IMO, controls are like paint color. Every car has paint. If the paint is hand applied and hand rubbed, it costs more money. When the average car is traded every 4 years, the quality of paint is a dubious distinction that is snob appeal only.

If a condensor has a grille covering the coil fins, it may look more attractive, but it is harder to keep clean. When the coil is dirty, the system does not perform to specifications. It dies quicker. A fibreglass housing may look cute, but it will self destruct quicker than metal.

I was hoping someone would know the systems well enough to comment if the Infinity does better what is most important to me, dehumidification. Do both systems have sensors of the incoming and outgoing air temp and humidity? Do they both use this data to varry the blower speed. Does the infinity controller also vary the condenser fan speed, unlide the Trane 16i. I've seen comments that they Infinity has the best dehumidification over the variable speed Trane counterpart, but I don't understand why this would be true.

If the Infinity does this significantly better, I want it, but if I won't really notice, the Trane is cheaper on the 3 system purchase.

cdavidh

First of all, both of these systems are top of line, time tested systems. Here is your dilemma.Trane makes great heat pumps but Carrier has a superior overall system with their Infinity controls which handles summer humidity better. Trane's 803 stat's method of humidity removal is by overcooling. Carrier's Infinity measures humidity against the setting on the Infinity control and cuts system on low until humidity setting is satisfied. Much more sophisticated. And while I do like Trane equipment better, Trane should hang their head in shame because they are behind the curve with this issue.

Both Trane and Carrier offer rebate programs at this time. Unfortunately, I don't believe Trane's XL16i HP qualifies for Fed Energy Eff tax credit. Don't know about Carrier. I suggest you check with both dealers.

Is this new construction? Have you considered zoning off one or two systems?

Hope this is helpful.

My opinion.

Hi, Tigerdunes.

If I can hijack this thread a little, we're installing, in new construction, a 5-ton XL19i HP for the downstairs and a 2-ton XL16i HP for the Master Suite upstairs. Upstairs will be one zone, but downstairs will use the Honeywell EnviraZone system to divide one zone into three. We'll also have two CleanEffects and variable-speed air handlers. My HVAC contractor said he'll use Trane 803 stats, but in reading the specs, I don't see where they're communicating. I'll be installing a home automation system that has HVAC control and needs bi-directional communication. I believe Honeywell makes the Trane 803, so I found the VisionPRO IAQ stats on the Honeywell site and the EnvriaComm RS-232 adapter that hooks up the EnviraZone to the home automation controller. I also have to find how to hook up the upstairs zone to the automation. I'm flying down to Florida this week to meet with the contractor. Do you know if the IAQ stats can do the job? Is there a better solution that will work with the EnviraZone and home automation?

Thanks for all your help,

Kevin

for both cdavid and Kevin

If you are interested in the Trane products and their Spring 07 rebate program, then I don't believe the Honeywell equivalent of Trane's 803 stat would qualify you for the program. I suggest you check the rebate details on Trane's website along with your quoting dealer.

Now to Kevin. I am not an expert in zoning controls and suggest that you get an opinion from someone like BamaDude who should have experience and knowledge in this area. Perhaps he will see this thread and comment.

Kevin, your post raises a question that stands out. How big an area is the 5 ton XL19i supposed to handle? 5 tons-three zones. What are the sizes of each zone? This needs to be examined and reviewed very carefully for correct size.

IMO
TD

finesse,I have not used the 803 with any of the zoning panels.I would ask the contractor if he has used the 803 with the enviro system before.The 803 is very versitile but I dont think its going to do what you want.I dont use much damper zoning.The zoned systems that I have done in the past was using the Trane zone panels and controls.If you ever successfully get the Trane zoning system set up,wired and working correctly with a proper design you are a border line genuis.This system allows your pc to comunicate also.My brother has a home automation company,I can pick his brain for some options.

Hi, TD and Bama Dude.

Sorry for the delay in replying. I was in FL at the home being built and didn't have internet access. I met with the HVAC contractor and went over the zoning/stat issues.

