RT520 Thermostat - Full User Manual

1. Introduction

1.1 Product Compliance

This product complies with the essential requirements and other relevant provisions of Directives 2014/53/EU and 2011/65/EU. The full text of the EU Declaration of Conformity is available at the following internet address: www.saluslegal.com.

1.2 Safety Informations

• Before starting installation work and before using the product, read the entire manual.
• The information contained in the instructions is essential for proper functioning.
• To avoid accidents resulting in personal injury and material damage, please follow all safety precautions, specified in this manual.
• The device should not be used by people with limited mental, sensory or mental abilities, without experience, of insufficient knowledge as well as children.
• Do not use an unassembled device (e.g. without a cover).
• The device may only be opened by a qualified person.
• Keep electrical devices out of the reach of children and ensure that they do not play with it. Children should not be left unattended. If necessary, disconnect the control system for the entire room.
• Do not leave the packaging, cabinet, or any loose parts of the device unattended, as they pose a risk to children.

WARNING! Installation must be carried out by a qualified person with appropriate electrical qualifications in accordance with standards and regulations in force in the given country and in the EU.

• Never try to connect the device other than as described in the manual.
• Before assembly, repair or maintenance as well as during any connection works it is absolutely necessary to disconnect the mains supply and make sure that the terminals and electric wires are not live.
• The device may not be exposed to extreme temperatures, strong vibrations or subjected to mechanical shock.
• The device should not be used in unfavorable environmental conditions or in rooms where there is a concentration of flammable gases, fumes or dust.

WARNING! There may be additional protection requirements for the entire installation that the installer is responsible for maintaining.

Care for the natural environment is of paramount importance. The awareness that we manufacture electronic devices obliges us to dispose of used electronic components and devices safely. Therefore, the company has received a registration number issued by the Chief Inspector for Environmental Protection. The crossed-out symbol of a trash can ?️ on the product means that the product must not be disposed of with ordinary waste containers. Sorting waste for recycling helps to protect the environment. It is the user's responsibility to surrender used equipment to a designated collection point for recycling waste from electrical and electronic equipment.

2. Product Overview

The RT520 room thermostat simply switches the heating system on and off as necessary. It works by sensing the air temperature, switching on the heating when the air temperature falls below the thermostat setting, and switching it off once this set temperature has been reached.

Turning a room thermostat to a higher setting will not make the room heat up any faster. How quickly the room heats up depends on the design of the heating system, for example, the size of the boiler and radiators. Neither does the setting affect how quickly the room cools down. Turning a room thermostat to a lower setting will result in the room being controlled at a lower temperature, and saves energy.

The heating system will not work if a time switch or programmer has switched it off.

The way to set and use your room thermostat is to find the lowest temperature setting that you are comfortable with, and then leave it alone to do its job. The best way to do this is to set the room thermostat to a low temperature – say 18°C – and then turn it up by one degree each day until you are comfortable with the temperature. You won't have to adjust the thermostat further. Any adjustment above this setting will waste energy and cost you more money.

If your heating system is a boiler with radiators, there will usually be only one room thermostat to control the whole house. But you can have different temperatures in individual rooms by installing thermostatic radiator valves (TRVs) on individual radiators. If you don't have TRVs, you should choose a temperature that is reasonable for the whole house. If you do have TRVs, you can choose a slightly higher setting to make sure that even the coldest room is comfortable, then prevent any overheating in other rooms by adjusting the TRVs.

Room thermostats need a free flow of air to sense the temperature, so they must not be covered by curtains or blocked by furniture. Nearby electric fires, televisions, wall or table lamps may prevent the thermostat from working properly.

The thermostat is compatible with OpenTherm OT+ 4.0 version. The OpenTherm protocol is an open standard communication protocol used in central heating systems for two-way communication between a central heating boiler and a room thermostat. Thanks to the communication protocol, the boiler power is modulated, which can significantly increase the energy efficiency of the heating system while maintaining the set temperature in the room. OpenTherm modulation, compared to standard communication (ON / OFF), occurs by setting the desired temperature of water from the boiler (boiler power), and not by its cyclical switching on and off.

PLEASE NOTE! Make sure your gas combi boiler is compatible with OT+ 4.0 communication protocol. The list of compatible boilers is on the next page.

Product advantages:

• Automatically detects OT+ 4.0 protocol and regulates hot water temperature.
• Possibility to choose Hysteresis or built-in TPI algorithm for all types of heating.
• Works with time schedules.
• Service mode protected by a PIN code.
• Maximum / minimum temperature limitation.
• Can temporarily change the temperature (overwriting until the next program change).

