DoD vs. Overcool
To BaldLoonie... OK, so......
DoD - slow blower down to decrease humidity but don't change temp setpoint.
OverCool - run system longer to decrease humidity by "drooping" temp setpoint.
Two solutions for humidity removal, different results. I got it.
You got it!
The IAQ can do both, just not with the 16i setup. My IAQ has never used the overcool function, I do use the DOD function in mild but humid weather.
Theoretical Conversion of xL16i to xL15i
Feel free not to answer, but as an engineer who designs things, I always love to theoretically solve something. I have no intention of messing with my system as I don't have a humidity problem so this is strictly "what if". I'm actually waiting for next summer to see how/if xL16i improves my electric bills over my 15 year old unit......
1. Couldn't an xL16i AC be converted to single stage AC (same as xL15i) by simply jumpering Y1 and Y2 together at OD unit. I don't have xL16i schematic in from of me so it might actually be connecting single stage to just Y2, I'd have to first review schematic of xL16i to be sure...and wiring that jumper to just Y1 of a single-stage Tstat.
2. At that point, you could wire XV95 to IAQ TStat just like you would do for an xL15i......
The more intriguing, albeit complex solution would be to run xL16i in 1st-stage to get lower energy cooling, but then slow blower to 80% of 80% (which is about 65%) to increase humidity removal in first-stage. Doesn't Ylo typically force blower to 65%... See where I'm heading...
This last one would require a knowledgable person to first analyse the OD/ID/CFM equip to get latent and sensible numbers, etc.... But the theory is, could you reduce blower speed in the 1st stage cool to provide a more low cost DoD than that provided by a single stage xL15i.
You can add a control to run it in second stage, if you have high humidity. But keep the blower at 80%, instead of leaving Comfort r time it up.
Sounds similar to what was done to my XL15i but for different reasons (high static pressure). Comfort R was shut off, the BK jumper was cut, Y& O were jumpered....and the XV95 runs at 80% air flow 100% of the time when the XL15i is on.
In the land of the blind.....the man with one eye is king....
beenthere - Good point, that would essentially duplicate functionality acheived by a xL15i.
Once I was typing, what intrigued me was if running a 3 ton xL16i in its first stage (27,200 Total vs 34,400 Total in 2nd stage) along with reducing the blower from 80% to 65% provide an even lower energy cost solution for DoD over say a 3 ton xL15i with 80% blower... By way of comparison, I'm now wondering if xL19i does DoD and if so do they use just 1st compressor with what blower speed...
The 19i, wires up like other brands 2 stage do. It does much better then the 16i.
And it does DOD with blower slow down..
there is no combination "without getting real innovative" that will achieve 65% airflow!
Originally Posted by wraujr
What does Speed does Ylo give on a XV95
Agreed. But I was wondering why Trane went thru all that trouble with BK to get 80% blower and why not use Ylo... So, I assumed that maybe Ylo gives 65% so it wouldn't have to be too tricky... Searched XV95 installers guide and service facts and couldn't determine what blower speed Ylo gives compared to Y at 100%.
Originally Posted by wraujr
Y-lo is 50% blower speed!
Y-lo without BK its 30%
I've just received a preliminary proposal for my trane system based on the Man J (v. 8).
Trane XV80 VARI-2STG TUD100R9V5K(C)
TRANE XL15I 4TTX5042B1000A
Honeywell IAQ stat
ARI REF # 1416270 (a/c+coil)?
ARI REF # 1421325 (furnace+a/c+coil)?
Heat Summary Total: 67086 Btuh
Sensible: 26562 Btuh
Latent: 8483 Btuh
Req. Total capacity at 0.70 SHR: 3.2 ton
Does this system matchup look acceptable (optimal)? Apologies if I’m leaving out important data.
This proposal is the 2nd highest bid, price-wise, but that’s OK because I trust this company. They’ve been in business for decades with a much better-than-average reputation. I figure keeping quality employees and doing quality work costs money so I think the price is more than acceptable.
By the way, this was the only company (out of 3 total) to insist on doing a Man J without prompting. The other two companies based everything on square feet plus "adjustments". After an initial assessment of my current system, this rep. stated they needed to do the Man J (he didn't call it that). I gave him the original house blueprints. Later that day, an engineer called me at home and asked a series of additional specific questions for the Man J calculation. I was stunned!
Originally Posted by mikeinomaha
My only suggestion - get a XV95, jeesh.
"My only suggestion - get a XV95, jeesh."......larobj63
I get the feeling you're indicating the XV95 is a "no-brainer".<very big grin>
Trying not to be too dense, but why specifically? The cost difference would not be insignificant and there's a 50/50% chance dear wife and I may have to move in 5-7 years. In addition, fresh air/vent run to the outside is more complicated (more cost) due to a finished basement. Obviously, high-efficiency is nice, but initial cost and potential lack of return on invested dollars can't be ignored. In your expert opinion, considering the above, would you still spend the extra cash?
I'm not trying to challenge...just honestly don't know. I will have the rep. run the numbers with the XV95, though.
And by the way, thanks,