TD, the XL19i system is cooling 3 zones on the first floor of our home. It's about 2500sf, and the zones are divided as so:

Zone 1, the main zone is an open floorplan that is the main living area with kitchen, dining room, living room, and flamily room measuring a little over 1,000sf
Zone 2, is a Guest Suite measuring about 520sf
Zone 3, is an office, guest bedroom, and bathroom about 450sf

The house will have an unvented attic with Icynene insulation under the entire roof decking. Windows are low-e, insulated, vinyl frame. Two people live in the house.

The contractor did the required calcs.

Zoning will be the Honeywell EnviraZone system with three Honeywell VisionPRO IAQ communicating stats.

Upstairs is about 1,000sf and is the master suite consisting of exercise room, bedroom, bathroom, and walk in closet. This will be on separate 2-ton XL16i.

Regarding the rebate, I won't be using it now, since the house won't be ready for the A/C installation until August or Sept. They're running the ducts and dampers now. According to the HVAC contractor, Trane runs more rebates later in the year. I know I had to buy 803s to qualify, but for that size rebate, I would have bought at least one and installed it to get the rebate then swap it with the VisionPRO and sell the 803.

Thanks for all your help. I really appreciate you guys sharing your time and expertise.

Kevin

BTW, I don't believe I gave an important piece of information (stupid GW forum software should let you edit posts). IAE, my home is in SW Florida.

Kevin

Kevin

5 ton 19XLi
three zones
largest zone +1000 sq ft out of total 2100 sq ft

a 5 ton is way oversized for these three zones. I hope you cover this with your HVAC contractor. Perhaps, there is some missing info about the three zones on the first floor.

Hey BamaDude-what do you think about the size of the 19XLi?

Your idea about buying the 803 stat for the rebate but using the VisionPro IAQ is a good idea.

Good Luck!

Hi, TD.

My bad, the total area is 2500sf. Zone 1 is 1500sf, not 1000sf. The contractor did the manual J and they were approved by Florida energy with the county. He expects that the unit will run on the small compressor some of the time.

Is this still a concern?

Thanks,

Kevin

Kevin

I still believe a 5 ton is way oversized for three zones, a 1500 sq ft and two 500 sq ft zones. I would question your dealer very close on this issue. What does the Manual J say for the 1500 sq ft zone and the other two zones? Have you personally seen the load calculation? I would want to see it in writing and go over it with a fine tooth comb.

IMO

The Carrier Infinity in the best control I have ever had. Note: I have not owned a Trane.

With it, the hunidity control with a VS system is outstanding. And, with a 2-stage compressor, it would be even more so (we have a single stage, albeit w/ TXV).

Here is the best explanation of the "cool to dehumidiy feature I have aever read. Entire thread is at bottom link.

"No, Infinity is not the same as the VisionPro. They can both overcool up to three degrees. Everything else is different, though.

-The VP just overcools until it hits the RH setpoint. Infinity looks at the temp and humidity together and just aims for comfort. For example, if you're already two degrees below the temperature setpoint, being 2% over the RH setpoint feels fine, and it won't try to control that. I believe the logic of this tradeoff is that for each degree of overcooling, the internal (not shown to customer) RH setpoint raises by 2%. Also the amount of overcooling allowed tapers off at lower room temperatures; at a cooling setpoint of 70, no overcooling is allowed.

-The VP does not adjust blower speed *at all*. If it wants to dehumidify, it just runs plain old cooling mode until the RH setpoint is reached or the three degree limit is reached. The Infinity control is in direct digital communication with the furnace/air handler, and apparently picks a blower speed on the fly based on conditions. I have seen them run at the following CFM/ton rates: 275, 300, 325, 350, 375, 400. It may be that under some conditions they'll do 425 and 450, but you'll have to ask somebody in a drier climate about that- won't happen in Georgia. The ability to run at much lower than normal CFM/ton rates improves the amount of dehumidification relative to the amount of cooling, which does reduce the amount of overcooling that is required in the first place. While the equipment is running, it's taking care of cooling and dehumidification all at once.

