I'm a long time lurker and only a recent register, but I have found some great information on this site already. So, my question is regarding zoning an upstairs and using the Climadry option that can be optioned with the Tranquility 27 model. I live in Virginia where the humidity level can be relatively high with cooler weather, and am really turned on to being able to install a humidistat for my new 3 ton unit I am installing upstairs in my two story house. My question is, I will be zoning the upstairs into three separate zones--master bath and bed, guest bedrooms and bath, and finally the FROG. My question is in regards to the ability to control humidity levels from multiple thermostats. Right now I am looking at installing the following: - Climatemaster 27 3 ton w/ Climadry - Honeywell YTHX9421R5069 <--Prestige Thermostat, 2 duct sensors, exterior wireless sensor, EIM module. - THM4000R100 <--Wireless outdoor sensor - HZ432K <-- Zone control My question is, would I be able to connect this in such a way that I can install two additional thermostats with built in humidistats in order to call for the dehumidification independently, or is it only possible to use the one Prestige model and hook that up directly to control the humidity level. Thanks for any/all help that you can provide.

no one? Is there additional information that I need to provide to help out?

Sorry, but Climadry is not something that I have ever seen or used and is not a topic that is talked much about here?

I think Climadry is under discussion at Geoexchange. From what I've been able to gather it is a tricky, perhaps poorly-documented option difficult to get right.

I'm in Florida, home of humidity. I do dehu stats without Climadry (Honeywell 8000-something 1097) that can reduce humidity by both slowing the blower and drop drybulb temperature by 2-3 degrees.

With a common return all air is mixed, so multiple humidity control points may be overkill. That said, confronted with the requirement I'd let the largest, most centrally located zone stat reduce CFM per ton and the others drop drybulb setpoint as needed for humidity.

I advocate a multi-tiered approach against humidity; indeed active dehumidification is the last defense. Start the battle early by:

1) Controlling internal sources of humidity - operate good, quiet bath fans on timers or motion sensors, not just when the shower light is on. Try to avoid installing / cooking with a gas range. Put large houseplants outside in summer. If possible, eject large dogs and adult children for the summer as well - all are sources of excess humidity.

2) Control external sources of humidity, bulk water leaks, air infiltration. Invest in blower door testing, air sealing, perhaps even spray foam insulation backed up by smoke testing.

3) Size the unit properly - err on the low side. Are you absolutlely certain 3 tons is needed for your 2nd story? If two will do, dehu will improve. Most of my clients find that if we get humidity down to the 40s, cooling thermostat setpoint can be as high as 78. Sizing is crucial for humidity control.

4) Install a 2 stage system (Tranq 27 is two stage, and you'll need 2nd stage to support 3 zones)

5) Install humidistats as described.

I have serviced a Climadry and agree with Curt there is not adequate manufacturer support on the product.
I have so many questions about your sizing and zoning intents I can't even begin to consider dehumi strategies at this point.
What is the loss gain calc for each of the upstairs zones.
I will tell you one thing I am convinced of; an oversized heat pump with Climadry can't help but to cool.

Thanks guys for the input. I had several Geothermal companies come and give me a quote, and when essentially none of them wanted to do a proper Manual J heating load, I decided to start working the calculations myself. I work as an electrical engineer for a Federal agency, and I have some mechanical engineers that I was going to run my calculations through prior to making my final load determination. I'm also just taking into account what the majority of all the companies that came out determined that I needed a 2.5 ton unit--and since Tranquility 27 units only come in full tonnage, they recommended going with the 3 ton unit. They justified that this would still work since the unit features 2-stages. They all said (had 5 different companies come by) that it would run in the first stage for the majority of the time, and would have the additional capacity during those "heavy cooling days."

The current unit is a 20 year old Carrier 2-ton split. During 90+ days the unit will run nearly non-stop (18+ hours) until sensible cooling point has been reached. When it was 100+ outside for a few days, the unit could not keep the upstairs cooler than 82. I recently had it serviced and they said they had to add two pounds, but the evaporator was brand new. The house is as old as the original unit. It is approximately 1600 SF on the upstairs that includes a FROG, three bedrooms, and two baths. The master has a domed skylight that puts out plenty of heat. All the windows are original, double pane, double hung, with wooden construction. The attic hass R30 fiberglass and batt insulation that seems relatively well covered. Three of the four outer walls are all vinyl, with the remaining wall constructed with a brick facade. The downstairs unit was replaced about a year ago from the previous owner (we just bought this place in February) with a 3 ton Goodman gaspack.

