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Ecobee3 lite and 2 stage furnace

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  • Feb 12th, 2021 11:32 am
[OP]
Sr. Member
Sep 4, 2006
875 posts
81 upvotes

Ecobee3 lite and 2 stage furnace

Hi,
Got a new 2 stage furnace. Previously had a single stage furnace connected via PEK to the Ecobee. Right now the furnace starts in first stage and then goes to the second stage of heating. Do I leave it like that? The thermostat has the "Fan control in heat mode - Ecobee thermostat".

Do I leave it as it is or any settings/connections to change?

appreciate any help.
Thanks
Happy Koodo customer with S9 and the 25$ unltd Canada plan :-)
23 replies
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Dec 12, 2009
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If you want, you can take the fan control off the of the ecobee thermostat which is what I did. I think the furnace will do a better job than the thermostat on fan run down controls. I also have a multi stage furnace but wired as a single stage (5 wires) so the control board on the furnace looks after the stage controls.
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[OP]
Sr. Member
Sep 4, 2006
875 posts
81 upvotes
thank you will888. So I select - "Fan control in heat mode - HVAC " right? Did you change any other settings to make it more efficient? Just curious.
Happy Koodo customer with S9 and the 25$ unltd Canada plan :-)
Deal Addict
Apr 18, 2005
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Mississauga
I actually had the same question... so will monitor this .. I'm also leaning towards hvac controlling the fan.

Also an installer buddy told me to change the heat threshold differential ... ecobee defaults to 0.2c which means the unit comes on with a slight drop.. depending on thermostat location it may cycle .. I set mine to 1.1c for now.

So far for my house to raise 1c heat means 20min of runtime.. and with new Windows and insulation house holds temp pretty well.
Deal Fanatic
Feb 4, 2015
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I just set heat diff for S1 vs S2 to be like 3F and like 1F diff in temp before furnace turns on... that way S1 always runs first.

Also set S1 to run minimum 25 minutes before S2. Found that on auto the E3 ran S2 more often... house more comfortable on how we have set now.

Tweak the settings and try for few days... tweak more if needed. Everybody differs as to what works for their household.
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Dec 12, 2009
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sandyriver wrote: thank you will888. So I select - "Fan control in heat mode - HVAC " right? Did you change any other settings to make it more efficient? Just curious.
Correct. This means let the furnace control the fan. By the way, this is really not about efficiency in terms of savings but rather optimization. I just think that the furnace controls are better optimized to control itself than a smart thermostat which may use generic settings that are "suitable" for all furnaces. As smart as smart thermostats are, they still do one basic task and that is provide an on/off switch based on temperature measurement.

Your question about efficiency, do you use remote sensors? To me this is the big advantage of the ecobee over my previous thermostat. I can move the temperature measurement around the house to suit comfort needs.
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TLSRULZ wrote: I actually had the same question... so will monitor this .. I'm also leaning towards hvac controlling the fan.

Also an installer buddy told me to change the heat threshold differential ... ecobee defaults to 0.2c which means the unit comes on with a slight drop.. depending on thermostat location it may cycle .. I set mine to 1.1c for now.

So far for my house to raise 1c heat means 20min of runtime.. and with new Windows and insulation house holds temp pretty well.
I just responded in another thread where the problem was furnace short cycling too much. The ecobee differential setting is between 0 to 1.7C with 0.3C increments. A lower value will result in more cycling but a high value can affect comfort. Most of us would be able to sense a 1.7C change in room temperature. The idea is to use a setting where we feel the temperature is pretty much constant while not having the furnace doing too many on/off cycles. I have my settings at 0.3 for both heating and cooling. Creature comfort wins over cycling.
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Deal Addict
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will888 wrote: I just responded in another thread where the problem was furnace short cycling too much. The ecobee differential setting is between 0 to 1.7C with 0.3C increments. A lower value will result in more cycling but a high value can affect comfort. Most of us would be able to sense a 1.7C change in room temperature. The idea is to use a setting where we feel the temperature is pretty much constant while not having the furnace doing too many on/off cycles. I have my settings at 0.3 for both heating and cooling. Creature comfort wins over cycling.
Agreed..i have lowered mine to 0.8. Let's see how that feels for a week.
[OP]
Sr. Member
Sep 4, 2006
875 posts
81 upvotes
will888 wrote: Correct. This means let the furnace control the fan. By the way, this is really not about efficiency in terms of savings but rather optimization. I just think that the furnace controls are better optimized to control itself than a smart thermostat which may use generic settings that are "suitable" for all furnaces. As smart as smart thermostats are, they still do one basic task and that is provide an on/off switch based on temperature measurement.

Your question about efficiency, do you use remote sensors? To me this is the big advantage of the ecobee over my previous thermostat. I can move the temperature measurement around the house to suit comfort needs.
Thanks for clarifying. No, don't use ecobee sensors. I will get them , now that you mention it.
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sandyriver wrote: Thanks for clarifying. No, don't use ecobee sensors. I will get them , now that you mention it.
I really need it because in the summertime, I want the AC to be controlled by upstairs temperature. I cannot sleep if it is hot. In the winter, I want the first floor and to some extent the man cave to be warm. The only way to achieve this is to use additional sensors.
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When you adjust your heat online when away should the flame (heat) change to orange like it does at home.
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Dec 27, 2007
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will888 wrote: If you want, you can take the fan control off the of the ecobee thermostat which is what I did. I think the furnace will do a better job than the thermostat on fan run down controls. I also have a multi stage furnace but wired as a single stage (5 wires) so the control board on the furnace looks after the stage controls.