How does the Infinity system keep from freezing up? Well, keep in mind that it only works with certain Carrier equipment. They know how low they can go before a freeze-up might happen. That would be tough for a third party control manufacturer to match without a sensor, because Honeywell has no idea whose equipment you're trying to control with their VisionPro. The newest Infinity equipment does have some logic to watch for a possible freeze-up, though, by watching for the change in blower operation that would happen if the coil iced over. I don't think I've ever heard of the early systems icing up, though, so clearly they know what they can get away with.

Also if you are running a low CFM/ton rate on an Infinity system, the reason you're running like that in the first place is that there is a lot of humidity to remove. Under those conditions, the coil isn't going to get unusually cold anyway, because all of the cooling is going to be going into condensing water out of the air onto the coil. Where you get into trouble with low airflow is more when the airflow is unnecessarily low- that's what gets you a coil that gets too cold and ices up.

The operation of the overcooling function does not show up on the display, though. If the setpoint is 76 and it needs to overcool for dehumidification, the setpoint will keep saying 76, but you may find that the actual temperature on the display is 74 (two degrees under setpoint) and the compressor is running anyway. If the setpoint was below what you had programmed, that's going to be because it was preparing for the next programmed period. Remember that with an Infinity system the times and temperatures you program are for when you want it to *achieve* the programmed temperature, not when you want it to start trying to get there. "

Here is a link that might be useful: Infinity Control Schedule

Thanks, TD. I'm going to be boarding a plane, now, but when I get home I'll call the dealer and see if I can get the calcs.

I'll let you know what I hear.

Kevin

TD and BamaDude.

Got the Manual J faxed to me this morning. It was done 8/20/06 as the contractor told me. Here's a synopsis:

Total Building Supply CFM: 2,656
Square ft of Room Area: 3,455
Volume (cu ft) of Cond. Space: 35,908
CFM Per Square ft.: 0.769
Square ft. Per Ton: 513
Air Turnover Rate (per hour): 4.4

Building: 5.85 Net Tons 6.73 Recommended Tons 513 sf/Ton 52.04 MBH Heating

System 1 (1st Fl - 2,427 sf): 4.47 Net Tons 5.13 Recommended Tons 474 sf/Ton 40.49 MBH Heating

System 2 (2nd Fl - 1,028 sf): 1.38 Net Tons 1.61 Recommended Tons 640 sf/Ton 11.55 MBH Heating
-----------------------------------------------------------

System 1 is 5-ton XL19i and System 2 is 2-ton XL16i. Both use Trane variable-speed air handlers.

The HVAC contractor said System 1 should run on the 2.5 ton compressor 85% of the time.

Should I still be concerned, or has he done his homework?

Thanks,

Kevin

Kevin

Not trying to be difficult only helpful. The information provided is incomplete.

Here is the bottom line question.

What are the cooling BTUs required for upstairs along with the cooling BTUs for each of the three zones downstairs. And yes, I still believe a 5 ton is oversized. Have you checked your dealers's knowledge and experience with zoning?

IMO

Hi, TD.

I appreciate all your help. I don't think you're being difficult. I want to give you all the information you need.

I uploaded my Manual J to a website I have. The names have been erased to protect the innocent. :-)

The dealer sounded as if he was knowledgeable about zoning and the Icynene insualation and conditioned attic space. Looking at the Manual J, though, I see it only shows one zone for both systems. System 1 will have three zones, so I don't know if that affects the calculations.

Does it matter that this is a two-comprssor system and will only use the 5-ton when needed?

Thanks,

Kevin

Here is a link that might be useful: Manual J

Hi, TD.

Did you get a chance to look at the Manual J?

Thanks,

Kevin

Kevin

I did see your Man J but was hoping someone else would respond to the 5 ton XL19i system recommended for your ground floor with three separate zoning areas. You have apprx 30 KBTUs cooling for the main living area with balance for the two bedrooms. Yes, I still say a 5 ton is oversized and would suggest a 4 ton at the max.

My opinion.

Hi, TD.

Thanks for taking a look at the Man J. I definitely take your opinion to heart and appreciate you expressing it. Does it make a difference that the 19i has two compressors and will only run on the 5-ton when needed?