My current plans are to have 6 wells drilled at 200ft with a spacing of around 12-14'. The driller has been installing geo wells for a long time around here and is doing a reverse return setup. I am having all six wells drilled so that I can replace the Goodman unit sometime next year. I figured that this would help to add additional capacity since the different levels will be taxed more heavily during different times of the year--the upstairs needs more cooling in summer, and downstairs will require additional heating in winter.

It sounds like everyone here is recommending NOT to go with Climadry. What really drew me to this feature was the ability to maintain dehumidification with an even temperature.. ie, set thermostat to 76 and even though it is only 78 outside, the Climadry would both cool, then reheat the air in order to maintain the set point. It also appears to drop the blower speed by 25% to allow additional moisture to be extracted from air.

My biggest question was how I would be able to control this dehumidification function of the unit when I zone the upstairs ductwork. I'm beginning to believe that I will have to just rely on one thermostat that is centrally l located in order to provide dehumidification based on the de-humidistat readings and allow the other two to only base the temperature on sensible cooling for that area. In order to allow the wife to be able to plan for the day, I was also hoping to allow for an external humidistat and temperature values to be displayed on the thermostat.

I hope that this helps answer some of the questions. I am very thankful for any and all that can provide additional input based off of the above information--I know that there are a lot of people out there that have had the pleasure of seeing what works, and doesn't work, when installed in the field. My basis of engineering is solely built up around calculations, forums such as this, and my mechanical counterparts. Thanks in advance!

Okay, so far you are designing byu conjecture. Your 2 ton didn't keep up when it was 100* but it wasn't properly charged.
My concerns are
1) you don't know or care to start with btu load
2) you want 3 zones on what will likely be an oversized unit
3) you have installers that don't do the fundamentals and you are exploring a complicated feature
This is a recipe for too much heat pump in too little duct work- noisey operation, dissatisfaction, complaints......

1) if your current unit is working properly, it is a more accurate source of total load data than a manual J.
2) but - get a blower door test and seal things up better first
3) avoid zones if possible. Adjusting ducts (supply and return) should get you close.
4) consider conventional dehumidifiers
5) consult an expert before you spend all that money on wells, etc.
6) space wells further apart than that

Yes, so far I have not been able to complete the load calculations. I am in the process of working that and will post here once I have that completed. I plan to have that all worked out in the next few days.

To clarify things, the existing unit was recharged PRIOR to those extremely hot days. Right now, when the outside temperature is 85, the temperature drop from the ambient, to the supply, is only about 10-12 degrees. Once the outside temperature gets into the low to mid 90’s, the temperature drop is less than 5 degrees. The unit is 20 years old and I feel that I am working on borrowed time so I feel more prone to expedite the installation process.

The driller that I have gone with for the wells has been working in the area for 36 years. He has drilled several wells in my neighborhood and he says that they all have a lot of sand and water once you get down less than 15 feet. Accodring to these factors, he says that the wells can be spaced closer together since the conduction of the earth is high. Is this untrue? I thought that the information I read indicated that sandy, moist soil was one of the better soil for conduction.

I'm not trying to contradict anything that is bing suggested, I guess that I'm using this as a sounding board to try and work a dialogue with other people out there that have had more experience.

joe.ami--why are you opposed to zoning? It seems that all of the literature that I've read is for zoning. All of the spaces that are going to be zoned will be upstairs on the same level, so I'm not sure how much adjusting the ducts would help since the downstairs is on a totally separate unit.

I have decided to not go with the Climadry since it is also a special order item.

I'll update more later to some of the responses. Thanks for the help guys.

Typically, it costs little to nothing to space the wells at ~20' - so why risk reduced performance from the wells interfering with each other? Wet sand is good - use that to reduce the amount of drilling needed. Software such as "Ground Loop Design" is recommended.

