Upgrading my Thermostat to wifi without C wire / Using switch relay with internal transformer
Hello!
I moved into a house with steam radiators run off an oil burner. I'd love to upgrade to a wifi thermostat that would require a C wire for power. I bought this universal relay with internal trasnformer to help resolve the issue of not having a C wire availability to connect to my Ecobee thermostat.
https://www.supplyhouse.com/Resideo-R8845U1003-Universal-Switching-Relay-w-Internal-Transformer
Does this wiring look correct?
This is to the universal switching relay with internal transformer
This is the wiring to the Ecobee thermostat:
Tied the two R/W wires to the Carlin TT slots. Power is coming from the L1/L2 lines, but no power coming to the thermostat.
Any considerations are welcomed! TY in advance
Comments
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How's that 1 amp fuse looking?
1 -
wiring looks correct,
did you check that fuse?
known to beat dead horses0 -
thanks for the suggestions… just checked it and the fuse is working…
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Jump R to W in the Honeywell. If the relay clicks, check your wiring & Nest (we just condemned a Nest with a defective subbase in a different thread). If it doesn't, you don't really have power to the Honeywell or it's defective.
1 -
I appreciate you helping me out! I will try…
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it clicked so the Honeywell is working… I will recheck wiring… but so far no luck
0 -
clicking doesn’t mean the contacts opened / closed.
1 -
It looks right. The red and white from X1 & X2 on the relay go to the burner T & T correct??
0 -
Does the Green 'Call for Heat' LED ever light up ?
What happens when you push the square Red 'Test' button ?
Cables mixed up ?
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Try using terminals A & B. They switch at the same time as X1 & X2.
You can check X1 & X2 by removing the wires & checking for continuity/resistance. Should be continuity/low resistance (≈<1Ω) with a heat call and no continuity/open circuit (OL etc.) with no heat call.
1 -
Yes, they do.
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I know the Ecobee thermostat works because I tested it on my AC unit that already had a built in C wire… May end up running it from there and connecting AC/heat units from that?
It is bothering me why I cannot get this relay to work though…
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Not on it's own, but when I press the red test button it blinks green.
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Yes
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Well when the Red test button is pressed it mimics a contact closure between the R(T) & W(T) (a thermostat call for heat). When you press the Red button and hold it briefly the Green 'Call for Heat' LED should light up and you should hear the relay(s) click and the boiler should start.
If you jumper R(T) & W(T) the Green 'Call for Heat' LED should light up you should here the relay(s) click and the boiler should start. If not try just jumpering the wires connected to X1 & X2, the boiler should start.
Even if the boiler was disconnected a call from the thermostat should activate the Green 'Call for Heat' LED and energize the relays.
Again, I suspect the multi wire cables are reversed. Or something was damaged in the transition.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System1 -
Thank you for taking the time for a thoughtful response. I will recheck this tomorrow! I appreciate you.
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Also.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Not the relay I would have selected for this job. But since you already own it this is how to connect the wires.
Tied the two R/W wires to the Carlin TT slots. Power is coming from the L1/L2 lines, but no power coming to the thermostat.This statement sounds like this.
I know that this will not work
I believe you have it wired this way by the looks of the wires in your photo.
I know the Ecobee thermostat works because I tested it on my AC unit that already had a built in C wire… May end up running it from there and connecting AC/heat units from that?It is bothering me why I cannot get this relay to work though…
Does the same thermostat operate the air conditioner and the heat? In the thermostat subbase photo, it appears that you have heat only wires
Areyou sure that you have the proper common wire connected?
Edward Young Retired
After you make that expensive repair and you still have the same problem, What will you check next?
0
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