Honeywell CM927



The Honeywell CM927 is a wireless programmable thermostat that is designed for use in domestic and light commercial heating systems. It is a popular choice for homeowners and installers due to its flexibility, ease of use, and energy-saving features.

Some of the key features of the Honeywell CM927 include:

  1. Wireless operation – The CM927 uses radio frequency (RF) signals to communicate with the receiver unit, giving you more flexibility in terms of where you can install the thermostat.
  2. 7-day programming – The unit allows you to set different heating schedules for each day of the week, providing flexibility and energy savings.
  3. 6 time and temperature settings per day – The CM927 allows you to set up to six different temperature settings for each day, giving you greater control over your heating system.
  4. Large backlit display – The CM927 features a large, easy-to-read display that shows the current temperature, the time, and the status of the heating system.
  5. Pre-set heating schedules – The CM927 comes with pre-set heating schedules that can be easily customized to suit your specific needs.
  6. Holiday mode – If you’re going away, the CM927 can be set to holiday mode, ensuring that your heating is turned off while you’re away.
  7. Frost protection – The CM927 has a built-in frost protection feature that will turn on the heating if the temperature drops below a certain level, preventing pipes from freezing.

Overall, the Honeywell CM927 is a reliable and user-friendly wireless programmable thermostat that can help you save money on your heating bills while keeping your home comfortable.

How to operate

  1. Ensure that the receiver unit is installed and wired correctly to your heating system.
  2. Install the batteries into the thermostat.
  3. Press and hold the ‘PROG’ button for 3 seconds to enter the programming mode.
  4. Use the ‘+’ and ‘-‘ buttons to select the day of the week you want to program. Once you have selected the day, press ‘PROG’ again.
  5. Set the ‘ON’ and ‘OFF’ times for each temperature setting using the ‘+’ and ‘-‘ buttons. Once you have set the times, press ‘PROG’ to move onto the next time period.
  6. Repeat this process for each temperature setting for each day of the week until you have set your complete schedule.
  7. Once you have set your schedule, you can use the ‘+’ and ‘-‘ buttons to adjust the temperature settings for each time period.
  8. If you need to override the schedule and turn the heating on outside of the programmed times, simply press the ‘Override’ button until the heating comes on. To turn it off again, press the ‘Override’ button again.
  9. To enter holiday mode, press and hold the ‘Prog’ button for 3 seconds. The CM927 will then switch to holiday mode, turning off the heating until you return and switch it back to normal mode.

That’s a basic overview of how to operate the Honeywell CM927. For more detailed instructions, you should refer to the user manual that came with your unit.


Sending a binding signal.

Before the wireless programmer will work, you will need to send a binding signal to the wireless relay box…

Operating the CM921 or CM927

Technical information

Central heating control typeWireless programmable thermostat
Heating system compatibilityCompatible with most gas, oil and LPG boilers
Control operation7 day, 5/2 day or 24 hour programming
Temperature control range5°C to 35°C
Operating temperature range0°C to 40°C
Display typeLarge, easy-to-read LCD screen
Hertz (Hz)Designed to operate on a 230V AC, 50Hz power supply.
Switch ratingThe CM927 does not have a switch rating as it is not a switch, but a thermostat.
Max. load (Inductive)The CM927 does not have a maximum load rating specifically for induction loads.
Instead, the maximum load rating for the CM927 thermostat is 230V AC, 50Hz, 3A resistive, 1A inductive. This means that the thermostat is capable of controlling a maximum load of 690W (resistive load) or 230VA (inductive load).
Max. load (Resistive)See directly above.
Power consumptionApproximately 0.3 watts when the backlight is off and 1.8 watts when the backlight is on.
Dimensions90mm x 130mm x 27mm (H x W x D)
Battery2 x AA alkaline batteries
Programmer Voltage230V AC
Smart compatibilityThe CM927 wireless programmable thermostat is not considered a “smart” thermostat, as it does not have internet connectivity or the ability to connect to other smart devices in the home. However, it is designed to be compatible with a range of Honeywell wireless communication devices, such as the BDR91 relay box, to provide control of the heating system remotely.
Terminal capacityThe CM927 wireless programmable thermostat has two terminal blocks for connecting to the heating system. Each terminal block has a capacity of up to 1.5 mm² wire diameter, which is roughly equivalent to 16 AWG wire size. The terminals are designed to accept stripped wires or wires terminated with spade or fork connectors.
It is important to note that the CM927 is designed for use with low-voltage heating systems, typically operating at 24V AC. If you are unsure about the compatibility of your heating system with the CM927 thermostat or need assistance with wiring, it is recommended to consult a qualified HVAC technician or electrician for proper installation and usage guidance.

User guide