Any HVAC folks? Whole House Humidifier Install Question

[mastergun]

EDIT: Sorry for the title, I am installing a DEhumidifier not a humidifier. I was dealing with a kid while writing this post and also screwed up the return/supply. I’ve fixed everything in this edit.

This is a follow-up from a previous post. I plan on installing an Aprilaire E080 Dehumidifier and have a few questions. I just have a few questions and hope to get some answers and recommendations. Thanks in advanced for any advice.

The installation instructions for the dehumidifier are not very clear.

My HVAC system is in an unconditioned attic. I have a 2 story house with a zoned system to each floor. The zones are controlled by dampers and a Honeywell HZ221 Truzone. My preference is to not install a separate return air grill and I want to tie into the existing return and want to control the humidity level with my Ecobee Smart Thermostat.
Do I need to tie the dehumidifier into both zones? If not, is one floor preferred over the other?

I don’t have enough space on the return plenum, so my only option is to install the dehumidifier pulling return from one zone, unless I use a Wye on one of the return ducts into the return plenum. However, I am able to install the dehumidifier supply into the supply plenum where both zones are fed.

Will the above configuration work? This is a Return to Supply setup and does not require the HVAC fan to run when the humidifier is running. I could do a Return to Return install but would only pull return from one floor (1st or 2nd floor). Is there a preference in this case? I’ve heard the house will equalize out, but is this actually as effective?

My next question is related to wiring.

The first image is the instruction manual wiring directions. The second picture is my current wiring in the HVAC compartment. The bundle of wires with the wire caps lead to the Zone control board. Based on the install instructions I connect the dehumidifier wiring into the HVAC equipment. Do I just add it into the appropriate wire with the existing wiring cap? There isn’t a wiring block.

Again, thanks in advance for any answers and advice!

Robert

Install Instructions


My Current Wiring


Install Configurations

[Fishndan]

Or just put a pan of water in front of a few of your heat ducts when you need humidity (out of the way location like under a bed, etc. if you/your wife doesn't like how it looks.). Save a bunch of money, and you won't get flooded by a POS Aprilaire whole house humidifier or have it dump humidity into your basement and cause mold - voice of experience....

[Rick H]

Had one for 30 + year never an issue. Can't help with the install had my HVAC guy do it with the new furnace.

[mastergun]

Or just put a pan of water in front of a few of your heat ducts when you need humidity (out of the way location like under a bed, etc. if you/your wife doesn't like how it looks.). Save a bunch of money, and you won't get flooded by a POS Aprilaire whole house humidifier or have it dump humidity into your basement and cause mold - voice of experience....

I’m installing a DEhumidifier not a humidifier. I’m in southwest Georgia, I don’t need any extra humidity.

[Racingfan]

Im an HVAC Journeyman. I will always prefer to install a dehumidifier in a return to supply bypass... Meaning ducting the dehumidifier from the return to the supply... If you can NOT do that, I would install a return to return. You want the unit to have the abilitiy to dehumidify the entire home whenever possible via all ductwork... You said there is no room on the supply plenum without installing a wye. Thats a tough deal... By installing the unit in the return it will have the ability to run dry air into whichever, (or both) zones whenever they call.
Does this help?

[Racingfan]

Btw, the diagram you shared, shows the exact wiring setup needed... The dehumidifier will run the hvac unit fan when it calls for dehumidification without an air conditioning call...
If you have a zoned system, whenever a thermostat calls for cooling it will open the damper to its own zone via the zone control and run as needed... If the thermostat calls for dehumidification (without cooling), the thermostat will send a signal to the zone control to run the fan. This will have to be addressed when wiring is done. Your ecobee thermostat has the ability to call for dehumidification?

[Racingfan]

I can tell by your wiring of the air handler that you have a Bryant unit. Is it variable speed by chance? I can tell by the model number if you dont know.

[Transom]

You live in Georgia and want to add humidity to your house

[Fishndan]

I’m installing a DEhumidifier not a humidifier. I’m in southwest Georgia, I don’t need any extra humidity.

Then why does the subject line say "Humidifier"?

[Rick H]

I’m installing a DEhumidifier not a humidifier. I’m in southwest Georgia, I don’t need any extra humidity.

I was wondering but I wasn't going to assume I read humidifier in the title.

Now on the other side of that isn't that pretty much what a/c is? At least that's pretty much how I use mine. Just asking!

[mastergun]

You live in Georgia and want to add humidity to your house

Shit! You're right, mistake on my part. I was wondering why the questions on adding humidity. :)

[BroWhoop]

An a/c does dehumidify, however you have to enough runtime to achieve a desired setpoint. In a high temp / high humidity region a standard a/c will be sized for to handle the high temp. This will works fine until the heat subsides, then the unit will no longer dehumidify enough. 2 speed units or inverter(variable spd) units most times will take care of dehumidification. Dehumidifiers work well in the right application. Retired a/c (mechanical) 47 years, body still aches.