2.1 Example of boilers compatible with the OpenTherm OT+ 4.0 protocol

2.2 Montage

Refer to the diagrams for montage instructions. The package includes the thermostat, back housing, batteries, and mounting hardware.

2.3 Package content

• RT520 thermostat
• Back housing
• 2x AA batteries
• Short instruction
• Mounting screws

2.4 Proper thermostat location

The ideal position for thermostat mounting is about 1.5 meters above floor level, far from heating or cooling sources. The thermostat cannot be exposed to sunlight or extreme conditions like drafts. Due to fire and explosion risk, it is not allowed to use the thermostat in atmospheres of explosive gases and flammable liquids (e.g., coal dust). In case any of the listed dangers occur, additional protection measures like an anti-dust and explosive gases cover or prevention of their formation are required. Furthermore, the thermostat cannot be used in conditions of water vapor condensation and must not be exposed to water action.

2.5 Connection description

Symbols explanation:

• L, N - power supply 230V
• NO, COM, NC - voltage-free output
• A, B - OpenTherm Communication Wire
• SL - 230V AC voltage output - NSB function - fuse

I A - Boiler connection

Connect the boiler's ON/OFF terminals (according to the boiler's instructions) to the RT520's COM and NO terminals. The RT520 is powered by 2x AA batteries.

Diagram description: Shows RT520 with terminals COM, NO, NC, 3V, 2x AA. Boiler connection uses COM and NO.

I B - Pump / Valve connection

Connect the pump or valve control to the RT520's COM and NO terminals. This connection requires AC 230V power supply (L, N) and has a maximum rating of 3(1)A.

Diagram description: Shows RT520 with terminals COM, NO, NC, 3V, 2x AA. Pump/Valve connection uses COM and NO, with AC 230V L and N inputs.

I C - KL08NSB underfloor heating wiring center connection

The RT520 can be connected to a KL08NSB wiring center for underfloor heating systems. The COM and NO terminals of the RT520 are used to control zones via the wiring center.

Diagram description: Shows multiple RT520 units connected to a KL08NSB wiring center. Each RT520's COM and NO terminals connect to specific zone inputs on the KL08NSB. The KL08NSB also shows L, N, SL connections and zone outputs (1-8).

BOILER CONNECTION*: Boiler's contacts for ON/OFF thermostat (according to the boiler's instructions).

3. Before you start (first power up)

Make sure the receiver connections are made and the receiver is powered before inserting the batteries into the thermostat.

3.1 LCD icon description

[1] Text Bar

Displays text messages.

[2] Temperature Unit

Indicates the unit of temperature (°C or °F).

[3A] Day of the week (numeric)

Shows the day of the week as a number (1-7).

[3B] Day of the week (alphabetic)

Shows the day of the week as a letter (Mon-Sun).

[4] Clock

Displays the current time.

[5] AM / PM indicator

Indicates AM or PM for 12-hour time format.

[6] Cooling Mode On

Indicates that cooling mode is active. ❄️

[7] Holiday Mode On

Indicates that holiday mode is active. ✈️

[8] Manual Mode On

Indicates that manual mode is active. ✋

[9] Heating Mode On

Indicates that heating mode is active. ?

[10] Low battery status

Indicates that the batteries are low. ?

[11] Wireless connection with the receiver

Shows the status of the wireless connection. ?

[12] Service Mode On

Indicates that service mode is active. ⚙️

[13] Temperature measured / set

Displays the current room temperature or the set temperature.

[14] Program number

Shows the current program number.

[15] Settings

Indicates that the device is in settings mode.

[16] Program indicator

Shows the current program segment.

[17] Boost function

Indicates that the boost function is active. ?

3.2 Button description

[1] MENU / RETURN

Enter menu options. Press and hold for 3 seconds to return to the main screen or to deactivate Boost or Manual modes.

[2] SELECT

Confirm changes and enter menus.

[3] DOWN

Decrease the temperature and move through menus.

[4] UP

Increase the temperature and move through menus.

[5] BOOST

Activate Boost Mode. ?

[6] MANUAL

Press once to activate Manual Mode. Press and hold for 3 seconds to deactivate Manual Mode. ✋

PLEASE NOTE! The LCD screen can be activated by using any button.

3.3 First power up sequence and configuration

After inserting the batteries, the thermostat will power up.

