Deprecated Honeywell Thermostats

This page documents 3 Honeywell thermostats that were previously installed in the Gelb Building. They are either no longer used or are in the process of being replaced by smarter Matter-compatible thermostats that can be integrated into our Home Assistant.

Important: we're not certain this information is correct! Supposedly there are 2x cooling and 1x heating thermostats, but which one is which??

Front Cooling Thermostat

The front Honeywell thermostat, nearest to the staircase.

Internal wirings of the front Honeywell thermostat.

This thermostat sits near the staircase in the front of the building.

We were told that it was a cooling thermostat, but this isn't confirmed (see C-wire explanation below).

The C wire of this thermostat was not working at the time the new smart thermostat was installed, even with the 2 "ROOF UNIT" breakers on. This might be due to some tripped fuse/breaker on the AC unit itself, or it might actually be a heating thermostat, since the heating unit was shut off at the time of installation. We can't actually compare this to the Back Heating Thermostat, since that one is powered via batteries.

This unit was powered by 2x AA batteries. It might have been functioning without a working C wire at all this whole time, which would suck.

Back Cooling Thermostat

The back Honeywell thermostat, near the kitchen doors.

Internal wirings of the back Honeywell thermostat.

This thermostat sits near the kitchen doors on that side of the hallway.

This should definitely be the cooling thermostat. It turns on when the "ROOF UNIT" breakers are on, and it seems to turn on the hallway ACs. We're not sure if it's only supposed to cover the backside of the hallways or if it handles the entire space. There are 2 cooling thermostats (allegedly), so presumably the former is the case.

An oddity that was kept was how there are 2 C wires coming out of the electrical box. These wires were bridged together in the same screw socket of the thermostat, so it was kept like that using a 3-slot wago. We suspect that one of the C wires is daisy-chained to the front thermostat, but if there are 2 separate cooling units, then this wouldn't make much sense?

Back Heating Thermostat

Internals and backside of the third Honeywell thermostat.

Internals of the Honeywell thermostat backplate with the front of the thermostat itself in picture.

This thermostat sits on the SCN side of the hallway. It can be found somewhat near the Back Cooling Thermostat.

It appears to be a heating thermostat, as we were told. The fact that only the R and W wires are connected may support this?

The Honeywell thermostat is currently powered by 4x AA batteries. This specific spot seems to lack a C wire, which would prevent us from installing a smart thermostat here.