4.3 Using the Room Thermostat for Specific Applications

The CM927/921 RF room thermostat is a versatile controller that can be used to control many different applications. For most typical applications, like wall-hung gas fired combination boiler control or zone valve control, no adjustments from the factory settings are required. For other applications, like controlling an oil burner, the best system performance can be achieved by modifying selected parameters of the room thermostat in the Installer mode. The table below lists the most common settings used for specific applications.

Specific Application:

Setting:

 

What to change:

 

 

 

 

 

 

 

 

 

Cycle/

Minimum ON

Note: All parameters listed below belong to category 2

 

 

Hour

Time

- System Parameters (see Installer Parameters Table)

 

 

 

 

 

 

 

HEATING

Gas Boiler (<30kW)

6

1

No changes required

 

 

 

 

 

 

 

 

 

 

Oil Boiler

3

4

Set 1:Ot parameter to 4

 

 

 

 

 

 

Set 2:Cr parameter to 3

 

 

 

 

 

 

 

 

 

 

Thermal Actuator

12

1

Set 2:Cr parameter to 12

 

 

 

 

 

 

 

 

 

 

Zone Valve

6

1

No changes required

 

 

 

 

 

 

 

 

AIR-

 

 

 

To enable switching between cooling and heating

 

CONDITIONING

 

 

 

modes adjust parameter 4:HC in category 2 (0 =

 

 

 

 

 

disabled, 1 = enabled). Now you can switch between

 

 

 

 

these modes by pressing the

and buttons

 

 

 

 

 

together for 5 seconds in any of the product operating

 

 

 

 

modes (AUTO, MAN or OFF). Explain to the end user

 

 

 

 

how to switch between these modes using the

and

 

 

 

 

buttons and ensure the cooling program is modified

 

 

 

 

as required.

 

 

 

 

 

 

 

 

 

 

Heat Pump / Air-

3

4

Set 1:Ot parameter to 4

 

 

 

Conditioner

 

 

Set 2:Cr parameter to 3

 

 

 

 

 

 

 

 

 

 

Fan Coil

6

1

No changes required

 

 

 

 

 

 

 

 

 

4.4 Using the Special Features of the Room Thermostat

Special Feature:

Description:

Enable/Disable

 

 

 

Optimisation

The thermostat will adjust the start time in the morning/afternoon so the

To enable: Set parameter 8:

(Variable Start

desired temperature is reached by the start of the program period. The

OP (category 1) to 1.

Time)

system will restrict the start time to a max of 2 hours.

 

 

 

 

Heating or Cooling

This product can be used for heating or cooling applications. If you select

To enable: Set parameter 4:

Operation

cooling mode the control algorithm and factory default program will be

HC (category 2) to 1.

 

modified. You can independently modify the heating and cooling profile.

 

 

 

 

Summer/Winter

This feature moves time automatically on the last Sunday of March and

To enable: Set parameter 3:

Auto time change

the last Sunday of October. The feature is factory enabled.

tC (category 1) to 1.

 

 

 

Temperature Offset

If the thermostat is located in a particularly hot/cold location for reliable

Set parameter 12:tO

 

signal transmission reasons then the measured/displayed temperature

(category 1) to the required

 

can be adjusted by +/- 3°C. This is useful if the homeowner wants the

offset value.

 

reading to match another appliance temperature display.

 

 

 

 

Upper/Lower

The normal upper temperature limit of 35°C can be reduced to 21°C

Set parameter 6:uL (category

Temperature Limit

to save the homeowner energy. The normal lower limit of 5°C can be

1) to the desired upper limit.

 

increased up to 21°C to protect inhabitants from cold.

Set parameter 7:LL (category

 

 

 

 

1) to the desired lower limit.

 

 

 

8

CM900 Wireless - Programmable Room Thermostat

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Honeywell CM900 Using the Room Thermostat for Specific Applications, Using the Special Features of the Room Thermostat
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CM900 specifications

The Honeywell CM900 is a sophisticated programmable room thermostat designed to enhance energy efficiency and ensure optimal comfort in residential settings. This device is characterized by its advanced features, which cater to the increasingly demanding needs of modern households.

One of the standout features of the CM900 is its intelligent programming capabilities. Users can easily set different heating schedules for weekdays and weekends, allowing for personalized comfort that adapts to the household's routine. This programmable functionality not only maximizes comfort but also contributes to energy savings, as it can automatically lower the heating during unoccupied periods.

The CM900 is equipped with a user-friendly interface that makes it straightforward to adjust settings. The large, clear display provides essential information at a glance, such as current room temperature and set points. Additionally, the intuitive menu navigation allows users to customize settings quickly, ensuring a seamless experience even for those who may not be technically inclined.

Incorporating the latest technology, the Honeywell CM900 features an innovative adaptive control system. This technology enables the thermostat to learn the heating characteristics of the home, adjusting pre-heat times to ensure that the desired temperature is reached precisely when needed. As a result, users can enjoy comfortable living spaces without wasting energy.

The CM900 also boasts an impressive response time, ensuring that any adjustments to the heating system occur swiftly. Coupled with precise temperature sensing, this allows for a stable indoor climate, which is essential for both comfort and energy efficiency. The device can be connected to various heating systems, making it a versatile option for a range of home heating configurations.

For those interested in further customizing their heating experience, the Honeywell CM900 offers compatibility with multiple accessories, including remote sensors and Wi-Fi connectivity options. This enables homeowners to monitor and adjust their heating systems even when they are away from home, leading to added convenience and peace of mind.

In summary, the Honeywell CM900 is a high-performance programmable thermostat that combines advanced technology with user-centric features. Its intelligent scheduling, adaptive control, and ease of use make it an excellent choice for anyone looking to achieve a perfect balance between comfort and energy efficiency in their home.
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