Does a 2 stage furnace need more wires to work properly?
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Apr 18, 2005
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YES... 6 I think (with AC)
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Dec 27, 2007
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Hmmm, I guess I may not be able to upgrade to a 2 stage then

When I got the ecobee they had to use the power extender kit to add the C wire

Or am I understanding this wrong
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Squirrel99 wrote: Does a 2 stage furnace need more wires to work properly?
It depends on whether you want the furnace to manage the staging or the thermostat. For thermostat control, then you need one extra wire. The minimum wire count for full thermostat control is as follows, one for power, one for fan, one for each stage of heating, one for cooling, one for common. The PEK kit can substitute for the common wire. I have a multi stage furnace but I let the furnace control the staging. In this arrangement, I only need one wire for heat.
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Squirrel99 wrote: Hmmm, I guess I may not be able to upgrade to a 2 stage then

When I got the ecobee they had to use the power extender kit to add the C wire

Or am I understanding this wrong
How many wires in the cable going from thermostat to furnace? If you want the thermostat to control a two stage furnace and you have AC also, then you need a minimum of 5 wires plus PEK for common. If you let the furnace manage the two stage heating, then you need a minimum 4 wires plus PEK for common.
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will888 wrote: How many wires in the cable going from thermostat to furnace? If you want the thermostat to control a two stage furnace and you have AC also, then you need a minimum of 5 wires plus PEK for common. If you let the furnace manage the two stage heating, then you need a minimum 4 wires plus PEK for common.
Ah ok, thanks
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Feb 4, 2015
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Paul61 wrote: When you adjust your heat online when away should the flame (heat) change to orange like it does at home.
Yes, bit of a delay though.
.......
July 13, 2017 to October 25, 2018: BOC raised rates 5 times and MCAP raised its prime rate next day each time.

2020: BOC dropped rates 3 times and MCAP waited and waited to drop its prime rate to include all 3 drops.
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I had a 2 stage furnace several years before purchasing the Ecobee. The furnace would run on the low stage for 5 minutes (IIRC), and if the desired temperature wasn't reached, it would switch to the second stage until the desired temperature was reached.

When first installing the Ecobee, I wired it to manage the 2 stages. The Ecobee also ran the first stage for about 5 minutes before turning on the second stage. So there was no advantage to letting the Ecobee handle the stages, like many of you already have already said,, especially if it meant adding an extra wire.

This year I began to use the "smart recovery" feature of the Ecobee. This feature is designed to have your house already at the desired temperature when you get out of bed at e.g. 7:00 AM rather than just turning on the heat in the morning and perhaps waiting 1-2 hours to reach that temperature.

For example, I have my Ecobee switch to 22' at 7:00 AM and then to 14' at 8:30 PM . With the current outdoor temperatures, my house has only dropped to 15.5' overnight, which means my furnace never ran the entire night, With "smart recovery" enabled, my 1st stage turns on at 4:55 AM, and the temperature begins to rise at a low rate. At 6:30 AM the 2nd stage turns on, and at 7:00 AM I have the desired 22'.

The smart recovery is smart because it knows what the outdoor temperature is, and it knows how long it will take to heat up my home at that outdoor temperature. By bringing up the temperature primarily with the 1st stage, it "should" use less gas, and it brings up the temperature more slowly so that it is a more comfortable change, which I'm less likely to even notice.

I have only been using smart recovery for the last month. Depending on how the next gas bill looks, I hope to continue using it. If your furnace is controlling the stages, smart recovery would still work, but the furnace will not run in 1st stage for more than 5 minutes, and the heat would rise much quicker in the home.

So if you would like to benefit from smart recovery, I recommend letting the Ecobee handle the staging, which will require the extra wire.
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Dec 12, 2009
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Rick007 wrote: I had a 2 stage furnace several years before purchasing the Ecobee. The furnace would run on the low stage for 5 minutes (IIRC), and if the desired temperature wasn't reached, it would switch to the second stage until the desired temperature was reached.

When first installing the Ecobee, I wired it to manage the 2 stages. The Ecobee also ran the first stage for about 5 minutes before turning on the second stage. So there was no advantage to letting the Ecobee handle the stages, like many of you already have already said,, especially if it meant adding an extra wire.

This year I began to use the "smart recovery" feature of the Ecobee. This feature is designed to have your house already at the desired temperature when you get out of bed at e.g. 7:00 AM rather than just turning on the heat in the morning and perhaps waiting 1-2 hours to reach that temperature.

For example, I have my Ecobee switch to 22' at 7:00 AM and then to 14' at 8:30 PM . With the current outdoor temperatures, my house has only dropped to 15.5' overnight, which means my furnace never ran the entire night, With "smart recovery" enabled, my 1st stage turns on at 4:55 AM, and the temperature begins to rise at a low rate. At 6:30 AM the 2nd stage turns on, and at 7:00 AM I have the desired 22'.

The smart recovery is smart because it knows what the outdoor temperature is, and it knows how long it will take to heat up my home at that outdoor temperature. By bringing up the temperature primarily with the 1st stage, it "should" use less gas, and it brings up the temperature more slowly so that it is a more comfortable change, which I'm less likely to even notice.

I have only been using smart recovery for the last month. Depending on how the next gas bill looks, I hope to continue using it. If your furnace is controlling the stages, smart recovery would still work, but the furnace will not run in 1st stage for more than 5 minutes, and the heat would rise much quicker in the home.

So if you would like to benefit from smart recovery, I recommend letting the Ecobee handle the staging, which will require the extra wire.
I am curious whether the ecobee would be able to adapt to how the furnace behaves and adjust accordingly to reach the desired temperature at the desired time even if it is not in control of the two stages.
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