1. Press the [SELECT] button.
2. Use the [UP] or [DOWN] buttons to choose your language and then press [SELECT].
3. Use the [UP] or [DOWN] buttons to choose the time format (12h or 24h).
4. Press [SELECT] to confirm.
5. Use the [UP] or [DOWN] buttons to set the hour and then press [SELECT].
6. Use the [UP] or [DOWN] buttons to set the minutes and then press [SELECT].
7. Use the [UP] or [DOWN] buttons to set the year and then press [SELECT].
8. Use the [UP] or [DOWN] buttons to set the month and then press [SELECT].
9. Use the [UP] or [DOWN] buttons to set the day and then press [SELECT].
10. Use the [UP] or [DOWN] buttons to select the week format (numeric or alphabetic).
11. Press [SELECT] to confirm.
12. Use the [UP] or [DOWN] buttons to enable or disable DST (Daylight Saving Time).
13. Press [SELECT] to confirm.
14. Press the [SELECT] button.
15. Use the [UP] or [DOWN] buttons to select your temperature accuracy (0.1°C or 0.5°C).
16. Press [SELECT] to confirm.

When OpenTherm is connected, the device software will automatically adjust to the OpenTherm settings.

17. Press the [SELECT] button.
18. TPI (Time Proportional & Integral) is a self-learning, time-proportional algorithm. TPI type of regulation ensures economical system operation through more accurate temperature maintenance during the controlling process and limits overload conditions. In addition to the exact and stable room temperature, the advantage of this system is the minimization of energy consumption and significant savings. RT520 offers 3 types of TPI control: 1. for radiator (6 CPH); 2. for underfloor heating (3 CPH); 3. for electric heating (9 CPH).
19. Use the [UP] or [DOWN] buttons to select the TPI type you want to use.
20. Press [SELECT] to confirm.
21. Span is the difference between the measured temperature and the set temperature.
22. Press the [SELECT] button.
23. Use the [UP] or [DOWN] buttons to select the Span value.
24. Press [SELECT] to confirm.
25. Press the [SELECT] button.
26. The optimization function is an energy-saving algorithm used for efficient control of the heating device, ensuring better thermal comfort at certain times of the day. When the OPTIMUM START function is active, the thermostat sends a heating signal to the heat source beforehand so that the preset temperature in the room is reached at the time specified in the schedule.
27. Press the [SELECT] button.
28. Use the [UP] or [DOWN] buttons to select ON or OFF for OPTIMUM START.
29. Press [SELECT] to confirm.
30. When the OPTIMUM STOP function is active, the thermostat, taking into account the inertia of the system, switches off the heat source earlier, keeping the temperature set in the schedule.
31. Use the [UP] or [DOWN] buttons to select ON or OFF for OPTIMUM STOP.
32. Press [SELECT] to confirm.

The thermostat will go to the main screen.

3.4 OpenTherm - Hot Water configuration

RT520 can be configured in an OpenTherm Hot Water system. To configure it, follow the steps below:

1. Press the [MENU/RETURN] button.
2. Use the [UP] or [DOWN] buttons to navigate to the Hot Water submenu and press [SELECT].
3. Use the [UP] or [DOWN] buttons to adjust the hot water temperature and then press [SELECT].

The thermostat will return to the main screen. Press any button.

The text bar indicates that hot water is in operation.

4. User settings

4.1 Manual mode

In manual mode, the thermostat maintains a constant temperature set by the user. To exit the mode, press and hold the [MANUAL] button for 3 seconds. A hand icon ✋ is displayed when manual mode is active.

1. Press the [MANUAL] button.
2. A hand icon ✋ will appear, which means that the thermostat is in manual mode.
3. To set the temperature, use the [UP] or [DOWN] buttons.
4. Confirm your choice using the [SELECT] button.

The thermostat will maintain the set temperature until a manual change or manual mode exit (press and hold [MANUAL] button for 3 seconds).

4.2 Schedule mode - programming schedule

In this mode, the user can set schedules for the thermostat (temperature setpoints for specific periods of time). Programmed schedules should use all time periods.

1. Press the [MENU/RETURN] button.
2. Press the [SELECT] button.
3. Use the [UP] or [DOWN] buttons to select the program type between: 5+2 (schedule for the working days and for the weekend), ALL (set one schedule for the entire week), or INDIVIDUAL (set a daily schedule).
4. Press [SELECT] to confirm.
5. Use the [UP] or [DOWN] buttons to set the hour and then press [SELECT].
6. Use the [UP] or [DOWN] buttons to set the minutes and then press [SELECT].
7. Use the [UP] or [DOWN] buttons to set the temperature and then press [SELECT].

