New thermostat, boiler will not shut off

My system consists of cooling via a Rheem central air handler and heating via a Williamson boiler with radiators. It was working just fine until I replaced my Pro1 thermostat with the wyze, installed with the C-wire adapter, and now the furnace will not shut off.

The AC goes on and off at the appropriate temperatures, so no problems there, but the boiler is set on burning the place down. I had to shut it all off until I figured out that keeping the emergency shutoff and the gas feed valve shut will keep the boiler from turning on (although it keeps trying every few minutes, you can hear it trying to start the pilot).

The moment I open up that valve and flick the emergency shutoff switch that boiler goes back to full bore, meanwhile the wyze thermostat seems to have no idea this is happening.

Please help. I can provide photos of all wiring pre and post

Yep, I will need wiring photos. You probably bypassed an end switch when you installed the C adapter, but photos will tell me for sure, and how to fix the problem, it would also be greatly helpful if you took any photos before hooking anything up in the air handler, if you could share those.

I can only post one photo at a time

The wiring at the air handler is obviously a mess, but I traced the wires from the original thermostat to wherever they were spliced and marked them as you can see. AC works fine now, so I believe I traced everything properly, except there must be an issue with Rh and W1 since the boiler runs non-stop.

The original wiring setup at the handler is essentially what is shown on the photograph except without the C-wire adapter. Before wiring the adapter, W1 was going from thermostat to splice with a white wire going to the boiler. I left Rh spliced to exactly where it was (a red wire going to boiler). The red wire and the white wire going to the boiler are part of the same cable.

This setup worked just fine with original Pro1 thermostat, AC would turn on and off when appropriate, and boiler would turn on and off when appropriate.

Hmm, with that rats nest of wires, I’m going to need you to do some diagnostics on your end to figure this out.
First try this: Find the W wire that comes out of the boiler, and the W wire that goes into the C adapter terminal and connect them directly, without the C adapter in the middle.
Cap off the W ribbon cable wire from the C adapter.

A quick question first: when you set up your thermostat, you did make sure to tell the thermostat that you had the following wires, correct?
Rc, Rh, G, Y, W

Yes, those are the wires I identified to the thermostat

I’ll try that test now

So I connected the W from boiler and W from thermostat, capped the lone W lead from adapter, and the boiler turns on full bore, while thermostat settings are currently set to off. Boiler remained this way for 10 minutes at which point I shut it off at the emergency shutoff and cut the valve because I really don’t want heat right now…

Also another test I did was to leave the entire system on (gas valve off) and pull the wyze out of the back panel to see if the cause is at the thermostat or if the circuit is somehow being completed downstairs in the basement before the wires ever reach the thermostat, but the boiler didn’t try turning on once I pulled the wyze, and it would try turning on when I put the wyze back in so I don’t think it’s a short circuit downstairs, unless it is a short downstairs of the W wires that still requires the Rh upstairs to be landed in the thermostat….

So, that eliminates the C adapter as your problem. You might have a faulty thermostat.

To test this, connect the W wire from the thermostat to the G wire that comes out of the furnace. That is, disconnect the ribbon cable that runs from the C adapter that is marked G from the green wire that comes from your furnace, and connect the W wire to the green wire that you just disconnected. Do not connect the W wire to the G/C wire that goes to the thermostat or you will create a short circuit.

If the fan starts running immediately, then your thermostat’s heat relay is stuck in the on position, and you will need to contact support and RMA your thermostat.

The fan does not start… now I’m not sure what to troubleshoot next other than there must be a short between the boiler W and Rh wires some where in the basement. Unless there’s some sort of setting on my boiler to make it such that it can be controlled by the thermostat as opposed to it being on all the time

Can you open the furnace/ boiler top panel and take a picture of the inside?
also clearly differentiate where the RC and Rh wires are coming from in your basement? i can see that the Rh wire comes from the boiler/furnace, but where is the Rc wire coming from?



Rc wire comes from the condenser outside

Do you have a multimeter?
If you do, take off Rh and W1 and check for continuity between them when the thermostat is on, but heat is off.