Installing Honeywell Programmable Thermostat Two Wires

How to Install a WiFi thermostat without C wire. If you don’t have a common wire and want to install a smart thermostat, you still have quite a few options. Option 1 is to buy a smart thermostat that doesn’t require a C wire. The Sensi and Ecobee are two top models that don’t require a common wire.

Note: This article is scheduled for a complete re-write. In the meantime, the following Q and A may address a very common issue.

Q: I installed my new programmable thermostat, but it won’t turn on.

A: If you plan to upgrade to a new thermostat make sure you have the proper number of wires available, otherwise your new thermostat won’t work (most advanced Honeywell thermostats require a common (C) wire to power on). If you do need additional wires, you will want to consider how difficult installing new wires will be for your application, and if you need to budget for an electrician or HVAC tech to install the proper wiring.

4 Wire Honeywell Thermostat Wiring

  • G – Fan (green wire)
  • R – 24 VAC / Rc and R or Rh (red wire)
  • Y – Compressor / air conditioner (yellow wire)
  • W – Heat (white wire)

Note: The living end дискография скачать. A previous installer may have used a different set of color wires. This will be a non issue to keep track of if a whole new set of thermostat wires is pulled. Otherwise tag the wires before removing from the existing thermostat, or take note of the terminals each wire is attached to.

NOTE: This article provides the basics of what to expect and look for when wiring a new or existing thermostat. With the many brands and models of thermostats existing, along with the numerous issues that could arise with corresponding devices, we suggest contacting the thermostat manufacturer technical department or have a professional local service tech do an inspection of your system if not operating properly.

Installing honeywell programmable thermostat two wires

5 Wire Honeywell Thermostat Wiring

Some programmable thermostats (e.g. Honeywell Prestige wiring requirements) need a minimum of 5 wires, and maybe more depending on what features you want to operate (humidifier, etc). The additional 5th wire will be for common; providing stepped down power from a transformer.

  • G – Fan (green wire)
  • R – 24 VAC / R and Rc (red wire)
  • C – 24 VAC Common (color can vary per manufacturer – may be blue, purple, brown. etc.)
  • Y – Compressor / air conditioner (yellow wire)
  • W – Heat (white wire)

Furnace Electrical Board Connections

Going into your furnace may sound intimidating, but if you have the basic knowledge of wiring, and know how to remove the proper furnace panels to access the electronics, then you should be fine. The COM 24V terminal will be connected to the C (24 VAC common) of the thermostat.

How to Install Thermostat Wire

If you have easy access to the existing thermostat wires, just remove and follow the same path with the new set of wires. You can use cable ties, electrical tape, or staples. Be sure to take a very conservative measurement on how long your new set of wires should be. You don’t want to start over, if you come up short.

Install Honeywell Non Programmable Therm…

Any home improvement store should carry thermostat wiring. Also check local electrical and lighting supply houses.

Honeywell 2 Wire Thermostat

If wires pass through a floor and up into a wall cavity before reaching a thermostat. Try the following.

  • Start at the thermostat location. (i) A simple trick for pulling new wires to replace existing ones: tape one end of the new wires to the end of the existing wires coming through the electrical box or wall opening. Make sure to tape completely over the wire ends, so no edges are present that can snag something. (image below)
  • Slowly pull the new set of the wires down through the wall from the basement. (i) Use any object larger than the hole in the wall, and tie or fasten to the end of your new wires, so you don’t pull all the wire through the wall. e.g. pencil or flat washer, to act as a stop. Use electrical tape to secure if necessary.

Installing Honeywell Programmable Thermo…

In a situation where the original thermostat wires may have been stapled to an interior wall stud, and not run through conduit, you may be better off leaving the existing set of wires, and cutting them off at the entry and exit points of the wall. Then feed new wires with a fish tape (Klein Tools). Check your local home improvement stores, or local tool rental, for rental availability.