Repeat the process for all time periods.

4.3 Switching between manual and schedule mode

In this option, the user can switch between manual and schedule mode by using the [MANUAL] button. To do that, please follow the steps below:

1. Press the [MANUAL] button. A hand icon ✋ will appear, which means that the thermostat is in manual mode.
2. Now press and hold the [MANUAL] button for 3 seconds.

The thermostat is in schedule mode again.

4.4 BOOST mode - hourly temperature override (+Hr)

The function is available in automatic and manual mode. Used to change the temperature to the desired value for a specified number of hours (up to 9 hours). After the elapsed time, the thermostat returns to the previous operating mode.

1. Press the [BOOST] button ? to set the hour for temporary override (e.g., 4 hours = 4 times button pressing). Confirm by pressing [SELECT].
2. Use the [UP] or [DOWN] buttons to set the temperature for BOOST mode. Confirm by pressing [SELECT].

The thermostat is working in BOOST mode for the set duration and will maintain the set temperature setpoint for that period.

How to stop BOOST mode:

1. Hold the [BOOST] button ? for 3 seconds, or press the [BOOST] button several times until "+0" appears and confirm by pressing [SELECT].

The thermostat will go back to the main screen and previous work mode.

4.5 Control and Heat/Cool settings

In this option, the user can set the control algorithm (TPI, SPAN or Optimize) and set the Heat / Cool mode. Please follow the steps below:

1. Press the [MENU/RETURN] button.
2. Use the [UP] or [DOWN] buttons to move between parameters and enter using the [SELECT] button.
3. Use the [UP] or [DOWN] buttons to move between parameters.
4. Confirm the HEAT / COOL option using the [SELECT] button.
5. Use the [UP] or [DOWN] buttons to move between parameters. Confirm your choice by pressing [SELECT].

4.6 Landlord settings

Landlord settings is a PIN code protected feature that allows the landlord to set a service reminder on the thermostat that will warn the tenant when the boiler is due its annual service.

1. Press the [MENU/RETURN] button.
2. Use the [UP] or [DOWN] buttons to navigate to the Landlord submenu and press [SELECT].
3. Use the [UP] or [DOWN] buttons to enter the PIN code number. Press [SELECT] to confirm every digit. Note: The first PIN code entry is also the setting of a NEW PIN CODE which must be entered each time to enter the LANDLORD (Admin) menu.
4. Please remember to write down your PIN code so that you can use the Landlord menu later without any hassle from losing it.
5. Press [SELECT].
6. Use the [UP] or [DOWN] buttons and press [SELECT] to set the service reminder ON.
7. Use the [UP] or [DOWN] buttons to select the due date and then press [SELECT].
8. Use the [UP] or [DOWN] buttons to select the warning period and then press [SELECT].
9. Use the [UP] or [DOWN] buttons to select the lock temperature and then press [SELECT].
10. Use the [UP] or [DOWN] buttons to enter the phone number. Press [SELECT] to confirm every digit.
11. To confirm and exit this option, use the [SELECT] button. Then use the [UP] or [DOWN] buttons again to move to the next LANDLORD options (look at the next steps).
12. Use the [UP] or [DOWN] buttons to move to the next option.
13. Press [SELECT].
14. Use the [UP] or [DOWN] buttons to select the correct MAX temperature setpoint value. Confirm by pressing [SELECT].
15. Now, use the [UP] or [DOWN] buttons to select the correct MIN temperature setpoint value. Confirm by pressing [SELECT].

The thermostat will go back to the SERVICE option. To go back to the main screen, wait 10 seconds or press the [MENU/RETURN] button as long as the main screen is displayed.

4.7 Time/Date

To set time/date, follow steps below:

1. Press the [MENU/RETURN] button.
2. Use the [UP] or [DOWN] buttons to move between parameters.
3. Press [SELECT] to enter Time/Date settings.
4. Use the [UP] or [DOWN] buttons to choose the time format. Press [SELECT] to confirm.
5. Use the [UP] or [DOWN] buttons to set the hour and then press [SELECT].
6. Use the [UP] or [DOWN] buttons to set the minutes and then press [SELECT].
7. Use the [UP] or [DOWN] buttons to set the year and then press [SELECT].
8. Use the [UP] or [DOWN] buttons to set the month and then press [SELECT].
9. Use the [UP] or [DOWN] buttons to set the day and then press [SELECT].
10. Use the [UP] or [DOWN] buttons to select the week format. Press [SELECT] to confirm.
11. Use the [UP] or [DOWN] buttons to enable or disable DST (Daylight Saving Time). Press [SELECT] to confirm.

