Reddit reviews Emerson 90 380 Fan Relay 24 Volt Coil, 1

The blinking lasted way longer than an update should take (more than 25 minutes). Reboot fixed it.

I'll take pics at some point soon. For now, here's a back-of-a-napkin sketch from someone else:

http://i.stack.imgur.com/xh39w.jpg

In their case, it's a millivolt system. In mine, it just represents the two wires coming from boiler (Taco zone valve in the mix, too, actually). Short version: the lower left is just the R and W that were coming into my 15-year-old thermostat. It doesn't matter top or bottom which terminal they connect to.

EDIT:

• That's an external transformer, like this one and this one
  
  
• This is the relay (with the NO, 2 and 4, terminals used)

Ok. Actually, it is good that we confirmed HRV activation will turn on the furnace fan.

Disconnect the ACC+ to G bridge at Ecobee.

Based on the tests, we know now that when the thermostat activates fan, the signal of the G wire is not sensed by the HRV and is just passed through to the furnace.

So the only way to use Ecobee to control the HRV is using a dry contact switch between HRV terminals 2 and 6 with terminals 2 and 3 bridged.

The Ecobee ACC+/- connection is a dry contact switch. But that means you will need 2 free wires running from the ecobee to the HRV.

It is possible to use only 1 free wire (which you could free easily using the PEK), by adding a 24vac SPNO relay at the furnace end. This is the cheaper/easier solution if you can’t run new wire easily.

You can buy either a SPNO or SPNO/NC relay. Like this on Emerson 90-380 Relay, Fan, 24 VAC https://www.amazon.com/dp/B000LDCPQS/ref=cm_sw_r_cp_tai_w.qOAb081R1GE

On the relay, connect ecobee ACC+ to coil 1 and coil 2 to furnace Common. Then connect relay NO to HRV #2 and relay COM to HRV #6. Bridge HRV #2 and 3.

ok I'll look around if I can can find one locally.
If not I'll probably just order the one on Amazon.ca it's $19.04 CAD shipped. https://www.amazon.ca/Emerson-90-380-Relay-Fan-VAC/dp/B000LDCPQS

Found a manual for it here. Not clue how to read it, however I'm sure you will ;)
https://www.mouser.com/ds/2/459/Cat_06_pg0115-1627.pdf

I'll let you know once I get one! Thanks again for all the awesome help (and patience!)

Thank you for your reply!

Since its pretty much a gutted shell and nothing OEM remains inside the air handler except the A/C coils perhaps you may be able to help me.

I have this

Endurance Pro Control Transformer 40VA, Primary 120, 208, 240V Secondary 24V, HVAC Furnace Multi Tap, Jard 4031F, Packard 42440 https://www.amazon.com/dp/B07PPK4Y9Z/ref=cm_sw_r_cp_taa_8Y8uDbT9915DS

And this

Emerson 90 380 Fan Relay 24 Volt Coil, 1 https://www.amazon.com/dp/B000LDCPQS/ref=cm_sw_r_cp_taa_h38uDbRWDC8PW

Installed.

Still waiting on this (to go outside) to replace what is there. It's a replacement of what the HVAC fella put on there (and charged me $90 for!). I'm just covering all bases here.

Packard C140A 1 Pole Contactor Coil Contactor, 40 Amp, 24V https://www.amazon.com/dp/B003U81D2I/ref=cm_sw_r_cp_taa_D48uDbAQ9XXN2


Now, I'm confused as to how I would control the fan on/off. I assume some sort of relay, presently the fan bypasses the transformer and relay coil. I don't see a 24v wire on the fan itself and it is working but not turning off. (I have the outside compressor powered off at the box waiting for the coil for that)

Do I need to connect it to another transformer and relay and connect my thermostat to both relays?