Connecting Nest thermostat to Genisys 7505 oil burner
Hello!
I currently have an oil furnace that uses a GeniSys 7505 120v burn control that is connected to a Honeywell round basic thermostat with 2 wires (Red and White). I wanted to upgrade to a Nest Thermostat E, so, I turned off the furnace and swapped out the thermostats. When I powered the furnace back up, the Nest began booting, but, I could hear the furnace "pulsing". After doing some research, I came to the conclusion that I need to add a C wire to provide more power. After looking a bit more into the furnace, I see there is a White Rodgers 90-113 fan controller in it, which has a C wire on it. Can I just run a wire from that C terminal on the fan controller to my thermostat and get power for the Nest? Or is there more involved?
GeniSys 7505 top view
GeniSys 7505 side view: Tw and Tr wires go to the Honeywell Thermostat
Honeywell Thermostat: red wire is connect to R + Rc and the white wire is connected to W
White Rodgers 90-113 fan controller
White Rodgers Wiring
I noticed while posting this, the white and red wires are in my mind "swapped" on the furnace: the White wire is connected to Tr post, while the Red wire is connected to the Tw post. This is the way the wires have been for a long time: does it not matter which is connected to which, I take it?
Thanks for your help!!
Bruce
Last edited by PJmax; 12-16-19 at 05:13 PM.
Reason: resized pictures
In my opinion..... a nest E is not directly compatible with your TT system.
You need a thermostat with an Rh and Rc like the regular nest.
That fan center has nothing to do with the burner control. That C on it is not a C for the two TT terminals.
You could use a full size nest and four wires or a 24vAC power supply at the nest itself.
Actually if you have three wires from the furnace to the stat..... you could use a 24vAC relay or the fan center relay to directly control the burner. If you'd like to use the fan center..... turn the power off, take the plate off and post a few pictures of the wiring.
That doesn't look like a three wire thermostat cable.
So much for things being easy! When you say I can use a 24vAC relay or the fan center relay: do you mean with this Nest E thermostat, or, would I have to get the Nest 3? I was hoping to use this one, as I only paid a little over $100 for it vs $249 for the Nest 3, but, if I have to get a Nest 3, I will.
Here's some pictures of the Fan Center wiring:
I have some 18/5 thermostat wire that I'm going to replace the 2 wire with, so, that wiring shouldn't be an issue.
Thanks Again!
Bruce
Last edited by PJmax; 12-16-19 at 05:19 PM.
Reason: resized pictures
Your pictures are excellent. We can do what we need. I'll be back later to explain it.
This is so weird. Working with two members at the same time with similar equipment. In the other thread the member has the same seemingly unused fan center.
Wow! That's crazy: the furnace pictured in post #10 of that thread looks almost exactly like mine! I have a Trane XP80, although it appears the insides are shared between companies.
beckett 7505 trying to hook up a ecobee 4 WiFi thermostat
I also have a beckett 7505 trying to hook up a ecobee 4 WiFi thermostat would this setup also work for me . I don’t have a/c or fan, just a oil burning furnace . Only have two wires W and R missing C
You either need to add a 24vac transformer and a relay OR a fan center OR the Beckett kit.
The PEK kit that comes with the Ecobee should allow it to run in two wires but I don't recommend it.
I highly recommend running a new cable.
Not one for raising the dead but this covered 95% of my issues, only problem is my Ecobee SmartThermostat isn’t coming on. I have the same burner with what I believe is a fan center that has a G wire running to the t stat. The burner just has the tt wiring direct to t stat. I connected everything in the same manner and ran a previously unused wire from C on the fan center terminal to C on the t stat. Unfortunately, no joy. I’ve been doing as much research as I can about how all of this functions but it’s definitely not my area of expertise. As I understand the tt wiring completes a circuit to say furnace on, and the g wire controls the fan. Any help is appreciated.
The only way I would connect that system is to use a basic single pole 24vac relay.
