Honeywell Vision Pro IAQ

[hvac-master]

The IAQ, you don't need to set it up at 2 stage cool to get the affect you are doing with the 802, as long the DHUM is wired to the board as the manual says.

I am utilizing the control in a different method and do not require the IAQ to achieve. This can be achieved with any 2 stage control.

Remove the BK jumper from the control board and wire Y1(Comfort Control) to Y(Furnace) to Y(Outdoor Unit)

Wire Y2(Comfort Control) to BK(Furnace)

Anytime Y1 energizes you will have 80% airflow. If Y1 satisfies the load conditions it will operate 80% for complete cycle. The only time you will have 100% airflow is when the comfort control energizes Y2.

I do not utilize comfort-r (enhanced mode) with this configuration and would not recommend this setup if you are operating at low ambient conditions.

[beenthere]

That method may work.
But you lose the ability the IAQ has to slow the blower during normal operation if the humidity rises while the unit is already running.

For the cost difference between an IAQ and a 8321, you get more for the money with the IAQ. And no special wiring required.

[mayguy]

HVAC.

I did that set up with mine before I got my IAQ, did work out well, but like Been said, if the humidity is high, but the t-stat is running 2nd stage, you not going to get the dehumidity affect.

[hvac-master]

The IAQ thermostat has a single set of normally open dry dehumidification contacts that are designed to operate a whole house dehumidifier .

In fact if you wire the dehumidification terminals directly to BK and the thermostat calls for dehumidification you would run 100% airflow in the cooling mode. You would be required to wire a seperate normally closed relay being controlled by the IAQ that would open on a call for dehumidification and remove the BK circuit to obtain 80% airflow.

In the new ComfortLink/Acculink communicating models the new 900 series comfort control will continue to utilize the 3 degree overshoot method of dehumidification utilized by the 803 series control.

While I realize that the method I utilize may not work for everyone, it has worked in every application I have attempted it in and it has reasonably controlled the humidity by increasing the run cycle and latent capacity of the system.

[mayguy]

In fact if you wire the dehumidification terminals directly to BK and the thermostat calls for dehumidification you would run 100% airflow in the cooling mode. You would be required to wire a seperate normally closed relay being controlled by the IAQ that would open on a call for dehumidification and remove the BK circuit to obtain 80% airflow.

No relay is needed. You wire BK right to the EIM.

In the new ComfortLink/Acculink communicating models the new 900 series comfort control will continue to utilize the 3 degree overshoot method of dehumidification utilized by the 803 series control.

The IAQ is able to overcool if the humidity is 5% over set point.

[beenthere]

DHM1/DHM2, are installer set up as to weather they are normally open or closed contacts.
You set them up for the system you are installing. You can set them to open to slow the blower down. Or to close to slow the blower down.

I think you misread the instructions.

[hvac-master]

I have reviewed the product data and stand corrected. It seems that this can be changed utilizing ISU 379.

The problem is that this is not clearly explained in the installation instructions and is only identified in the product data manual.

[mayguy]

I have reviewed the product data and stand corrected. It seems that this can be changed utilizing ISU 379.

#379 to 1.

Wire from R to DHUM 1 DHUM 2 to BK. No relay is needed.

Then follow the jumper cutting on the notes.

[beenthere]

Once you use the IAQ, you will like the way it can control the blower.

[Cub]

I am utilizing the control in a different method and do not require the IAQ to achieve. This can be achieved with any 2 stage control.

Remove the BK jumper from the control board and wire Y1(Comfort Control) to Y(Furnace) to Y(Outdoor Unit)

Wire Y2(Comfort Control) to BK(Furnace)

Anytime Y1 energizes you will have 80% airflow. If Y1 satisfies the load conditions it will operate 80% for complete cycle. The only time you will have 100% airflow is when the comfort control energizes Y2.

I do not utilize comfort-r (enhanced mode) with this configuration and would not recommend this setup if you are operating at low ambient conditions.

Unknowing homeowner here... Does this mean BK controls fan speed in cooling mode only?

[second opinion]

Unknowing homeowner here... Does this mean BK controls fan speed in cooling mode only?

Cooling and heat pump mode only, no fossil fuel