If the Manual J says 5-ton, and my contractor feels it correct, how do I convince him that he should install 4-ton?

Kevin

kevin

The Man J that you provided if accurate shows 45,775 BTUs of cooling required for ground floor. A 5 ton XL19i provides apprx 60,000 BTUs of cooling. That is approx 33% difference between 45,775 on Man J and apprx 60,000 BTUs of cooling a 5 ton produces)-12,000 BTUs/ton. For me that raises a question of sizeing. Yes, a two stg is somewhat forgiving on oversizing but this can hurt you on operating cost,comfort/dehumidification, and shortcycling. Make your dealer justify his cooling load calculation with his recommended 5 ton size. If this was my home and a superior HVAC was important, then I would run these numbers by a disinterested third party with experience in residential HVAC zoning.

My opinion.

XL19i WEATHERTRON HEAT PUMP (R22 Refrigerant)
Model Nominal
Cooling Capacity (BTUH) Nominal Tons
Height
(in.) Width
(in.) Depth
(in.)
2TWZ9030B 30,000 2.5 50 37 34
2TWZ9036B 36,000 3.0 50 37 34
2TWZ9048B 48,000 4.0 50 37 34
2TWZ9060B 60,000 5.0 50 37 34

TD,

Thanks, this gives me some more information to present. I see the 45,775. What is the [B]Ventilation[/B] and [B]AED Excursion[/B] that's referenced, bringing the total to 53,642?

I don't see on the Manual J where there's anything showing a factor for the Icynene insulation, which is supposed to allow me to reduce the sizing of HVAC, or the Low-E, argon-insulated windows we're using. I'd imagine they'd have an impact on the recommended size. Also, my wife and I don't use A/C as much as other people. The house is on the water and gets a really good breeze off the river. That, coupled with ceiling fans in all rooms, is good enough for us except for very hot, humid weather, which of course is all Summer in SW Florida. When we do run A/C, we usually don't set it lower than 78, and never lower than 76. As long as the humidity is lowered to a comfortable range, 76 to 78 is perfect for us. If I understand the role of sizing, a too large compressor will not run long enough to dehumdify properly, and with a thermostat at 78 it's possible we'll never get the humidity to a comfortable level. On the first floor, the 520sf Guest Suite will rarely be occupied, so we will have the suite closed off and the thermostat set to 80 to 82. The two other zones, totaling 2000sf, will be used every day and will have stats at 76 to 78, so normally we'll be cooling 2000sf. Should this be factored in the Man J, too?

They're just running the ducts and the zoning dampers now. The compressors won't be installed until at least August, so I have time to make the right decision. I'm not sure when they put the two air handlers in. With the 4-ton XL 19i would the air handler be the same as the 5-ton? If so, then I don't have to worry about that in case those go in earlier. We're moving in June and renting the house next to our build, and I'd rather go over all this face to face instead of email. If it can't wait, I'll fly down and have a meeting.

I agree with you that superior HVAC is very important, and I don't want to make an error. Where would be the best place to find an independent party to review the calcs, and what do I need to supply to get accurate info?

Thanks again for everything.

Kevin

Hi, TD.

One more question about the 4-ton. Will the 2-ton small compressor on the XL 19i 4-ton be adequate for most of my cooling? Part of my contractor's argument for the 5-ton is that it will run on the 2.5-ton compressor most of the time.

Thanks,

Kevin

Kevin

For starters, keep in mind a Man J is only as good as the accuracy of the information inputted. your post raises even more questions as to sizing with the insulation qualities of your new home as well as your temperature thermostat settings for the ground floor zones. With that said, you don't have much time because ductwork is also sized according to amount of CFMs which is determined by your equipment size.

Air handlers are matched to the outside condenser for the best efficiency.

If you want an independent opinion, I suggest you call your electric utility who usually has an HVAC residential expert on staff or perhaps they can provide some names as possible resources to review your new home's HVAC requirements.

I'll call the electric company now and check on it. I'll let you know how I make out.

Thanks,

Kevin