Ecobee premium wiring from old honeywell

lowso · October 6

Good morning all,

I recently purchased ecobee thermostat in order to replace outdated Honeywell .

While attempting to install I noticed I have a red & black wire going to the W terminal and white wire going to the R terminal on the old Honeywell thermostat.

downstairs at the furnace I only see two wires on the control white and black .

any suggestions on how to proceed with install / wiring ?

EdTheHeaterMan · October 6

At the burner, pull back the cloth insulation to reveal the third wire.

The control on your oil burner will not provide you with a C for your thermostat. That control only has R & W that you can connect to. They will be labeled T T so you do not know which one is R and which one is W. when there is only 2 wires, it doesn't matter. but if you need a C then the R and W matter.

EdTheHeaterMan · October 6

If you need a C wire, them you might want to get this

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Carlin-Combustion-98435S-Product-Overview.pdf

or https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Beckett-51950U-User-Guide.pdf

lowso · October 6

I pulled it back third /red wire is not connected to anything

Jamie Hall · October 6

Shame to replace that "outdated" thermostat. It's more reliable — and precise — than anything you can buy today. A lot simpler, too.

I like the Carlin unit that @EdTheHeaterMan suggested, but there's nothing wrong with the other one.

Frankly if it were mine I'd replace the whole burner control with a Carlin 70200 control — a lot more functionality. But that's me. It I were going to do it at all — which I wouldn't, since I wouldn't replace that old thermostat unless I were paid — well — to.

EdTheHeaterMan · October 6

So you found the missing Red wire. We will not need to call Paul Drake on this case. Since it is not connected to anything, what does that tell you?

HeatingN00b · October 6

Would this wiring diagram help (it worked for me)?

lowso · October 6

https://forum.heatinghelp.com/discussion/comment/1813225#Comment_1813225

can the red wire be used as the C wire since it’s not connected to any terminal ?

EdTheHeaterMan · October 6

YES. But why don't you disconnect all the wires at both ends and use the Red wire on the R at the thermostat, use the White wire on the W on the thermostat and use the Blue (or Black hard to tell) for the C on the thermostat. Electricity is colorblind, so make it easy for the next time so the humans don't get confused.

Do you know where to connect the C from thermostat?

EdTheHeaterMan · October 6

https://forum.heatinghelp.com/discussion/comment/1813227#Comment_1813227

YES exactly, but the transformer/relay in that diagram is more expensive then the https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Beckett-51950U-User-Guide.pdf At least the last time I checked it was.

lowso · October 6

https://forum.heatinghelp.com/discussion/comment/1813233#Comment_1813233

no I do not where to connect c from thermostat … it’s all new to me sorry

HeatingN00b · October 6

https://forum.heatinghelp.com/discussion/comment/1813234#Comment_1813234

Oh I sent the wrong image (was driving lol).

I meant to send this picture. This is how I got it working after your suggestion (don't know if it will help the user), but it was simple to follow for me .

EdTheHeaterMan · October 6

You do not have the R8184G primary control, so that will not work.

You have only T T available on the GeniSys control. The F F that is inside the box is not wired up internally the same way as the analogue R8184G. You can not use the transfromer in the GeniSys control to power that thermostat.

The first diagram you sent was correct. and you need a 20 VA or better transformer to power the isolation relay.

You may find the Kool Kit or the A C ready kit less transformer is less expensive, the nyou can purchase a lower cost 24 Volt 20VA transformer to operate it

HVACNUT · October 7

The thermostat wire goes directly from the thermostat to the Genysis control? Then its a steam boiler and likely no other low voltage circuit to use.

Return the Ecobee unless you can have a licensed electrician rewire your boiler with a switching relay like a Taco SR501 or compatible.

Jamie Hall · October 7

Better yet. As I suggested above, "new" is not always "better". Keep that old mercury beauty and relax. Oh yes. It is permissible to turn those old thermostats up or down as wanted by hand…

lowso · October 8

what control board would you guys recommend as a better option / replacement for the Beckett genisys 7505?

Also

Would it be just as simple as swapping control board or would the replacement need to be programmed to work with my boiler ?

Jamie Hall · October 8

I like the Honeywell 70200. It is not all that hard to wire to a different burner — but it isn't plug and play either. You do have to have some idea what you are doing, and why you want to program it, since it gives you a variety of options.

I'd still keep the old thermostat, though, unless you have a good reason other than programmability or a modern look to change.