Resetting and restoring factory settings of a programmable thermostat

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Resetting and restoring factory settings of a programmable thermostat: a complete guide

Resetting a programmable thermostat is one of those things most people don't need for years – and then suddenly need it urgently, at midnight, when the boiler isn't responding and the room temperature is 16 degrees. Or it's needed by an installer taking over an old device from a previous tenant, where the thermostat is programmed with unknown times and temperatures. Or it's you, after a year of experimenting with settings, when the device has become such a mess that it's easier to start from scratch than to try to make sense of it.

This article covers resetting programmable thermostats from all angles: why to reset, what types of reset exist, what happens to data with each type, how to proceed with specific models, what to do after resetting, and how to avoid the most common mistakes. If you came here with a specific problem, use the headings for navigation. If you want to really understand the topic, it's worth reading the whole article.

Why reset a thermostat at all? Real-life situations from practice

Before we dive into the technicalities, it's worth understanding when a reset makes sense and when it doesn't. From practice, we can identify several typical scenarios where restoring factory settings is the right solution.

The thermostat has stopped responding or is behaving oddly

The most common case. The display has frozen, the buttons aren't responding, the device isn't communicating with the boiler, even though the wiring is correct. The cause may be a software error – a kind of "crash" in the firmware. It's similar to when your phone freezes: the physical components are fine, but the software has locked up. A reset in such a case serves as a system restart and often solves the problem without the need to replace the device.

Unknown password or locked menu

Many thermostats allow settings to be locked with a PIN code or customer code to prevent changes, for example, by children. The problem arises when the code is forgotten, or when you take over the device from another person – for example, when buying a property, renting an apartment, or changing tenants. Without knowing the code, you can't access advanced settings, and a reset is the only solution in such a case.

Incorrectly programmed times and temperatures that can't be found

This happens to people who experiment with a programmable thermostat. They set up some program, then change it, change it again, overlap time zones, set the same temperature in all zones, and in the end, they can't tell what's set where. In such a case, it's faster and safer to restore factory settings and start from scratch with a clean slate.

Preparing the device for sale or handover

If you're replacing a thermostat and passing on the old device, courtesy (and sometimes practicality) requires you to erase all your settings. The new owner then receives the device in a condition as if it were out of the box and can program it according to their own needs.

After a power outage, when settings are lost

Older or cheaper thermostats without a backup battery or with a dead battery lose their settings, including time and program, during a power outage. After power is restored, they display nonsensical times or start a default program that doesn't match your needs. Although technically this isn't a reset in the strict sense, the situation is the same: you're starting from scratch and it's good to know how to proceed.

Types of resets: not every reset is the same

The term "reset" in the world of thermostats refers to several different operations with different effects. It's important to distinguish between them to avoid accidentally erasing more than you wanted – or conversely, to avoid performing only a partial reset when a full reset is needed.

Soft reset (soft reset / restart)

This is the simplest intervention – the device is restarted, and all stored settings remain untouched. It's equivalent to turning it off and on again. It is usually performed by removing the batteries for 30–60 seconds, or by disconnecting from power. For some models, there is a dedicated RESET button on the side or in the battery compartment that performs exactly this type of restart.

Program reset (software reset)

This type of reset will erase only the user-defined weekly schedule and return the temperatures to the factory default settings (usually 20 °C during the day, 16 °C at night). Other settings – sensor calibration, hysteresis, safety functions, password – remain unchanged. It is a suitable solution when you want to start programming from scratch, but your other settings are still acceptable.

Factory reset (full reset)

The most thorough intervention. It returns the device to the state it was in when it left the factory. The following are erased: all programs, time and date settings, thermometer calibration, hysteresis, safety limits, password/PIN, communication protocol settings (for Wi-Fi thermostats, also network settings). After a factory reset, the device must be reconfigured from scratch – starting with the time and day of the week.

What is lost and what remains after reset: detailed overview

Before any reset, you should know what will be erased and what will remain. It depends both on the type of reset and on the specific thermostat model. The following table shows typical behavior after a factory reset:

Parameter	Soft reset	Program reset	Factory reset
Weekly program	✓ remains	✗ erased	✗ erased
Time/date settings	✓ remains	✓ remains	✗ erased
Temperature sensor calibration	✓ remains	✓ remains	✗ reset to zero
Hysteresis	✓ remains	✓ remains	✗ factory value
Lock / PIN	✓ remains	✓ remains	✗ erased
Wi-Fi / RF pairing	✓ remains	✓ remains	✗ erased

Note: The above applies to most common thermostats, but each manufacturer may have slightly different implementations. Always read the manual for your specific model before pressing the reset button.