[mastergun]

Im an HVAC Journeyman. I will always prefer to install a dehumidifier in a return to supply bypass... Meaning ducting the dehumidifier from the return to the supply... If you can NOT do that, I would install a return to return. You want the unit to have the abilitiy to dehumidify the entire home whenever possible via all ductwork... You said there is no room on the supply plenum without installing a wye. Thats a tough deal... By installing the unit in the return it will have the ability to run dry air into whichever, (or both) zones whenever they call.
Does this help?

It does thanks. I screwed up my initial post due to some distractions while writing the post. I do have access to the supply plenum so will be able to send conditioned air to both floors. But I don’t have access to the return plenum so will only be able to pull unconditioned air from either the 1st or 2nd floor. Is there any preference from which floor to pull from?

Btw, the diagram you shared, shows the exact wiring setup needed... The dehumidifier will run the hvac unit fan when it calls for dehumidification without an air conditioning call...
If you have a zoned system, whenever a thermostat calls for cooling it will open the damper to its own zone via the zone control and run as needed... If the thermostat calls for dehumidification (without cooling), the thermostat will send a signal to the zone control to run the fan. This will have to be addressed when wiring is done. Your ecobee thermostat has the ability to call for dehumidification?

So do I just connect the dehumidifier wiring into the wire nuts in that bundle? The wires from that bundle go from there into the Zone controller.

Yes, my Ecobee can call for dehumidification.

I can tell by your wiring of the air handler that you have a Bryant unit. Is it variable speed by chance? I can tell by the model number if you dont know.

I’m not sure if it’s variable speed.

Thanks for taking the time to answer the questions!

[Rick H]

An a/c does dehumidify, however you have to enough runtime to achieve a desired setpoint. In a high temp / high humidity region a standard a/c will be sized for to handle the high temp. This will works fine until the heat subsides, then the unit will no longer dehumidify enough. 2 speed units or inverter(variable spd) units most times will take care of dehumidification. Dehumidifiers work well in the right application. Retired a/c (mechanical) 47 years, body still aches.

Great answer thanks and now I understand and get it. We have high humidity here but most of the times its with heat. I still rise the a/c temp the hotter is gets then have to lower it into the fall just to keep the system cycling. but on average only a 4 degree swing most of the time just a bump just depends.

[mastergun]

An a/c does dehumidify, however you have to enough runtime to achieve a desired setpoint. In a high temp / high humidity region a standard a/c will be sized for to handle the high temp. This will works fine until the heat subsides, then the unit will no longer dehumidify enough. 2 speed units or inverter(variable spd) units most times will take care of dehumidification. Dehumidifiers work well in the right application. Retired a/c (mechanical) 47 years, body still aches.

In southwest GA, the AC just isn’t enough without keeping the house really cold, or at least colder than I prefer. My wife also has asthma and dehumidifying the entire house will help with that.

[mastergun]

Then why does the subject line say "Humidifier"?

Because I’m an idiot.

[BroWhoop]

In southwest GA, the AC just isn’t enough without keeping the house really cold, or at least colder than I prefer. My wife also has asthma and dehumidifying the entire house will help with that.

Running too cold isn't good. Dehumidifier is probably your best option without replacing equipment. Make sure you don't have any extensive infiltration of outdoor air, anything that could allow excess humidity. If all is good a correctly sized dehumidifier should take care of your issues.

[Racingfan]

You will need to install the dehumidifier wiring on the zone panel not the air handler. The diagram you have shows exactly how to wire it...
As far as ducting goes, and not having access to the return air plenum, is it possible to run a duct to both the up and downstairs? If so, that is what I would always recommend.
If not, its not a huge deal... Moisture will go to dry air by the laws of physics. So I wouldn't worry too much about it. But if possible, as I said before, I would always try to run the dehumidifier into the supply from the return... Essentially the entire home is the return.

[Racingfan]

Your ecobee thermostats will both wire into the zone control panel on their own thermostat INPUT terminals.
The zone control OUTPUT terminals go to the air handler. I would wire the dehumidifier to the OUTPUT terminals of the zone board for simplicity... It will be more accessible and make for easy wiring. You will need to obviously shut off the power to the air handler before doing this... There is a low voltage fuse that will most likely (BUT NOT ALWAYS) save you if you wire it wrong... It is always best to hire a professional to do these things... But I understand if you want to do it yourself.
R - 24vac Hot
C - 24vac Common
G - Fan input
Y - Cooling Call
W - Heating Call
You'll notice in the diagram that the wire going from the "thermostat or zone board" is disconnected and ran straight to the dehumidifier controller. Then the from the dehumidifier controller back to the unit "G" terminal.
This is so the dehumidifier controller can independantly call for the HVAC unit fan when it calls only for dehumidification. It has to be wired correctly or the heating and cooling fan operation will not function properly

[Racingfan]

Im also wondering how the Ecobee calls for independant dehumidification? Does it have a special terminal for this? This is why I was asking if you have Variable speed.
You do not have variable speed btw. I can tell by the picture.