tell you how to keep your place cold though!

I also had a few more questions as far as your A/C plans go.

Are you doing straight cool or heat pump? After talking to some other people from up north, a thought occurred, since you live where it snows, you may need to place the condenser on feet to raise it up a bit off the snow if you plan on running it in the winter. You'll probably know more about this though, seeing as you actually have to deal with said snow. :v:

Also, I got linked to these products which are pretty nice and make the exterior penetrations look a lot more snazzy: http://www.airexmfg.com/

Also, if you haven't run any cabling, or drywalled over the area where you plan on putting the Tstat, I'd highly recommend running some 1/2" conduit and mounting a single gang box there. Turned sideways the holes line right up with the Tstat mounting holes.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




It's exactly the same as any other A/C unit, except it has a reversing valve in the condenser to redirect the discharge inside, to provide heating.

The reversing valve:


It's just a solenoid mounted on top of a u-bend that slides back and forth.

E. The only thing that's really different is that it also has a defrost timer on it so it doesn't turn the condensor into a block of ice while it's running.

ExplodingSims fucked around with this message at 00:20 on May 11, 2017

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




The Locator posted:

Doesn't the condenser (or whatever the radiator thingie is) in the air handler have to be stronger in a heat pump since the pressures are much higher when it's in heating mode? I had to replace one a few years ago because it failed during the winter, and the tech told me that it was common for them to fail in the winter due to the higher pressures compared to when they were in cooling mode.

That would be the Evaporator you're thinking of! :eng101:

And as far as I know, the Evap in air handlers are pretty universal, and can be used interchangeably. Now the issue might have been, especially if it was a newer evap, that it was made out of aluminum. Most manufacturers seem to be having trouble figuring out how to properly make and join aluminum tubes.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




And this is why I went into HVAC and not plumbing or anything. gently caress that noise. :v:

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




So did you buy a NutBuster yet? :v:

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Just don't put your stairs in there too securely, you might need to pull them back out if your're gonna squeeze an air handler and ductwork up there :v:


Darchangel posted:

Also need to re-insulate the rigid ducts, but gooooooood I don't want to do that.

Ductwrap is a product of the devil and this is something you should 10000000% hire out to somebody else. Trust me, being covered in sweat, in an attic that doesn't breath, while working with fibreglass is the worst thing in the world.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Having nice, cold, dry air on demand is always worth it.

Sucks that even the minisplit wouldn't fit in the attic, but sounds like you've got a backup plan at least.

ExplodingSims fucked around with this message at 01:35 on Jul 12, 2018

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Yeah the Midea units are pretty nice size-wise. They're also whisper quiet. The first time we installed on we thought something was wrong g with it, because we didn't hear any noise at the AHU.

But then we felt the vents and could feel air moving. They're just that quiet.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Look up local sheet metal shops, most should be able to hang out some good ducts. But, as others have said, going union makes a big difference.

The biggest thing will be making the transition pieces for the supply and return sides. But all you need for that is the cut sheet for the AHU so they know the dimensions of the opening.

Also knowing what size ducts you're going to be installing and which style.

Square, round, Spiral round, etc....
And also if you're doing interior or exterior insulation.

ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Yeah, either inside or out, you wanna make sure you have some kind of insulation on the ductwork there, unless you enjoy getting condensate all over your fresh new ceilings.
If you're doing metal duct, supposedly it's better to have the wrap on the outside, since it provides a smoother surface for the air on the inside of the duct, but in reality, I've never really seen it make a significant difference either way. And also, Ductwrap is a product of the devil. So there's that too.

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ExplodingSims
Aug 17, 2010

RAGDOLL
FLIPPIN IN A MOVIE
HOT DAMN
THINK I MADE A POOPIE




Eh, it should make that much of a difference. The exterior ductwrap is only like an inch or so thick.

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