The thermostat will go to the main screen with all settings saved.

4.8 Holiday mode

Holiday mode is a special program temperature setpoint which the thermostat will maintain for specified days. How to set HOLIDAY MODE:

1. Press the [MENU/RETURN] button.
2. Use the [UP] or [DOWN] buttons to move between parameters.
3. Press [SELECT] to enter holiday mode settings.
4. Use the [UP] or [DOWN] buttons to set the year and then press [SELECT].
5. Use the [UP] or [DOWN] buttons to set the month and then press [SELECT].
6. Use the [UP] or [DOWN] buttons to set the day and then press [SELECT].
7. Now do the same steps to set the holiday mode's final day. Use the [UP] or [DOWN] buttons to set the hour and then press [SELECT].
8. Use the [UP] or [DOWN] buttons to set the minutes and then press [SELECT].
9. Use the [UP] or [DOWN] buttons to set the temperature which should be maintained during holiday mode and then press [SELECT].

According to the set period of time, the plane icon ✈️ will appear on the main screen and the thermostat is working in holiday mode.

To abort holiday mode, just press any button and then confirm HOLIDAY STOP by pressing [SELECT]. The plane icon will disappear and the thermostat will go back to the previous work mode.

4.9 Language

To choose the language, follow steps below:

1. Press the [MENU/RETURN] button.
2. Use the [UP] or [DOWN] buttons to move between parameters.
3. Press [SELECT] to enter language settings.
4. Use the [UP] or [DOWN] buttons to choose your language.
5. Press [SELECT] to confirm.

The thermostat will go to the main screen with the changes saved.

5. Factory Reset

To RESET the RT520 thermostat to its factory default settings, please follow the steps below:

1. To reset the thermostat, press and hold together the [UP], [DOWN], and [SELECT] buttons for 5 seconds.

The thermostat has been reset. PLEASE NOTE: User settings will not be deleted.

6. Error codes

The thermostat will display errors only when it's connected to the boiler via OpenTherm terminals (A / B). Please refer to the boiler manual. Each boiler can have different error codes.

7. Battery change

Turn the thermostat over so that the back is in front of you. Now look at the picture. INSERT THE BATTERIES, PAYING ATTENTION TO THEIR POLARITY!

8. Cleaning and Maintenance

The RT520 thermostat requires no special maintenance. Periodically, the outer casing can be wiped clean using a dry cloth (please DO NOT use solvents, polishes, detergents, or abrasive cleaners, as these can damage the thermostat). There are no user-serviceable parts within the unit; any servicing or repairs could only be carried out by Salus Controls or their appointed agents.

9. Technical Informations

Power supply

2 x AA batteries

Rating max

3 (1) A

Output signal

OpenTherm (A / B) or voltage-free relay (NC / COM / NO)

Temperature range

5 - 33.5°C

Display temperature accuracy

0.1°C or 0.5°C

Control algorithm

TPI or Hysteresis: ±0.25°C or ±0.5°C

Communication

Wired

Dimension [mm]

95 x 118 x 26

10. Warranty

SALUS CONTROLS warrants this product to be free from any defects in material or workmanship and to perform as specified for a period of five years from the date of installation. SALUS CONTROLS reserves the sole responsibility for breach of this warranty by repairing or replacing the defective product. This product includes software that matches the distributor's identification at the time of sale. The manufacturer / distributor provides a guarantee covering all functions and specifics of the product in accordance with this marking. The distributor's warranty does not cover the correct operation of the functions and features available as a result of a product software update. The full warranty conditions are available at www.salus-controls.eu.

Importer and Producer Information

IMPORTER: QL CONTROLS Sp. z o.o. Sp. k. ul. Rolna 4, 43-262 Kobielice

PRODUCER: Salus Limited 6/F, Building 20E, Phase 3, Hong Kong Science Park, 20 Science Park East Avenue, Shatin, New Territories, Hong Kong

www.salus-controls.eu

SALUS Controls is a member of the Computime Group.

Maintaining a policy of continuous product development, SALUS Controls plc reserves the right to change specifications, design, and materials of products listed in this brochure without prior notice.

Ver. 3 Issued: 19 III 2021 Soft version: 2.2