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This device works alongside home heating and cooling systems. It connects with low-voltage wiring to help the control system sense indoor air conditions.
Specifications
- Part number: C7189U1005
- Brand: Honeywell
- Part type: Thermostat
- Dimensions: 1.50 x 0.75 x 2.25 in (W x D x H)
- Material: Plastic housing with ventilated cover
- Wiring: Hardwired (S1/S2 terminals)
- System: gas, electric or heat pump, as listed
- Stages: heat and cool stages your system uses
- C wire: needed by some models, check yours
From the maker's and parts sellers' listings for this number. Compare them with the label on your old part.
What the Part Does
A thermostat component monitors indoor air conditions and communicates with your central system. Most central heating and cooling systems use a 24 V control signal from a transformer to manage calls for heat or cool.
When connected to your system, the unit helps report temperature data back to the central controller. This helps your equipment run when heating or cooling is needed.
Understanding the Specifications
Reviewing the listed specifications helps ensure you have the correct item for your physical mounting space and wiring setup.
- Dimensions: 1.50 x 0.75 x 2.25 in (W x D x H)
- Material: Plastic housing with ventilated cover
- Wiring: Hardwired (S1/S2 terminals)
How to Confirm Match
Before changing components, compare the details of your existing unit to this part number. Central systems commonly rely on 24 V controls, while electric baseboards use line voltage. These are not the same, so check your system type carefully.
- System type: check whether your system is gas, electric or heat pump, as listed.
- Stages: verify the heat and cool stages your system uses.
- C wire: check if a common wire is needed by your setup.
- Wiring connections: ensure your installation uses Hardwired (S1/S2 terminals).
Signs of Failure and Safe Replacement
A thermostat component may need replacement if the control system stops responding correctly to room temperatures or fails to read values across its wiring terminals. Follow safe installation procedures when replacing a unit.
- Shut off the furnace or air handler at its switch or circuit breaker.
- Remove the cover and take a photo of every wire before removing the old part.
- Carefully disconnect the wires from the terminals.
- Mount the replacement housing in place.
- Move wires one at a time to the matching spots on the replacement part.
- Restore power at the breaker or switch.
Read your old part
- Locate the label or stamp on your existing part housing.
- Check the part number on the label to verify it matches C7189U1005.
- Confirm the terminal markings on your old unit match Hardwired (S1/S2 terminals).
- Check the dimensions of your installation area against 1.50 x 0.75 x 2.25 in (W x D x H).
When to call a pro
Hire a licensed HVAC technician for any step you are not sure you can do safely. If you encounter line voltage wiring or are unsure about your control board connections, let a professional complete the work.
Questions
What wiring does the C7189U1005 use?
This part uses Hardwired (S1/S2 terminals). Always take a photo of your existing wires before removing anything from the wall.
What are the dimensions of this part?
The dimensions are 1.50 x 0.75 x 2.25 in (W x D x H). It features a plastic housing with ventilated cover.
What voltage do most home thermostats use?
Most home thermostats use a 24 V control signal from a transformer. Baseboard heaters use line voltage, which is not the same.
What should I do before disconnecting the wires?
Turn off power to the furnace or air handler at the breaker or service switch. Take a clear photo of which wire goes to which terminal before you remove anything.
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