Author Topic: ecobee 3 and HRV/furnace  (Read 1175 times)

Offline Pauly

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ecobee 3 and HRV/furnace
« on: February 09, 2019, 05:01:46 PM »
Hello guys.
newbie here.

I would like my furnace fan to come on when I activate my hrv.
Do I need a furnace interlock relay?
I have a venmar 43110, furnace, AC, Ecobee 3 lite.
I have included pictures.

Cheers.

Offline Admin

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Re: ecobee 3 and HRV/furnace
« Reply #1 on: February 09, 2019, 05:18:07 PM »
The Ecobee 3 Lite won’t control an HRV so I assume you’re still using the HRV control.

The relay part number is listed on your 3rd picture.  You need to order Part #12658 and connect low voltage wiring to the furnace.

The Ecobee 3 or 4 would control the HRV and synchronize the furnace fan without that relay.

Offline Pauly

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Re: ecobee 3 and HRV/furnace
« Reply #2 on: February 09, 2019, 05:49:22 PM »
I looked high and low and can't seem to find that said relay.
Any ideas?

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Re: ecobee 3 and HRV/furnace
« Reply #3 on: February 09, 2019, 06:05:09 PM »
It looks like it's been discontinued.  You might find 3rd party sellers like this one,

https://www.pinterest.ca/pin/102456960247474462/?lp=true

You could buy any SPDT relay with 120V coil and connect the coil to the wires leaving the #5 and #7 pins on the molex connector.  Then follow the 3 wire interlock diagram in your picture to connect the relay to the furnace and thermostat.

Offline Pauly

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Re: ecobee 3 and HRV/furnace
« Reply #4 on: February 09, 2019, 06:17:30 PM »
Thanks.
any other sites that sell it?

Could you provide a diagram or picture of the wiring you mentioned? I'm a green newbie.

Offline Admin

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Re: ecobee 3 and HRV/furnace
« Reply #5 on: February 09, 2019, 07:05:34 PM »
You could buy this White Rodgers #90-294Q relay,

https://www.amazon.ca/Emerson-90-294Q-SPDT-Enclosed-Relay/dp/B000PY28KG

And use this 18/3 24V wire,

https://www.homedepot.ca/en/home/p.faslvt-copper-thermostat-electrical-cable---183-brown-15m.1000663294.html

Install the relay inside the HRV and run wiring from the HRV into the furnace and follow the attached diagram.  You'll need to crimp on 1/4" female spade connectors to connect your wiring to the relay,

https://www.homedepot.ca/en/home/p.terminal-kit-175-pc.1001012519.html

https://www.homedepot.ca/en/home/p.multi-purpose-6-in-1-tool.1000421422.html

I'm not sure if pins #5 and #7 on the HRV 9-Pin Molex plug already have capped wires attached.  If not you would have to crimp on a certain type of Molex crimp terminal onto the ends of the wires coming from relay terminals #1 and #3.  The next link is to a wiring assembly you might be able to use.  You can cut the molex connector off and only use 2 of the 3 wires.  I'm not sure if this is the right size for your HRV 9-Pin Molex plug though.

https://www.pololu.com/product/1798



Offline Pauly

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Re: ecobee 3 and HRV/furnace
« Reply #6 on: February 10, 2019, 08:50:09 AM »
Thanks again. ;D

Is there any does and don'ts I should be aware of ?

Cheers

Offline Admin

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Re: ecobee 3 and HRV/furnace
« Reply #7 on: February 10, 2019, 09:05:43 AM »
Just unplug the HRV and turn off the furnace power switch.  It's all low voltage so not much can go wrong.

Offline Pauly

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Re: ecobee 3 and HRV/furnace
« Reply #8 on: February 12, 2019, 05:13:56 PM »
Thanks again.

I have a few questions about the operation. Bear with me, I like to know how machines work in my home.

When I press the hrv button in the bathroom, does it activate the furnace fan right away or is there a delay? Does it run on low or high?

Does the hrv turn on when the furnace heat/ac is on ?

Is there a way of balancing the unit without calling an hvac pro and/or a gauge ?



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Re: ecobee 3 and HRV/furnace
« Reply #9 on: February 13, 2019, 07:14:03 PM »
Quote
I have a few questions about the operation. Bear with me, I like to know how machines work in my home.

When I press the hrv button in the bathroom, does it activate the furnace fan right away or is there a delay? Does it run on low or high?

Does the hrv turn on when the furnace heat/ac is on ?

Is there a way of balancing the unit without calling an hvac pro and/or a gauge ?

I missed this post.  I think unless you have a control with both MIN and MAX the high speed fan will always run.  The HRV should run anytime the main control or bathroom timers are turned on, regardless if the furnace or AC are running or not.

Without a digital manometer or magnehelic gauge you won't be able to balance the HRV.