Compare Honeywell TH8321 U versus R model thermostats


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Old 08-17-14, 08:51 AM
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Compare Honeywell TH8321 U versus R model thermostats

I live in the Tampa Bay area of Florida and have been living with ground source heat pumps for about 4 years. All but 1 problem have been with the closed ground loop, and were quickly addressed by my contractor. The loop was originally sized with a pool heat pump in mind, and I have recently added that unit as well. A couple of months in the spring we need to cool the house, but heat the pool at the same time (pretty sweet to get that synergy).

My house units are Waterfurnace Envision series, a 3 ton and a 2 ton for my 3,000 sq ft home. These are variable speed, 2 stage heat and 2 stage cool with no back up emergency strip heating. Both units have desuperheaters and soft start electronics. The original thermostats are both Honeywell TH8321U models, and I do use the dehumidifier feature which I think works well for us. The one thing I desired but did not get with this install was remote temperature sensing / averaging. The house zones are not really well suited for a single sensing location but the Honeywell wired sensors for the TH8321U had a strange requirement as to number of sensors (due to the simple use of thyristors?).

What I would like to know is: "Would the redlink enabled version of this thermostat, TH8321R, work the same with my ground source heat pumps as the TH8321U model, and would the associated remote wireless sensor, C7189R, have any special requirements? Any drawbacks, or other advice on using the TH8321R and / or the C7189R? I have reasonable DIY skills, should I be able to install and program the new units myself?"

My cost to change the thermostats is somewhat mitigated by the fact I can use the existing TH8321U units to improve the control of Trane packaged air source heat pumps operating in my family's homes in north central Florida (Jacksonville area).
 
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Old 08-17-14, 09:14 AM
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"Would the redlink enabled version of this thermostat, TH8321R, work the same with my ground source heat pumps as the TH8321U model
Yes,the TH8321R will support your application. It is almost the same thermostat with more terminals and the opportunity to add more controls to your system. It will support wireless indoor sensors and averaging.

The internet gateway and an outdoor sensor would be some additional controls that you might consider in the future. One Gateway will support up to 4 thermostats.

The addition of an EIM in the future would allow more sensors to be installed to monitor your system.
 
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Old 08-17-14, 10:41 AM
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Thanks Houston. The addition of the Gateway is something I have thought might be nice, when the funds become available. Will check out what I can do with the EIM as well. The quick response is much appreciated. Will post the outcome when I get the task accomplished.
 
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Old 08-17-14, 11:06 AM
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I have a return air duct sensor, a supply air duct sensor, a float switch and a pressure switch connected to my EIM. The pressure switch will trip if my mechanical filter gets too dirty and send an email to my phone. If the delta tee gets out of the range that I configured or water gets in my secondary pan I would also get an email.

The EIM also supports more dry contacts than the stat alone.
I don't have a humidifier, dehumidifier or variable speed furnace and 2 stage cooling unit to take advantage of the dry contacts.
 
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Old 08-17-14, 09:05 PM
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All good things to know asap with those sensors. My complaint with the configuration I have now is that I have to go to each Envision unit and look
at the indicator lights to see if and what problem the system is reporting,
with no feedback on the thermostat. I understand newer Envision models don't have the indicators, just a code read out requiring a device that few homeowners would buy (like the code readout mechanics use on modern cars). I do not use the contacts for a separate dehumidifier, but rather use the dehumidification feature that the thermostat implements by running the system in cool, up to 3 degrees below the set point (essentially the heat pump is my whole house dehumidifier, and it works fairly well in that mode). There are some models which appear in the literature to only use the contacts and not dehumidify using the controlled AC itself. In this area of Florida I have no use for a humidifier.

For those interested, today I did found a Honeywell brochure that has a table indicating the features that are included in programmable and non programmable Honeywell thermostats (with one column showing the wiring connections available). It also notes which models that support humidification, dehumidification and ventilation require an EIM to implement those features.
 
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Old 08-18-14, 05:12 AM
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I miss the onboard diagnostic LED's.
We use the "MUI tool" for diagnostics now. It offers a few more features than the old LED's.

