Installing 4 Ecobee4 thermostats in my house


Old 11-12-17, 08:35 PM
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Join Date: Jun 2017
Location: United States
Posts: 6
Installing 4 Ecobee4 thermostats in my house

Hi guys,

I just purchased my first house and I have 4 thermostats in the house that I want to replace with the Ecobee4. I am not an expert in HVACs, air conditioning systems, boilers, etc. I am a novice and I am learning as I go along. So please be gentle when replying to this post so I can understand your answers. I appreciate your patience!

I have an Energy Kinetics System 2000 boiler. I don't 100% understand how my A/C system is set up, but I think I have two A/C handlers in the attic and I definitely have two A/C condensers outside. The A/C has two zones in the house whereas the heating system has three zones.

Here are the thermostats:

1) Family Room: Controls A/C and heat. This thermostat has the RH, RC, Y, W, G wires.

2) Dining Room: Controls heat on the main level. This thermostat has the R and W wires.

3) Master Bedroom: Controls the heat on the upstairs level of the house, where the bedrooms are. This thermostat has the R and W wires.

4) Hallway: This thermostat controls the A/C for the main level and upstairs level of the house. This thermostat has the RC, G, Y wires.

I do not have a C wire or extra wires to convert into a C wire for any of these thermostats. I spoke to both Ecobee support and a technician from Energy Kinetics (who makes the System 2000 boiler).

Energy Kinetics sent me this PDF:

They also said: The Ecobee t’stat is compatible with our System Manager as a Heat only thermostat it cannot be used for Heat and A/C without an isolation relay. The connections for heat only are A2 to C, A1 to R and W to T1,T2,T3…. See diagram I attached labeled Nest thermostat. The Ecobee requires power all the time so you will need a three conductor cable running to the stat or you can use the Common Maker from Fast Stat if you only have a 2 conductor cable.

Family Room
If you are going to use the Ecobee thermostat it will require an isolation relay see diagram for installation
Dining room
No issues if using the Ecobee you will need three conductors connected to the Manager A2 to C, A1 to R, Tx to W (Tx is whichever zone t1,t2,t3…)
Master Bed room
Same as Dining room
Hallway has no heating connections

Ecobee support told me this: As per the explanation , if you have 2 different systems , that is boiler and a AC ,controlled by 1 thermostat , it becomes a Dual transformer set up . In this set up , ecobee will have the following set up :
R wire from AC >> RC
Y wire from AC >> Y1
G wire from AC >> G
C or spare wire from AC >>C
R wire from Boiler >> RH
W wire from boiler >> W1

Please note that C wire should always come from the AC/compressor unit .

So, I am a little confused since it's getting a little technical for me and I am new in trying to figure this out.

1) Can anyone more knowledgeable than me try to dumb this down and explain it in more simpler terms?

2) It sounds like no matter what, I need to hire an electrician to install C wires if I want all 4 ecobee thermostats to work?

3) If I need to have C wires installed, how much would something like that run? The ceiling in the basement where the boiler is located is exposed. Is it possible to run a C wire down the wall from each thermostat without breaking into the wall?

I know this is a long post, but I appreciate any help you guys can provide. Thank you so much!
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Old 11-12-17, 10:08 PM
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Join Date: Oct 2012
Location: Northern NJ - USA
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Welcome to the forums.

An awful lot of wifi stats in one house. Here is a basic way to handle it.

Family room - (RH, RC, Y, W, G) - ok with two wires Rh & W for the heat. This may or may not need a relay. Will need to check further. If relay needed.... it will be easy to wire. Convert the G wire to a C wire. That means you will lose FAN ON control for that stat.

Dining room - two wires for heat - Since this on the first floor it should be semi easy to run a third wire for C or just run a 3+ wire cable and abandon the two wire.

Master bedroom - two wires for heat. Much harder to get a cable to. The Fast Stat common maker could work here. It uses two wires. It converts those wires to R and C. The W (heat) command is encoded and sent on the R wire. This setup could be used in the Dining Room too.

Hallway - (RC, G, Y) - Convert the G wire to a C wire. That means you will lose FAN ON control for that stat.

Always better to run the C wire but not always easy. If you couldn't live without the FAN ON in the two A/C locations you could use Fast Stat 1000's to give you the control back with a C connection. Technically the PKE's should work but they seem to be more problematic and I won't use them.

Some food for thought. Not hard to do but the wiring is somewhat complicated.
Old 11-13-17, 06:38 PM
Thread Starter
Join Date: Jun 2017
Location: United States
Posts: 6
Hey, thanks for the reply.

I would prefer not to convert the G wire into a C wire. I don't want to lose fan control.

Where does the fast stat common maker go? Does it go behind the wall or is it installed where the boiler is?

It sounds like the best solution (if possible) is to run C wires from all the thermostats except the family room thermostat, which would use the isolation relay?

How much does it normally cost to have a C wire put in? I just bought this house and plan on being here a very long time, so I'd rather do it right than a quick measure fix.

Thanks again!
Old 11-13-17, 08:22 PM
PJmax's Avatar
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Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 46,946
Ultimately... running the correct thermostat wiring with a few spares is the best way to go.

How much to do it.... I couldn't begin to guess. It depends on how the house is set up. If there is a direct chase way to the attic..... like a main drain stack or chimney.... the cost will be lower. It's all about fishing the wires in the wall. Every house is different.

The Fast stats have two parts. One is small and goes in the wall behind the stat and the control module goes at the equipment end.

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