HZ432 and TH8320R1002 Setup

HeatingHelpPender

This is a new house and I am not sure the contractor has the thermostats set correctly. Before I bother him, I would like to learn a little how my system operates and if it is correct, move on.

I have a Goodman DSZC16036 2 stage Heat Pump, a Goodman GMVC96060 2 stage gas furnace, a HZ432 zone control with DATS and OAT sensors and 2 zones.

The HZ432 seems correct: It is set up for Dual Fuel: 2 stage compressor and 2 stage dual fuel. The system is set to use the OAT to switch off the heatpump below 25*.

The question is around the TH8320R1003. That is setup as a 2 stage air-air heatpump, with gas/oil backup ( but there is no option for a 2d stage backup in ISU 207? Do I need to specify commercial in ISU 101 to get 2 backup stages?? )

Anyway the main question: there is no outside sensor on the thermostats and the ISU 219 is set to "No Fossil Fuel Kit". This would imply that the thermostat was handling the switch between Fossil fuel and Heat Pump. BUT I thought the HZ432 would do this using it's OAT???

So should ISU 219 be set to "External Fossil Fuel"

What is the problem if it is not set to "Yes" ?

GW

Normally one would use single stage stats when you're using a more.advanced panel like your Honeywell.

Your Honeywell panel does all the thinking, not the thermostats.

njtommy

The t-stats should just be in conventional mode. Let the zone panel control the stages and your duel fuel setup.

John Mills_5

We set the panel up so if 1 zone is calling, 1st stage runs. When the 2nd zone calls, the panel brings on high fire or 2nd stage of the heat pump. Saves on tripping of the discharge air sensor.

HeatingHelpPender

John Mills said:

We set the panel up so if 1 zone is calling, 1st stage runs. When the 2nd zone calls, the panel brings on high fire or 2nd stage of the heat pump. Saves on tripping of the discharge air sensor.

That is kind of how my TH8320 and HZ432 are set up. I am not using the timer function in either the thermostat or the zone panel.

Zone 1 is ~ 70% of the load and that is set for a 2 stage operation.

Zone 2 is much smaller and that is set for single stage. In order to get Zone 2 to work like this, I configured the Zones in the HZ432 for 2 stage but programmed the second floor T/S for single stage operation. This way if Zone 1 gets behind, stage 2 will roll up.

The DATS is set to roll back stages if things get below 40* or above 160*

HeatingHelpPender

njtommy said:

The t-stats should just be in conventional mode. Let the zone panel control the stages and your duel fuel setup.

So what you are saying is to setup the thermostats as 2H,2C with Aux heat? But I don't think Aux heat is an option? or do I ignore the Aux heat function and just let the T/S call for stage 1 or stage 2 heat and then let the Zone controller manage heatpump or gas?

Under "conventional" thermostat configuration, how do I run Emergency heat if needed?

HeatingHelpPender

GW said:

Normally one would use single stage stats when you're using a more.advanced panel like your Honeywell.



Your Honeywell panel does all the thinking, not the thermostats.

I have had trouble in the past using timers to control things especially in humid climates trying to control humidity and temperature. In my case the thermostats have what appears to be good staging built into them and the Zone panel allows the Y1/Y2 E/Aux to be used as inputs, so why not use these capabilities? - Just asking??

GW

I've never pondered that question. But some basics are this-

If you have zones you must use a panel. The panel tells the equipment what to do

However you could get creative and have a primary zone (aka Master) that can run the way you are describing and set your other zones on a more basic zone panel. If you do this then you can't allow the 'other' zones to call on the system.

de-Humidification settings and zoning panels don't really happen together unless there's some system out there i'm not aware of.

HeatingHelpPender

GW said:

I've never pondered that question. But some basics are this-



If you have zones you must use a panel. The panel tells the equipment what to do



However you could get creative and have a primary zone (aka Master) that can run the way you are describing and set your other zones on a more basic zone panel. If you do this then you can't allow the 'other' zones to call on the system.



de-Humidification settings and zoning panels don't really happen together unless there's some system out there i'm not aware of.

Thanks forf the response.

I was not thinking about running in true dehumidification mode using the DS/BK terminals on the HZ432 to the air handler, but rather maximizing run time on low stage by using room temperature and recovery rates to trigger the second stage.

BUT...HOLD THE PHONE... it turns out the GMVC96 furnace does have a "DEHUM" terminal, so possibly I will try connecting the DS/RK to that.

Thanks for making me re-read that section of the HZ432 install manual so I could spot that detail.

From the HZ432 install manual:The DS/BK terminal is used with a variable-speed fan. If the HVAC equipment has DS, BK, ODD, or DHUM terminals, wire that terminal to the DS/BK terminal. When greater than 25% of zones are calling for cooling, this terminal will be energized and the fan will operate at normal speed. When 1 zone or fewer than 25% of zones are calling for cooling, the terminal will be de-energized and the fan will run at a reduced rate, which will reduce the amount of air that needs to be bypassed. This reduces blower speed on most variable speed blowers. Refer to HVAC equipment manufacturer instructions.