The 7 series requires a different diagnostic device. The "A tool" used on it is also used to configure settings that were done with dip switches on the 5 series. So now homeowners need 2 devices if they own 5 series and 7 series geo heat pumps.
 
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Old 08-23-14, 08:05 AM
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Received my Honeywell TH8321R1001 today. Time to start installation. My plan is to install this on the 2 ton Waterfurnance heat pump in my home and if successful purchase another for the 3 ton Waterfurnace heat pump in my home. I currently have TH8321U1097 Honeywell thermostats, with wired connections to the heat pumps.

Question 1: I assume I can scroll through the original installation values (based on ISU table) for the TH8321U1097 and record those values. Should I start set up with the same values? Or maybe I should publish the values here for comment? Once the new unit is set up I see I can download its values for use if I get a second TH8321R1001.

Any words of wisdom before I get started? It is a hot day, but even if I take a long time I think the 3 ton unit can keep the temperature reasonable.
 
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Old 08-23-14, 09:25 AM
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What is the model number of your Geo unit?
Posting the configuration settings of your existing thermostats would be a good idea.
 
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Old 08-23-14, 01:13 PM
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Waterfurnace heat pumps servicing 3,000 sq ft in Palm Harbor, FL
2 ton NDV026B14INTR w Intellistart and desuperheater, no auxiliary heat strips
3 ton NDH038A14INER w Intellistart and desuperheater, no auxiliary heat strips
Installer setup values on TH8321U1097 thermostat for 2 ton unit (no changes since original install)
0120 20
0130 14
0140 8
0150 23
0160 4
0165 0
0170 11
0173 1
0190 0
0220 3
0280 1
0300 1
0310 6
0320 0
0330 2
0340 0
0371 0
0380 1
0383 3
0390 0
0500 4
0502 0
0510 0
0520 0
0530 1
0540 2
0580 4
0600 90
0610 50
0640 12
0650 0
0660 0
0670 0
0680 2
0690 2
0700 0
0701 0
0710 0
 
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Old 08-23-14, 04:02 PM
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http://www.waterfurnace.com/literatu...n/SC1020AN.pdf

http://www.ntsupply.com/files/produc...om=160,-87,409

I would have been surprised to see electric heat strips on a 2 stage Geo unit in Florida. We rarely have heat strips here either.

The new thermostat doesn't use configuration codes. It's multiple choice so no code book is required. You just need to know what the old codes were set to.
 
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Old 08-24-14, 07:05 AM
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Thank you for the links to Waterfurnace and thermostat information.

Reviewing the current thermostat settings I have questions about dehumidification functions. I have code 0380 set to 1 indicating that I want to "Dehumidify with air conditioner" then code 0383 set to 3 allowing the maximum over cooling to be 3 degrees. My questions relate to code 0390 "Dehumidification Away Mode" which on my thermostat is set to 0, meaning this mode is not in effect.

What does "Dehumidification Away" mode do differently than "Dehumidify with air conditioner"? If this function is turned on how do the values in codes 0391 through 0394 effect the values entered on the thermostat for humidity set point or low and high temp set points? Based on the thermostats operating manual page 15 I see that the "Dehumidification Away" mode is activated by pressing the hold key three times. Does that then override the settings entered on the thermostat? With "Dehumidifcation Away" activated (hold pressed 3 times) is the over cooling limit ignored or still applied?

Is there an advantage to using "Dehumidification Away" hold as opposed to "Vacation Hold" with "Dehumidify with air conditioner" and set points the same as in codes 0391 to 0394? I often use "Permanent Hold" rather than "Vacation Hold" for a number of reasons, such as allowing my son to change the temperature set points when he checks on our home, changing them back when he leaves, and never having to deal with "vacation hold" days etc. So I would like to fully understand how all the functions interact.

Maybe others can be helped by a tutorial in this arena as well.
 
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Old 08-24-14, 08:07 AM
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Refer to page 11 in the manual.
Dehumidify with air conditioning will turn on cooling to dehumidify and can overshoot the cooling setpoint by up to 3 degrees to accomplish this.

