ecobee for 7-zone hydronic heating +forced air?

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  #1  
Old 06-24-19, 05:15 PM
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ecobee for 7-zone hydronic heating +forced air?

Hi & TIA for any help.

We have (to me) a complex HVAC situation. It’s a 3 story (2+finished basement) mostly-summer house in the northern mid-west US (so, quite cold in winter). We’re often not there during the winter. Goals are:
  • Ensure it doesn’t freeze during the winter while we’re gone
  • Simplify control of the overall system & enable monitoring
  • Reduce cost. We spend a pretty huge amount on utilities, and I expect it’s because it’s inefficiently setup.
The house has:
  1. 3 older carrier furnaces, 1 per floor. 2 w/ AC (no AC in basement).
  2. Separate ducted dehumidifier for the basement
  3. Newer Bryant Evolution system w/ 3 baffles (forced-air heat + AC for the newer parts of the basement and main floor, put in by the prev owner who did the remomdel)
  4. 7-zone hydronic in-floor heating system under the floor of most of the basement & main floor…again, put in by prev owner. each zone has an in-slab temp sensor. there's a sep boiler for the hydronic system from the regular water heater.

In total, we have like 13 thermostats.

3 on the carriers
1 control specifically for the dehumidifier
2 for the Bryant (one per floor)
7 for the hydronic in-floor heating.

I gather ecobee can't handle Bryant’s proprietary thermostat interface or the baffles, so we’ll have to leave those alone. correct?

Each of the 7 hydronic thermostats controls a zone. The existing ones (Tekmar 508s) have both an air-temp sensor and a wired in-slab sensor going to them.

Questions:

- can Ecobees (either residential or commercial) handle the hydronic heating? It'll do the right thing wrt the long cycles that type of system takes? Is there a way to connect to the slab sensors? The Tekmar manuals, at least, make a big deal out of those.

- if not ecobee....anyone got a better suggestion?
- what about the dehumidifier? it's a separate system w/ a separate control currently. Any way to integrate it w/ another thermostat...or will I need _another_ ecobee for that? Can the eb even handle it? got a better idea?

I don't need tons of fancy home automation - just easy way to return everything to the 'away for the winter' or 'here for the summer' modes and the ability to see remotely what's going on. We're spending a super high amount on utilities for this house and I expect the issue is it's not practical to get all 13 controls set in a collectively efficient manner. so visibility into what's running, when, and why would really help.
 
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Old 06-24-19, 05:45 PM
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You're right. It's fairly complicated.
As far as I know.... the Ecobees can't use the Tekmar slab or air temp sensors.
When you talk about the Bryant system...... baffles = zones ?

I don't see an easy way to control your home remotely.
 
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Old 06-24-19, 05:58 PM
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How important are those slab sensors, really? If we just ignore them and replace the tekmars with ecobees, using only their ambient air sensors, what happens? Will they even handle the hydronic correctly?

re: the Bryant. Thereís 2 zones, but 3 sects coming off the unit and they each have a butterfly valve in them that the Bryant is controlling. So, as I understand it, the unit can flow differential amounts of air to the upstairs vs downstairs.
 
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Old 06-24-19, 06:10 PM
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As far as I know.... the Ecobees aren't designed to use any remote sensors.

One of the Redlink series of the Honeywell line may be able to use those sensors.
My forum partner would know that better.
 
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Old 06-24-19, 08:29 PM
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Accessories

It looks like that slab sensor is just a 10K thermister.

I have installed Eobees with remote wireless sensors but not wired.

Honeywell quickly comes to mind but I can check on that Ecobee.

Today I worked on a home with 11 Honeywell Prestige IAQ thermostats.

That Evolution zone control is a great option with an outdoor unit with an inverter compressor.

The Carrier Infinity 19SEER inverter can ramp the compressor up or down depending on the number of zones with a demand. It kinda runs like a 5 stage compressor so it is great with motorized zoned systems. The Bryant Evolution has an equivalent model.

A WiFi user interface is available for the Evolution zone control .
 
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Old 06-24-19, 08:42 PM
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https://images.homedepot-static.com/...23e7505643.pdf

I don't see wired sensor terminals on the Ecobee 4.
 
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Old 06-24-19, 08:45 PM
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It looks like the Honeywell Lyric T5 has wired sensor terminals...



https://www.doityourself.com/forum/t...tallation.html
 
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Old 06-24-19, 09:52 PM
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Looks like the ems si supports it. Any drawbacks to going with that? Not so thrilled about spending 250x7 for thermostats but see few other options.

 
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Old 06-24-19, 10:20 PM
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But, Iím still unclear on the most basic questions:

- is a slab sensor actually needed? Is room air temp good enough?
- can the ecobee effectively control a hydronic system? I know itís possible, but is it using the system correctly? Nest lists them specifically, as though it controls hydronic differently than forced air. Is that marketing only? Can the ecobee or Honeywell(say) do just as well?
 
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Old 06-25-19, 06:07 AM
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Seems like the cycles per hour will be lower when configured for hydronic heating.

Is the slab heat the only source of heat in the zones that have it? I would expect the heat to run much longer to satisfy a sensor that isn't in the slab.
 
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Old 06-25-19, 07:47 AM
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" Seems like the cycles per hour will be lower when configured for hydronic heating."

is there such a setting? I haven't seen one. or, do you mean that it'll just do it automatically because the higher thermal capacity of the slab will force longer heat/cool-off cycles?


"Is the slab heat the only source of heat in the zones that have it? I would expect the heat to run much longer to satisfy a sensor that isn't in the slab."

that makes sense. Each of the zones w/ hydronic heating also has (one of the 4) forced air furnaces heating it.
 
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