Two Wire R8285A Fan Control with Ecobee Thermostat?

Corvette1974

Hello,

I'm trying to setup my old boiler with an Ecobee 3 lite thermostat. Originally had just the T-T thermostat wiring, but I did run an additional wire to be used for C. I have an R8285A fan control relay and a R8222B relay….can this setup be made to work with an Ecobee thermostat? From what I gather I should be able to do C-C, R-R and W-G(?) but then not sure how to actually wire the boiler control TT wires with the rest of the setup.

As a side note, although my heat still works fine, the C-G wires on the relay have zero or very little (maybe 6V AC), I'd think it needs the full 24V AC there so I may need a new transformer/relay anyway

EBEBRATT-Ed

You shouldn't have to change the T & T connections on the boiler. Which control was the old two wire thermostat wired to??

Need more info and pictures to help you out

Corvette1974

Corvette1974

The T-T connection originally went directly to the thermostat. The smart thermostat needs to be wired into the controls itself for the constant power and I'd assume that involves branching off the fan controller.

My Thermostat Wires Connect to T/T at my Heating Equipment, How do I Install an ecobee?

Here is what they say

EdTheHeaterMan

I am not sure what boiler you have that is using that transformer and relay, but this is a pretty generic example of what you might have. You are correct with your "to do C-C, R-R and W-G(?) but then not sure how to actually wire the boiler control TT wires with the rest of the setup"

The black wires that have the T T tags on them are the R and the G from the transformer. You can use them with wire nuts or you can eliminate them and connect the R from the Thermostat directly to the R on the transformer. and the G on the transformer to the W on the thermostat. That will allow you to use the C on the transformer to connect to the C on the thermostat.

Hope this helps you

Corvette1974

Thanks for the info. My system is a forced air oil burner (no AC) and it has the two speed fan where it builds the draft while running the boiler then it goes to full throttle after about 30 seconds then it cools down after shutting off the oil burner.

If the original thermostat ran directly to the boiler control T-T wire, and I remove those wires as the new thermostat requires actual power not just a switched connection, what then connects to/controls the T-T posts on the boiler control?

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1824241#Comment_1824241

This is quite confusing because you may be using the term boiler incorrectly. A boiler is a machine that heats water. a water heater can loosely be called a boiler. Boilers for space heating are often connected to radiators that are filled with water or steam that heat the individual rooms. There are no ducts connected to a boiler and no fans involved.

A furnace on the other hand heats air and is connected to ductwork. All the modern residential furnaces have a fan that forces the cold air from the home over the heat exchanger of the furnace to blow warm air through the ductwork.

If you have a furnace with a fan. then you have a different wiring diagram and your thermostat may be connected differently. Can you tell us the make and model number of your heater. Or post a photograph of the heater. Then we can help you better. And perhaps another photo of the wiring compartment where T T is located

Corvette1974

Correct, I apologize for the miscommunication. It is a forced air furnace. About a 1986 model with a traditional Oil gun burner/Sid Harvey controller. I'll get specifics tonight when I'm back home.

HVACNUT

Why did you pull the relay? On the Fan Center there should be R C G W Y. Connect the Common to C. Just make sure R on the Fan Center is R on the thermostat. And W is W.

EdTheHeaterMan

@HVACNUT, This oil burner may have a different T T connection than W and R on the fan center.

Perhaps the T T from the R8184G needs to be connected some how. Until I see the wiring diagram, it is hard to say where to get the C wire for the thermostat from. A 1986 oil fired furnace with a fan center included… that may have several different wiring configurations…. Not enough Info yet.

Corvette1974

Please see these images. Although you'll see a green wire as part of the new C Wire I ran, this is exactly how it was wired before, with the red/white wire going from the T-T to the thermostat. Nothing was ever connected to the terminals on the transformer apart from the factory black/blue wires. I dont see any way to logically connect the thermostat then wire something to something to get the T-T control running again.

HVACNUT

Oof. @EdTheHeaterMan , you're right. The thermostat is going directly to TT on the primary instead of the fan center.

W on the Fan Center SHOULD energize the coil on an isolation relay to close TT on the burner.

No Ecobee the way it is. "Water water everywhere, and not a drop to drink."

Corvette1974

Right - I'd think there would be a way to setup the Ecobee to the transformer (which I think is dead/not even sure if that is possible while still having the boiler operate?).

Then peel off the relay to trigger the T-T. I'm pretty good with wiring and electrical but this one is just a mental block for me…

EdTheHeaterMan

Right - I'd think there would be a way to setup the Ecobee to the transformer (which I think is dead/not even sure if that is possible while still having the boiler operate?).

please read this :

https://forum.heatinghelp.com/discussion/comment/1824249#Comment_1824249

You have a furnace. You do not have a boiler.

EdTheHeaterMan

I believe that your cooling relay is not being used

Here is a wiring diagram from your manufacturer that is for a newer model. If you can photograph the one that is on the inside of the blower compartment That will help.

I have modified this diagram to what I believe you have. It may not be correct but this is the best I could do with the information provided.

The R8184G primary control has a small transformer inside that may be powerful enough to operate the thermostat. The R side of the trnsformer is connected to the T that is closest to the edge. The W should get connected to the other T and the C xhould be connected to the bottop F closest to the edge. That should work for you

This is what is inside the R8184G

Hope this helps.

Corvette1974

"Boiler" old habits die hard…. My brain associates an oil gun with a "boiler"

That worked perfectly!! Ecobee is online and operational. Thank you for all your help….add it to the list of things that work. Ecobee right to the furnace control relay!