If you are in Away mode the humidity setpoint can turn on cooling to get it below 65% (or your setpoint if you change it from factory setting)


Dehumidification Away Mode
(Setup Functions 0390-0394): This feature is useful for homes in southern
climates. It allows humidity control when the the home is unoccupied for long periods during the hot/humid
season. You can control temperature (Function 0393) and dehumidification (Function 0394) while away. You
can control humidity with a dehumidifier or a cooling system (Function 0379). If a cooling system is used,
humidity is controlled by cooling indoor air to the Low Limit Temperature (Function 0392). When the desired
humidity is reached, the system will maintain the temperature you select in Function 0393
If you get the gateway and wish to control the system from your phone you may want to avoid Vacation mode. I have had a customer tell me that they cannot adjust setpoints from their phone when the stat is in Vacation mode with the older Prestige thermostat. This may also be the case with this thermostat.
 
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Old 08-24-14, 11:16 AM
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I have to admit I previously read page 11 too quickly. Thanks, I've reread the section on Dehumidification Away. The information I wanted is there, same process as described in the manual for the Vision Pro with Redlink.

Since the Dehumidification Away mode will cool to the setup low temperature or until the humidity set point is reached, I need to decide if that's want I want to do or not use that function and rely on just the 3 degree over cooling. A choice of better probability of hitting desired humidity at cost of longer run time, versus limited run time but maybe missing the humidity mark. Given the high cost of mold / mildew remediation I will likely choose the away mode.

A new question arises; in Dehumidification Away Mode, what happens if "System" was set to AUTO on the thermostat? (Sometime with the family property the houses are vacant over a period when there is a need to switch between cooling and heating, or vice versa.
 
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Old 08-24-14, 11:56 AM
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I have seen indoor humidity drop into the low teens in heat mode.
Humidifiers can be installed to add humidity in heat mode.

It seems very unlikely that a demand for dehumidification will present itself in heat mode.

You are welcome to contact the Honeywell Support line with this question. I would be interested in their response.
 

Last edited by Houston204; 08-24-14 at 12:37 PM.
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Old 08-24-14, 01:58 PM
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Call me inpatient. I just changed my TH8321U1097 to allow Dehumidification Away Mode. Then with the thermostat "SYSTEM" set to AUTO I hit the "Hold" button 3 times. Display now shows SYSTEM = COOL, INSIDE = 78 (which is the current inside temperature), SET TO = 84 (which is what I set 0393 to be), shows the phrase "Dehumidifier" and 55% (which is what I set 0394 to be), also shows the phrase "Permanent Hold". Pressing the "MORE" button yields a display with "Inside 50%" with "Humidity" in text below the number. This is an appropriate value for the current humidity at the thermostat location. System is not running at this time, which based on the parameters and values is correct.

Pressing the "CANCEL" button removed the "Permanent Hold" but left the System set to COOL, it did not return to the AUTO value I started with. Cool set point shows as it was before hold, humidity set point shows its original value, system is running as inside temperature is above set point. Changing System to AUTO shows both heat and cool set points as they were originally.

So the answer to my question is that setting the thermostat to Dehumidification Away Mode, forces the system to "COOL". Not my preference for what it should do, but as long as I know then I can act accordingly. Note when in the Permanent Hold I could not change temperature or humidity set points, which
correlates to what your customers have said about making remote changes.

Also note that ISU code 0379 was not shown as I went through install set up values, which I might guess means it is excluded if 0380 is set to 1. (Something else I can test).

Now to review my current thermostat settings with the install procedures for the TH8321R1001 menu driven system.
 
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Old 08-26-14, 03:32 PM
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TH8321R1001 installed and operating well.

I found the menu driven system was easy to navigate and enter data.
Looking at the ISU Table documentation you feel like set up will take
a long time, but then the table has all possibilities while the menus are
structured to only show what you can change for the features and function
you have installed or activated.

One preference choice came up for me because of the settings on my
old TH8321U1097 thermostat.

900 Dehumidification Equipment Residential:
<menu values to pick from>
None
A/C with Low Fan
A/C with High Fan
Dehumidifier

The question is if using the A/C for dehumidification which fan choice provides more effective dehumidification? Low Fan or High Fan? My old setting was
High Fan, but I don't know why that was chosen.

Thanks for the help and support.
 
 

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