I think that the intent was to keep the ground loops equadistant from each other to provide equal loading for each ground loop. Each ground loop is approximately 12-14 feet apart from the one adjacent. Is this a requirement, or can they be spread around more? I'm having them install this in my front yard that has a couple of huge oak trees located on a center island--which I believe he is trying to avoid. Also, on the opposite side of the front yard is where all the utilities are coming into the house. There might be a way to move closer to the street with the other ground loops, but again, I thought he was trying to be equadistant. I can ask him next time that I speak with thim.

Again, I'm not trying to contradict, I'm just asking the questions to become more educated myself.

Ten comments:

1. I would not drill the holes 12-14' apart.  In the Dallas area 15' is considered a minimum.  When my borehole field was drilled, I asked for 20' and had no push-back from a very well respected driller.

2. Air zoning is exceptionally tricky to get it done well.  And incredibly so if it's a retrofit job.  The size of the supply ducts must be matched to the air blower, and with the assumption that only one tstat is calling for air.  Return ducts are critical - if you don't presently have them to each bedroom then you'll need them installed (or cut a vent in each bedroom door).  Adequately sized return ducts will make or break the project's effectiveness.  Three small bedroom zones on one unit, regardless of size, requires some particular design expertise.  Some kind of air hood instrument is very helpful to get blower speeds, register openings adjusted, and damper motors set.  Your proposed zoning will probably require all 3 damper motors to not close completely.  The domed skylight in one of the bedrooms will further increase the complexity of the design.

3. More on air zoning: your project is doable (3 small zones on one unit), but it's going to require someone who really has extensive expertise in challenging zoning efforts.  Someone who knows air distribution backwards and forwards.

4. Even more on air zoing: use willingness to do a Manual D as one of the key criteria in your contractor selection process.  You may have to pay up front for the Manual D if you don't want to commit to the overall project first.  Few, if any, reputable contractors capable of doing really good Manual Ds will do them without a project contract first, or, without separate payment first.

5. I would not 'drill now and install later.'  This invites one trade blaming the other if things don't work.  Set your project up so that there's one person/company accountable for end performance.

6. The size and type of unit will dramatically affect success or failure of the air zoning as proposed.  I think it will be a 'crap shoot' without a carefully prepared Manual J first, and then a Manual S.

7. The tighter you make all the rooms upstairs, the more difficult it will be to get the zoning to work.  Remember, a certain minimum volume of air must always be going through the evap coil, regardless of how few tstats are calling for air.  And this air has to go somewhere.

8. To allow yourself opportunity to be maximally efficient, if tightest possible structure is also a signficant requirement along with zoning that works for your situation, you'll need to consider one of the new technology variable speed compressor units, like the Envision 7.  Doubt this is the lowest cost of ownership option, though.

9. Do not proceed with a system design that uses a variable speed ECM blower motor and additionally calls for a bypass duct from supply to return.  In your situation particularly, this is a recipe for a poor performing system, up to and including icing up the evap coil in cooling mode, and overheating it in heating mode.

10. Overall, your project is doable, and can be done to meet your requirements.  But expertise needed and expense will be on the high side.  And the fact that you already have a virtually brand new unit for the ground level doesn't put ROI in your favor when looking at the investment for geothermal.  Spreading the cost of the borehole field across only half of the structure's heating/cooling needs probably makes geo an expensive option.

Hope this helps.

Best regards,

Bill

The spacing on the ground loops does not have to be equidistant.   If some are 15 feet and some are 20 feet there is no harm.  In your case,  I would have the driller space them as far apart as your conditions allow.

OK, I will agree that if you size ducts and adjust dampers such that a zoned system always has adequate flow (even when only the smallest zone is on) and you have balanced electric dampers on both supply and returns (so you aren't pressurizing rooms), then it could be a nice to have. I suspect that very few residential installers have the tools and knowledge to get it right - try asking them what the differential pressure in pascals is between each room and outdoors, with and without the hvac fan running.

a0128958- first off, thank you very much for your input. I will try to address some of your comments later this evening when I have more time to write them up. Two comments that I would ask you elaborate on for my edification are number 2 and 9.

