Zoning & Outdoor sensor

I will be installing a new geothermal heat pump later this year and have received a lot of good information on what to be aware of from this site. I have a few items that I am trying to find additional information on and would like to obtain opinions on these topics. For a little background the style of house is a Cape Cod style. The location of the installation will be in Pennsylvania. The unit to be installed will most likely be a Climatemaster Tranquility, closed loop system.

1) I interested in exploring zoning the 2nd floor separately from 1st floor. In addition, I might want to zone the back of the 1st floor separately as well due to solar heat gain. In looking at the controls that Climatemaster offers it does not appear that they have a way to incorporate zoning into the system. Therefore, it appears that a 3rd party controls package would be required. What, if any control packages can you recommend? Is it worth zoning the ductwork? Are there downfalls to zoning?
2) I have noticed that some of the thermostats offer the ability to wire in an external temperature sensor. I know that this is beneficial for boiler applications where the boiler will heat the water to a temperature based on the heating load required while factoring in the outdoor temperature. Does this external sensor provide a benefit for a 2 stage GSHP?

Thank you for your help.

Arzel Zoning here in Cleveland.

I suppose outdoor reset could be used on a geo system, but why the heat transfer ocurrs in the yard not outdoors.

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Originally Posted by EricK

I will be installing a new geothermal heat pump later this year and have received a lot of good information on what to be aware of from this site. I have a few items that I am trying to find additional information on and would like to obtain opinions on these topics. For a little background the style of house is a Cape Cod style. The location of the installation will be in Pennsylvania. The unit to be installed will most likely be a Climatemaster Tranquility, closed loop system.

1) I interested in exploring zoning the 2nd floor separately from 1st floor. In addition, I might want to zone the back of the 1st floor separately as well due to solar heat gain. In looking at the controls that Climatemaster offers it does not appear that they have a way to incorporate zoning into the system. Therefore, it appears that a 3rd party controls package would be required. What, if any control packages can you recommend? Is it worth zoning the ductwork? Are there downfalls to zoning?
2) I have noticed that some of the thermostats offer the ability to wire in an external temperature sensor. I know that this is beneficial for boiler applications where the boiler will heat the water to a temperature based on the heating load required while factoring in the outdoor temperature. Does this external sensor provide a benefit for a 2 stage GSHP?

Thank you for your help.

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I have a 2 zone configuration with my installation. I have a WaterFurnace and they have their own zoning unit. My two zones are 1st floor and 2nd floor. I have been very happy with the system. The only discovery I made this winter with the WF unit is if all zones are not calling for a certain level of heat the emergency heat will never be invoked. I had the upstairs set to 70 and the downstairs set to 75. I woke up one very cold morning (-18) and we were 70 upstairs but 73 downstairs. The downstairs tstat was making a stage2+ call and was expecting the electric coils to be running, but they were not. I thought something was wrong but since the system felt it could heat one zone to the desired level it had sufficent capacity to heat all zones.

As a refrigeration system, a certain amount of airflow is required for your geo system to work well. Too often I see poorly designed systems that cost folks more than they save. I also am not a fan of doing electronically what can be done with duct work. Ask your contractor his opinion of how best to meet your goals, and ask for refrences that specifically have zoned systems if that's what you install.
Good Luck,
J

I have a 3 zone system with a WaterFurnace Envision unit and a WF supplied proprietary zone controller.

I've learned that air distribution zoning is tricky. Thus, to avoid performance problems and later repair expenses due to premature failure of parts, you really need an exceptionally skilled installer who can properly size the equipment / outside heat exchanger, and design the air distribution system (Manual D - duct routing, duct sizing, air flow volumes & velocities, registers & proper placement, return air system, and on and on ...)

And zoning gets even more difficult with today's ECM variable speed motors because the design needs to be done without a traditional bypass damper.

If you're looking at units with variable speed ECM blower motors, I urge you to look at the manufacurer's zone control products versus a 3rd party, to make the design as straight forward as possible.

Best regards,

Bill

Zones save some $ and can ( depending on how you use them ) decrease the load and size of equipment ( nothing dramatic but can make the difference in some cases to the point where a cust. can go with 1 system instead of 2 , then its huge ) The ductwork issue can be easly addressed by a pro by slight oversizing / dump zone. but I would get iffy around 3 and never 4 for air flow issues . ODT sensors are my preference for controlling aux. heat ( combined with a time delay ) because I use beleive and encourage the use of setbacks except when we get close to design temps. just an opinion
http://www.broudyprecision.com/PDF's...ections_08.pdf
This is the honeywell product line we use and the only one I can recomend for doing what I talked about. As is true with anything buy a product with easily obtained parts .

Thank you all for the replies and info. I guess I have some more research to do.

geo_fan
I believe my line of thinking was the same as what you described with respect to the out door sensor. I would assume, that the controls would take a look at the indoor vs outdoor temp to decide which stage (or aux heat) would be required during the recovery phase. As far as the "dump zone" that you described, I have also read about using a "by-pass" where the supply is connected to the return plenum using either a barometric damper or in some cases electronically controlled. Can/should this be installed with an EMC motor? Also, the Honeywell systems that you typically use, does it control the EMC motor directly? In other words will it scale back the speed of the motor depending on the number of zones calling for heat/cooling?

Thanks again,

The zone board does/can stage based on % of zones calling or ODT
the ODT sensor does what your talking about for humidifiers to prevent condensation on windows but for equipment control it is used to lock out stages at preset /adjustable balance points ( its also wireless which is nice for retro )
I have yet to explore ALL the advanced configuration options but have yet to find a control design I couldn't achieve ( once or twice I have had to add a rib relay or time delay )

On dumping
bypass set ups can do decrease eff of the system by how much ? how much are you dumping , if there is no acceptable space to dump air and not much is being dumped its ok , but you can see where my preference is
Yes you can avoid dumping all together if you set up so a single zone wont see anymore the 1st stage ( which may not be possible depending on load or desired recovery time )
ECM motors turn the black and white of zone design into shades of gray . Maybe its just me but ducts should be designed as if its a PSC and for worst case loads , then let the ecm smooth it all out

I saw outdoor sensor as outdoor temperature reset.

Reset is something we use in hydronics all the time to control what temperature the system runs at through the season.

I do use ODT to control what runs when. I use it to "make the home owner wait" for the system to do it's thing, before bringing in the big expensive guns.

I am only humane.

Take a look at the Honeywell TZ4 zone controller and the touch screen IAQ thermostats. It controls up to 4 zones with the main controller and is expandable. The thermostats display indoor and outdoor temperarture and the system will display humidity in each zone. Zone 1 can control humidity through the TZ4. The TZ4 will operate standard zone damper motors. Works fine with a FHP GO series 2 stage system.