Any single pole 24vac relay would work. Choose one from below or pick your own.
Once you've committed to a relay I'll draw the easy to follow wiring.
Something doesn't look right there.
Typically the blower (G) needs to get switched to R not C.
Can you tell me how the wiring is/was connected to the existing (old) stat ?
This would be standard wiring..........
Red to R
Black to C
Green to G
Yellow to relay terminal #1
Relay terminal #3 to C.
Last edited by PJmax; 10-03-21 at 10:54 AM.
Reason: white changed to yellow wire
This is a stand alone post. This is the way it should technically be wired.
stat ------> color ------> furnace
R --------> Red ----------> R
C --------> Black --------> C
G -------> Green --------> G
W1 -----> Yellow --------- to relay terminal #1
Relay terminal #3 to C.
Relay 2 and 4 to TT terminals.
Good job. Thanks for letting us know how you made out.
This thread is pushing the limit of viewable threads. It will be closed but it will remain in our searchable archives for viewing. If this thread doesn't answer your questions.... start a new one and reference this one.
I am swapping out a Honeywell TH621OU2001 thermostat for a GoControl GC-TBZ48 smart thermostat at a new home we just purchased to make an airbnb. We use the same GoControl thermostats at all of our Airbnb's and I have installed dozens of them. We chose GoControl because we have a couple houses without C wires and this is the best smart thermostat that doesn't require the common wire, maybe the only.
This home is all electric and the system is a Goodman Aruf31b14ac.
I believe my problem is with the brown wire, but I could be wrong. This is the only all electric/heat pump system I have, it's just not that common in my area. The old thermostat Wiring, new thermostat options, the way I have the new thermostat currently wired and the wiring inside the air handler are pictured.
With my current wiring, I can not get the heat, cool, emergency heat or the fan to kick on. I did shut off power to the unit before wiring, so do not believe it is a fuse, which I have done before. I also checked continuity in the wiring, but I didn't figure that was an issue since it functioned fine before changing thermostats.
Does anyone have any suggestions on the correct wiring for the new thermostat? I am sure it is something simple I am overlooking.
Thank you.
[img]https://cimg4.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/pxl_20211002_190344373_8d42769bfda1ec812fe72d9e366847fd279bf652.jpg[/img]
[i]Old thermostat model info. [/i]
[img]https://cimg7.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/pxl_20211002_190126239_8237e1e548e5e33b399e89f33bf3b122872cadd5.jpg[/img]
[i]Old thermostat without wiring for description reference. [/i]
[img]https://cimg8.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/pxl_20211002_173939515_75d7136911bf268bb5a3bdbb96d79d97565588be.jpg[/img]
[i]Old thermostat Wiring. [/i]
[img]https://cimg3.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/16332023470948640680657630703696_7be80871689467be436d0555c455b07e624a82cf.jpg[/img]
[i]New thermostat Wiring diagram. [/i]
[img]https://cimg9.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/pxl_20211002_190103073_208ac982a1924122f473d855040d7b37e035ff37.jpg[/img]
[i]New thermostat wired. [/i]
[img]https://cimg0.ibsrv.net/gimg/www.doityourselft.com-vbulletin/2000x1504/pxl_20211002_191315072_92a84c1c7680502c6d86c38162cf0fafc5901adb.jpg[/img]
[i]Air handler wiring. [/i]
I have three Trane XL824 thermostats in my home but have never, until now, had to open one. I was doing something about three feet above the thermostat and dropped a very tiny screw which, of course, fell into one of the vents in the top of the XL824. I REALLY need that screw! I cannot find anywhere how to remove the front unit from the back plate. I can find installation videos where I see that there are four snap connectors in the corners of the back plate which engage the front unit. I know I have to turn the power off to the unit but how do you get the thermostat off the back plate. I can't see any tabs etc which can release those snaps. Any help is greatly appreciated.
02-09-19, 03:24 PM
Solved! Nest Thermostat installed!