2.) You suggest that I have a return in each bedroom in order to properly zone. I intended to utilize the properly sized gap at the bottom of the door to prevent pressurization of the rooms which will dump out into the common hallway where the return for that zone will be. Will this design approach be sufficient, or do you still see some additional problems that I should address before proceeding? As mentioned before, I will be working with the Manual J, Manual D, Manual T, and Manual S references in order to work out the appropriate sizing.

9.) You indicate that a return damper that dumps the excess supply back into the return is a bad idea if I use an ECM motor--can you elaborate a little on why this is the case? The model that I was planning on going with does in fact use the ECM motor and I was planning on using that type of dump configuration for the new ductwork. Is there another alternative to this method? I don't have any high, or open, areas that I can just dump everything to--unless you counted the FROG as being an area that would be appropriate for this since it is one of the most open areas with valuted ceilings etc.


geodean - Thanks for the input. I'll speak with the driller and see if he would be willing to increase the distance of the ground loops. There is additional realestate out there, and I'm sure that he was just trying to do this in order to keep his costs down. I figured that my yard is going to be tore up one way or the other, so I might as well get it installed with a little more confidence that the distance won't pose any problem.

jomr - Until the attic cools down, I will be utilize the existing ductwork that is in place. I am in the process of designing an entirely new duct system in order to work with the 3 zones. I had planned on using a a bypass damper that went from the supply to the return when only the smallest of the three zones was being called until a0128958 called out that this is a bad idea.

Posted By jonr on 14 Aug 2012 11:04 AM
... I suspect that very few residential installers have the tools and knowledge to get it right - try asking them what the differential pressure in pascals is between each room and outdoors, with and without the hvac fan running.

At least in the Dallas area, this would indeed be the clear problem - finding someone willing to do this at a residential level.  And even so, properly charged for, it's going to be expensive.

Further, the new unit for the ground floor really complicates the economic analysis.  Rarely, if ever, does it make economic sense to remove a perfectly functioning system to put in a more efficient system.  The only thing that makes even less sense to me is adding a costly system for just half of a structure.

Instead, if were me, I'd toss out the alternative for a geothermal system for the upper level, and instead figure out what the economics are with:
1.) substantially tightening up the entire structure
2.) substantially reducing the heat gain/loss of the structure (ranging from lighting to appropriate insulation levels to using radiant barrier to window shading to external tree provided shade considerations)
4.) removing the 20-year old upper floor HVAC unit
5.) doing some kind of two-zone upper versus lower floor zoning, well designed

Still a signficant effort, done well and done properly, but, I'll bet the economics of the effort are much improved over putting in a geo system just for the upper level.  And I'll bet the odds of having good RH are significantly favorable.

In fact, if it were me, my step 0 would be to get some instrumentation installed to understand the current situation and provide quality data for meaningful economic analysis: power consumptions, lower floor new A/C system's actual performance, room temperatures.

And then in between Step 0 and Step 1 above, I'd probably figure how best to get a good, solid, accurate Manual J for the entire structure, room by room.  I'd do it by either hiring it out to someone with good reputation doing it at a reasonable price, or, do it myself with considerable study and using a few hundred dollar s/w package.

Best regards,

Bill

I intended to utilize the properly sized gap at the bottom of the door to prevent pressurization of the rooms

I recently read a study that showed that outside air infiltration is commonly 5x higher when the hvac is running than when it is off. It didn't look at the causes, but my guess is that under door returns, unbalanced supply/returns and similar shortcuts are why. A good ACH50 is only part of the story - the rest is reducing pressures (and duct leaks).

Opposed to zoning? Not when done right. I simply object to the near universal notion that it is the only way to achieve balance (when more often good duct design is all that's lacking).
You have a system that is almost adequate now. You are discussing adding 50% to that capacity and cutting the work load in three. So far does not smack of positive outcome.

What would work would be a truely variable system.As I read this it occurs to me if you get the load down to 2 tons or less and load share with 3 zones, a variable furnace and AC which should be far cheaper may cost little more to run making pay back on the geo very long term indeed.
I get that the tax credit won't help with conventional gear, so you will really have to do some number crunching.
If you do put in wells I would be tempted to put in enough to cover the lower level as well as tax credits may not be around when that equipment is due for replacement.