Variable speed air handler settings

Gordy

You need to wear less clothing in the homestead.

ChrisJ

Gordy said:

You need to wear less clothing in the homestead.

You run that suggestion up the flag pole and let me know who salutes it.

Charlie from wmass

I am all for it. Note I can not see @chrisj from my house.

ChrisJ

Nice.

ChrisJ

81F 64% outside right now.
Nothing has had a break, first floor is 76F.

I can't wait for winter.

Gordy

I'm going to need a sweat shirt.

Gordy

ChrisJ said:

81F 64% outside right now.
Nothing has had a break, first floor is 76F.

I can't wait for winter.

I seem to remember you like the house at 72 in the winter. ......

ChrisJ

Not exactly. I like 70 and keep the bedrooms around 64f using TRVs. The wife likes 72f likely due to cold floors in the kitchen and cold walls and windows everywhere.

SWEI

Eerily similar here:

Gordy

That certainly is Kurt.

ChrisJ

I think I may have found what I've been looking for, but I'm confused. Why would a 14 SEER unit have such a huge difference between high and low output while a 16 SEER doesn't?




I assume these are all sensible cooling numbers?

GW

So get a two stage ac?

ChrisJ

GW said:

So get a two stage ac?

That's what I don't understand on this chart, these are mostly single stage.

ChrisJ

How's it look?

KC_Jones

Wait you added a furnace to the equation? That makes me sad.

ChrisJ

KC_Jones said:

Wait you added a furnace to the equation? That makes me sad.

Yeah,
The furnace is certainly the worst part of that picture......

ratio

You went with a zone panel too? Oh, boy...

ChrisJ

I'm over here spending weeks trying to get my runs of flex as short and straight as possible, meanwhile that disaster pops up on my facebook.

Right now it looks like most of mine will be 2-3 feet and likely dead straight. I don't want any longer than 5 feet if I can avoid it.

Also considering R8 fabriflex for it's acoustic properties.

Techman

ChrisJ, my friend, What system has ONLY 5' of duct run? My mind's eye is fuzzy here? Are you using "dampers" on each and every takeoff?

ChrisJ

Techman said:

ChrisJ, my friend, What system has ONLY 5' of duct run? My mind's eye is fuzzy here? Are you using "dampers" on each and every takeoff?

@Techman
5' or less of branch run which will be R8 nylon flex duct pulled tight and fairly straight.. The trunk is to be hard piped, I believe 14" round and about 15 feet in each direction. Dampers at each branch, I'm hoping for bell mouth connectors, but we'll see what I can find and the cost etc.

I expect the trunk and any steel ducts to be made from 20 gauge galv sheetmetal which a friend is helping me with. We're using 20 gauge because that's what he buys in bulk. I've got two 10" round runs to the first floor which will be hard piped as well as an 8" return that I need made primarily metal (about 10' run) with a short flex connection at the ceiling box.


Everything is being done with ceiling diffusers and all returns will have filters.

Oh, and I'm planning on plumbing a Megnahelic into the return so I can monitor my filter life. The steam system has one, so why not, right? The wife already OK'd a panel mount version in the wall.

ChrisJ

Stuff is finally starting to come in. Nice!

So far, the two 10" 3 way diffusers for the two large bedrooms, the 10" diffuser for the middle area and a 10x10 filter grill for the small bedroom are here.




Feels kind of odd buying air conditioning stuff as fall sets in, but I'd rather be doing it now than in the spring.

Next will be two 12x12 filter grills, a 14x30 filter grill, 8" 2 way diffuser and two 12" two way diffusers.

All rectangle duct a friend is helping me fabricate from 20 gauge steel.


Here's my plans after many many changes. They're not perfect, but I'm happy with it overall. Thermostat location isn't finalized yet. The btu/h listed is from the heat gain survey and I don't necessarily agree with the numbers. For example, I feel a few are too low, and others are too high etc.

All flex connections are short and will be made using Hart & Cooley F218 flex, fairly straight and tight with 90 and 45 metal elbows were required. I tried to get nylon flex acoustic duct, but had issues. My duct losses should be reasonable as most of it is oversized, for example I expect 9" flex to carry 175-190 cfm. 8" 120-130 cfm etc. The system should flow fairly nice.

The 10" 2 way diffuser is actually on the large side for the middle area on the second floor, but I didn't want to be launching cold air at the big return any further than I had to. The 10" will only throw 5 feet or so. All other diffusers will be operating at a higher velocity.

I also want rubber duct isolation at the air handler, which isn't shown in my drawing.

I also have a Magnehelic coming to permanently plumb into the return for filter monitoring. The boiler has one, so why shouldn't this?






Like I said, it's not perfect but I think it's the best I can do at a reasonable cost for my family's wants and needs.

