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aeridyne 01-07-2011 10:29 PM

Installing All New HVAC system
 
So, I've got this great story, about a guy who bought a house for his sister, yet to be born niece, and himself. It's a long one, and a good one, suffice to say, it's been a long hard road with more bumps in it than I ever could have imagined. Long story short, here's where I'm at...

I didn't know a thing when I bought the place, not even what a floor joist was, turned the heat on for half the month of March with the thermostat down as low as it would go, and the bill was still $260 for half the month! That's when we realized, it has serious issues.

So me and pops started taking a few walls off, revealing the "subtleties" of a house that was built by a diy'er back in 1947 with a few additions here and there. Lets just say we found a few interesting sports pages from the news paper circa 1950s if that gives you an idea of what we found for insulation in the walls. That was one of the first of our discoveries, and the more we took things apart and looked, the more problems we found. Essentially I ended up having to take the house down to the studs of the first floor and left most of the 2nd level floor intact, had to dig up the foundation and fix some things there, modify add beams and beef up the structure and frame up. We framed it over the winter last year, got a roof on it, windows in, and siding on. Since then I've got the plumbing roughed in (did that before the HVAC because there was absolutely no wiggle room for it, 2x6 joists meant everything had to be just right). So now I'm on the HVAC portion, and I've done my best to read as much as possible, attempted a Manual J, have tried to figure out where to place the duct runs and trunks where they make the most sense, and so I loose as little as possible head room in the already low ceiling basement, and try to design the sizing as such as well as I can, but I'm having a really hard time and not doing well with it at all honestly. So, that brings me here, in hope of some sage wisdom and guidance.

Thus far I have bought a used furnace and AC condenser unit. The furnace is an Amana high efficiency 92% pvc venting type. I've installed a concentric kit through the band joist and have it hooked up temporarily without any duct work, but I really don't like firing it because it mainly just heats the crap out of the basement, but that is also keeping the frost at bay down there so it's doing something for now.

Obviously I know that it's going to be nigh impossible for anyone to tell me how to size all of my ducts etc without a lot of information and a floor plan or something to go from. That's not so much what I'm looking for though, although if it's possible, that would be awesome, I have all the data off the top of my head even for square footage of each room, window sizes and U factors, wall R values, and so on. I figured the chances of someone being out there willing to plow through a manual J and D with me were fairly slim.

I've been trying to learn how to do all of this properly, and also how to integrate an HRV system, but again not having a good time of it. I'm also pretty short on money, so buying really expensive college text books or registering for the ACCA and buying their materials probably isn't going to work so well for me. I guess I'm hoping there are resources out there that can actually teach me without having to understand blasted thermodynamics how to size and assemble the plenum and duct work properly and integrate an HRV system.

All constructive input I assure you will be appreciated. Any questions for clarification, ask away. Thank you.

hvaclover 01-08-2011 02:43 AM

good luck.

beenthere 01-08-2011 04:47 AM

Your local library may have a copy of Manuals, J, S, T, and D.

ACCA has free down loadable spread sheets for J, D and I think S.

hrjrkr 01-08-2011 06:34 AM

There is a program out there that you can buy and use for 30 days and it is very good. You fill in all the info. They are very thorough as far as asking you about insulation in the walls and even what sheathing you have for walls. You send them all the info and layout of your house and they will design you duct work. You can also talk to a tech if you have questions.

aeridyne 01-08-2011 11:31 AM

Quote:

Originally Posted by beenthere (Post 565311)
Your local library may have a copy of Manuals, J, S, T, and D.

ACCA has free down loadable spread sheets for J, D and I think S.


I had found those, and I downloaded them, started plugging in all the data, but then realized that you need the Mj8ae to finish it because some of the data you put in is from that manual and I don't have the 75 dollars to get it.

I also found a program with a 30 day trial which may be the one you had mentioned, hvac-calc. I've tried to use it but can't seem to get it right, there doesn't seem to be anything to differentiate the walls in the individual rooms as exterior or interior, I thought that was solved by using the "all rooms" option for each level, which it appeared you had to put in otherwise some of the rest of the options could not be filled out, but the calcs seem to be off. Something different and preferably free would be nice even if I had to do a bunch of calcs manually, like I said I know all the floor areas, R values of the walls, window U values etc, but I can't seem to find a good free program to use that I can figure out.

I suppose it is possible that if I had a proper manual J worked out that I could send it to someone for the D, but I need to get an actual good Manual J done first before I potentially take that step, and I think I'd rather try to do the D myself somehow because the assembly is going to have to be quite customized for the house I need to build it for, essentially 4 levels with the basement, two main levels and the relatively large sealed attic space.

beenthere 01-08-2011 12:15 PM

With HVAC CALC. You don't enter the inside walls. just the outside walls of each room. Its in the directions, and the video.

aeridyne 01-08-2011 05:17 PM

Quote:

Originally Posted by beenthere (Post 565509)
With HVAC CALC. You don't enter the inside walls. just the outside walls of each room. Its in the directions, and the video.

really? ok, so say i take out the walls that aren't exterior, how do I specify a room that is interior? Just by floor and ceiling space? And do I still need to do the "all rooms" for each level?

Also another thing that really threw me off was on the top level, which would normally be an attic space, I have built the roof assembly custom so that the insulation is in the rafters, thus, it's like a bonus space, but there really aren't any walls, the rafters run all the way to the floor at the outer walls, the total dimensions of the rectangle are about 28x36 with a 10/12 pitch lengthwise, so there is a decent amount of floor space at a full 8 ft and the rest is pitched, I wasn't sure how to put it in to the program, so I just did "all rooms" for that level and put the wall height at like 3 1/2 feet.

beenthere 01-08-2011 05:33 PM

With the exception of floors. I HVAC CALC you only enter those things that gain or lose heat. The floor defines the room.

Your second floor ceiling is done with you entering the expected temp diff between the attic and second floor. If your not going to condition it. If your going to condition it, then the second floor ceiling is not included in the calc.

For the attic. use the sq ft area of the walls, instead of the dimensions. Enter the ceiling sq ft area, or dimensions, they don't have to be the same as the floor.

Its been a while since I used that program. But it is a nice program.

aeridyne 01-08-2011 06:59 PM

Quote:

Originally Posted by beenthere (Post 565697)
With the exception of floors. I HVAC CALC you only enter those things that gain or lose heat. The floor defines the room.

Your second floor ceiling is done with you entering the expected temp diff between the attic and second floor. If your not going to condition it. If your going to condition it, then the second floor ceiling is not included in the calc.

For the attic. use the sq ft area of the walls, instead of the dimensions. Enter the ceiling sq ft area, or dimensions, they don't have to be the same as the floor.

Its been a while since I used that program. But it is a nice program.

Ok thanks Beenthere, I'll give it another shot and see what I come up with, hopefully I can bang out a decent manual J here for starters! :thumbsup:


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