Need help thermostating a custom secondary heat system

I’ve got a very high output zero clearance fireplace. It has a ducted blower that puts out significant heat. I’ve taken this and branched it to several rooms via several relay activated damper valves. The relays are Zooz z wave. The blower fan is an AC Infinity plugged into a simple smart plug. When the plug is on the blower resumes it’s previous state. I don’t really need to adjust speed on it I run it full.

Here’s what I want to do. Create a virtual thermostat for each room. It would simply activate the the blower fan, open the correct valve based on temp sensors in each room. That is easy with the generic thermostat. The not so easy logic for me is the state dependent “if’s”. What if the blower is already running be cause another room called it. It can run more than one room at a time. The generic thermostat says it needs a toggle action not an on/off state. I also have a heat switch/sensor on the fireplace that triggers an input on the Zooz relay. This will tell the system heat is available from the fireplace at this time. When the fireplace is cold or not in use my main HVAC takes back over.

Also, the blower dumps excess heat into my garage when the house gets too hot from the fireplace so it’s running frequently. If I need to send heat to a room, I close the garage damper to maintain static pressure and retain the heat.

So…call for heat based on temp sensors, ensure the blower is activated regardless of its current state, pivot my damper valves accordingly based on its current state(s), and deactivate to off or the secondary state if like in my example above it was bleeding off to the garage. I hope this makes sense. Any help, guidance, or suggestions are very appreciated. Thanks

If each room is a generic thermostat and each room has a switch then I would put them all in a group and have the blower trigger on the group.
(I think that is correct)

Or just make a template sensor with or on all room switches.
That should be correct, any room needs heat and its switch turns on, the template or group also turns on.

Thanks, I’ll message around with that.

Not quite finding a way yet. I have not only a more complex algorithm than the Generic Thermostat but also preconditions that have to be checked against.

“Is fireplace in use” NO: thermostat disabled
“Is fireplace in use” YES: Thermostat enabled
“Fall below temp” YES: Open zone valve, switch on (not toggle) blower fan
“Other Zone Already Heating?” NO: Proceed as above
“Other Zone already Heating?” YES: Open zone valve, blower is already running (so no action)
“Temp Reached” YES: Close zone valve, turn blower off
“Temp Reached” YES: Close zone valve, Other Zone Still Heating? YES: Do nothing with blower fan(leave on for the other thermostat action)

As you can see running it simple could disrupt simultaneous calls for heat. When one thermostat action is running the other no longer to need to toggle/turn on the blower. Only when none are running should the blower be off. Also, they all need to check weather the fireplace is running because if not, it defaults to my primary heating system, since there is no heat from the fireplace. In which case, it would just disable the virtual thermostats.

"Is fireplace in use” NO: thermostat disabled - use an automation to turn on/off the thermostats
“Is fireplace in use” YES: Thermostat enabled - same as above.
“Fall below temp” YES: Open zone valve, switch on (not toggle) blower fan - standard feature of generic thermostat. It turns on/off a switch. Use this.
“Other Zone Already Heating?” NO: Proceed as above - again standard feature of generic thermostat 
“Other Zone already Heating?” YES: Open zone valve, blower is already running (so no action) - if you group the switches and use this as a the trigger for an automation then it will not trigger since the group is already on.
“Temp Reached” YES: Close zone valve, turn blower off - that is what a thermostat does.
“Temp Reached” YES: Close zone valve, Other Zone Still Heating? YES: Do nothing with blower fan(leave on for the other thermostat action) - again grouping will make sure it does not turn off the fan unless all thermostats are off.

I believe you think it’s more complex than it actually is.
Just group the thermostat switches and use this as your trigger to turn on/off the fan.
Use an automation to turn on/off the generic thermostats when the fireplace turns on/off.

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It’s totally possible I am overthinking it. New systems and my brain don’t get a long well but once I see and use all of the nodes it becomes second nature. Appreciate the advice/feedback

Edit: Makes total sense now, got it going. Letting the group of damper switches engage the blower fan via automation states.

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