@JUGHNE Thank you for recommending using closets for duct work etc, before that I had never even considered it.

JUGHNE

IMO using a little extra length of flex helps to reduce the noise of air flow. FWIW

We are probably anxious to get the reports next summer on humidity control in your house.....with the over sized capacity and all

ChrisJ

JUGHNE said:

IMO using a little extra length of flex helps to reduce the noise of air flow. FWIW

We are probably anxious to get the reports next summer on humidity control in your house.....with the over sized capacity and all

Still going to disagree with such statements.
Since my operating temps are always lower, my system will be no more oversized than anyone else's. Not to mention the air handler has a dehumidify setting that will run it on it's lowest speed setting.


Also just ordered one of these bad boys. I've already got a 0 - .25" but I'm thinking this one will work nice piped across the air handler permanently.

ChrisJ

@Techman Check your PMs

JUGHNE

I service the HVAC for 4 phone "switch" buildings. These were formerly owned by the Bell/AT&T system. I can see the remains of their air filtering monitoring system. They used a pre filter before the main filter. Pressure transducers would see the difference as the pre filter plugged. Also they could see if the indoor fan was running. The Midwest area was monitored in Denver, (600 miles from me), I think they got a good deal on dedicated long distance lines. This was all done thru an "Andover" system.........all this technology has been replaced by me .

Your filter grills will only handle a 1" filter?? You could put a high Merv 5" filter right at the AH also. If your blower had the stones to handle the increased static that is. You could monitor the drop across that mega filter to see change as the 1" plugged.
General Filters has a whistle to install and adjust to tell you when your filter needed attention. Have some but never tried them.

ChrisJ

JUGHNE said:

I service the HVAC for 4 phone "switch" buildings. These were formerly owned by the Bell/AT&T system. I can see the remains of their air filtering monitoring system. They used a pre filter before the main filter. Pressure transducers would see the difference as the pre filter plugged. Also they could see if the indoor fan was running. The Midwest area was monitored in Denver, (600 miles from me), I think they got a good deal on dedicated long distance lines. This was all done thru an "Andover" system.........all this technology has been replaced by me .

Your filter grills will only handle a 1" filter?? You could put a high Merv 5" filter right at the AH also. If your blower had the stones to handle the increased static that is. You could monitor the drop across that mega filter to see change as the 1" plugged.
General Filters has a whistle to install and adjust to tell you when your filter needed attention. Have some but never tried them.

I've thought about running a filter at the air handler as well, but I'm concerned it would just be too much load on the blower?

I'm planning on MERV 8 filters in all of the return grills.

Besides the 0 - 1" Magnehelic, I also picked this one up. I think it may be too sensitive though, but may work to monitor a single filter, such as one back at the unit?

It came with the Dwyer case, the hanging standing bracket and 2 lengths of hose which is nice.

I've got an issue with buying these things, I'm up to three now.

Canucker

@ChrisJ that gauge you have pictured is the one we use to measure the differential pressure of the finished product handling rooms that have multiple filters.Very nice gauge. Our spec to use the room is a difference of 0.05 in or higher. They usually sit around 0.1 to 0.4 with a short length of 1/8" inch tubing. I'm sure you could set it up to put on your manifold that will house your steam gauges too

ChrisJ

So,
To continue this where I'm at now, I've found Carrier (actually, Tempstar in my case) gives a hell of a lot more information on their products which is nice. I ended up looking at Tempstar because a local distributor in our town that I deal with a lot sells them.

I'm a bit confused on why they list several different size air handlers for each size outdoor unit. Meaning, a 3 ton outdoor unit coupled with a 2.5 ton, 3 ton, 3.5 ton and 4 ton air handler, or as they call it, fan coil.

It looks like the 3 ton and 3.5 ton indoor unit running at 3 tons both provide identical results? Is this the case, or is there far more to this story?





The units I have highlighted aren't variable speed, but rather use X13 motors.

SWEI

The different coils are going to give you different SHRs.

ChrisJ

SWEI said:

The different coils are going to give you different SHRs.

May be a stupid question but I'm having a brain fart.

Isn't S/T on the chart for sensible vs total? Meaning they're all 0.74 so they claim there's no difference.

25,308 sensible, 8,892 latent if I understand correctly.

SWEI

Larger evap area = different temps. I'm a bit outside my knowledge envelope here, but Harvey will know the correct term to use.

ChrisJ

SWEI said:

Larger evap area = different temps. I'm a bit outside my knowledge envelope here, but Harvey will know the correct term to use.

True,
Larger evap area, but still moving the same CFM so the temp should remain constant.

What I don't see, is what CFM is used for those results, perhaps 1200? Not sure if 400 cfm per ton is the standard for SEER ratings or not.