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Honeywell rth230b Installation And User Manual

Programmable electronic thermostat.
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1. Introduction
The RTH230B programmable thermostat can be used to control:
• a gas, fuel oil or electric furnace - 2 or 3 wires
• a central air conditioner - 2 or 3 wires
• a hot water system with or without pump - 2 wires
• a millivolt system - 2 wires
• a central heating and cooling system - 4 or 5 wires
Note: These thermostats are not compatible with heat pumps or
multi-stage systems.
System operating
mode selector
• System operating mode selection: heat, cool or off
• Fan operating mode selection: automatic or on (continuous)
• Programmable heating and cooling cycle lengths: 10, 12, 15, 20
or 30 minutes
• Temperature display in °F or °C
• Battery replacement indicator
- Preprogrammed energy-saving schedule
- Early Start
- Temporary bypass
- Time display (12 h or 24 h)
• Filter replacement indicator
2.1 Removing the Old Thermostat
Remove the old thermostat to access the wires.
Warning: If the old thermostat was mounted onto an electrical box,
it was probably powered by 120/240 volts. In this case, this thermo-
stat cannot be used.
Identify and label each wire (with the corresponding letter on
the wire terminal) and remove them from the terminals.
If necessary, strip the end of each wire (maximum of 1/4 inch).
Programmable Electronic Thermostat
Installation and User Guide
Fan operating
mode selector
Wrap the wires around a pencil to prevent
them from falling into the wall.
If the hole in the wall is too big, insulate it
using a non-flammable material in order to
avoid air draughts behind the thermostat.
2.2 Installing the New Baseplate
For a new installation, choose a location approximately 5 feet
(1.5 m) above the floor and on an inside wall. Avoid draughty
areas (top of staircase, air outlet, etc.), dead air spots (behind
doors), direct sunlight or areas near concealed pipes or chim-
Remove the thermostat faceplate.
Loosen the locking screw to separate the thermostat from its
baseplate (the screw cannot be completely removed).
Tilt the thermostat upwards.
Mark and bore the appropriate mounting holes (or use the
existing holes). Insert the plastic anchors.
Pass the wires through the opening of the baseplate and fix the
baseplate to the wall using the screws provided.
2.3 Connecting the Thermostat
The connection of the new thermostat should be similar to that of
the old thermostat; however, it can vary depending on the installa-
Note: The red jumper wire between the Rc and Rh terminals must
be removed in 2- or 5-wire installations. The jumper must be used in
3- or 4-wire installations if you wish to use the mode selector switch
for the fan.
Heating power supply
Cooling power supply
Heating signal
Cooling signal


   Summary of Contents for Honeywell rth230b

  • Page 1: Installation

    Programmable Electronic Thermostat Installation and User Guide 1. Introduction The RTH230B programmable thermostat can be used to control: • a gas, fuel oil or electric furnace - 2 or 3 wires • a central air conditioner - 2 or 3 wires •...

  • Page 2: Basic Functions

    (HEAT) or Cooling mode (COOL), or to set the system off. Note: When you place the thermostat in Cooling mode, you might need to wait up to five minutes before cooling can start. This is a safety feature for Fan relay the compressor.

  • Page 3: Programming, Configuration Menu

    2 hours. The house icon flashes during the bypass. At the end of the bypass period, the thermostat returns to the temperature settings of the period currently underway.

  • Page 4: Specifications

    This warranty does not cover removal or reinstallation costs. This warranty shall not apply if it is shown by Honeywell that the defect or malfunction was caused by damage which occurred while the product was in the possession of a consumer.

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  • ralph Nov 15, 2017 05:55:
    this thermostat is virtually impossible to program. it is a piece of junk.
  • Kathy mCcREARY Nov 15, 2017 04:32:
    I tried the instructio​ns and when I program it keeps flashing I do not understand how to make my program stay. Also I have tried calling many times and always get same results call back high volume of calls My thermostat is RTH23OB
  • Ruthie Holtorf Feb 27, 2017 10:28:
    I just bought a house with this thermostat in it--and I have changed the filter on it already Brand new one, but the word FILTER is still showing up. What can I do to get it to shut off as it is a NEW filter. I would appreciate any help you can give me on this.
  • gary Dec 19, 2016 02:01:
    This is without a question the crappiest thermostat made
  • dean covey Nov 23, 2016 05:37:
    The manual for the rth 230b was EXACTLY what i needed and very valuable.
    ​Thank you so Much!