How to perform a reset: methods and procedures

Manufacturers implement reset functions in various ways. Let's look at the most common ones, with specific examples from thermostats we encounter in practice.

Method 1: Dedicated reset button

Some thermostats, especially cheaper and simpler models, have a physical button labeled "RESET". It is usually located in the battery compartment or on the side edge of the device. It is often recessed to prevent accidental pressing – a pin or the tip of a paper clip is usually needed to activate it. Pressing and holding it for 3–10 seconds initiates the reset process. Some models require the device to be on, others to be off. This can only be determined from the manual.

Method 2: Button combination on the display

The most popular method used by most modern mid-range thermostats. The reset combination varies by manufacturer and model, but in practice, you will most commonly encounter these variants:

Simultaneously holding the "up" and "down" buttons (▲ + ▼) for 5–10 seconds
Simultaneously holding "Menu" and "OK" or "SET" for 5 seconds
A combination of three buttons – for example, "Menu" + ▲ + ▼ simultaneously
Long press of the "Menu" button alone (8–12 seconds) to enter the service menu

The reset combination is always listed in the user manual, usually in the "Troubleshooting" or "Technical Settings" section. If you have lost the manual, they can be found on the manufacturers' websites or on seller pages – most serious e-shops provide product manuals.

Method 3: Reset via Service Menu

With more advanced programmable thermostats, a factory reset is hidden deep within the service or installer menu, which you can access by entering a service code. This approach is intentional – it protects the settings from being accidentally erased by regular users. The service code is usually provided by the manufacturer in the installation documentation (not in the standard user manual). If you cannot find it, contact the seller or the manufacturer's technical support.

Method 4: Removing Batteries / Disconnecting Power

This is more of a soft reset than a factory reset, but in combination with another procedure, it can be part of the reset process. Removing the batteries for 30–60 seconds (in battery-powered models) or disconnecting the electrical power for the same period allows the capacitors in the internal circuits to discharge and the device to restart into a clean state – however, the settings stored in the non-volatile EEPROM memory will remain (data is retained even without power).

Specific Models and Their Reset Procedures

Now we will look at specific devices that we encounter in practice and are available in the category of programmable thermostats.

SALUS 091FL

SALUS 091FL is a wired programmable thermostat with a weekly 5+2 or 7-day schedule. The reset on this model is performed by simultaneously pressing and holding the "SET" and "Manual" buttons (marked with a hand symbol) for 5 seconds until the display shows confirmation. Alternatively, you can enter the installer menu using a code – this can be found in the technical documentation. After a factory reset, it is necessary to re-set the time, day of the week, and the entire schedule. The thermometer calibration will also be reset – if you previously adjusted it, you will need to recalibrate it again. For more information on why the thermostat shows a different temperature than the thermometer, read the article Calibration and Accuracy of Temperature Measurement: Why the Thermostat Shows Differently than the Thermometer in our Knowledge Center.

Euroster Q7

Euroster Q7 is a Polish model with intuitive control and colorful icons. The reset is performed by entering the service menu – the combination code is listed in the installation manual. After entering the code, you will find an item labeled "Factory reset" or its equivalent in the menu. The Euroster Q7 also offers a partial reset, which only clears the schedule and retains other settings – this option is more practical when programming a new household, provided that other parameters (hysteresis, safety temperatures) are correctly set. After the reset, the time and schedule are set to factory defaults, including the default schedule with fixed temperatures.

Saswell SAS 908 7 and Saswell T19 7 B

Saswell SAS 908 7 and Saswell T19 7 B are devices from the Chinese manufacturer Saswell, well established in European markets. On these models, the factory reset is usually triggered by holding the ▲ + ▼ buttons for 8–10 seconds, during which the display shows a flashing message or a reset symbol. Confirm by pressing "OK". Important: on models with an external floor sensor (NTC sensor wiring), after a factory reset, the input type will be set to the internal sensor – if you use a floor sensor, you must select the correct input type again in the installer menu, otherwise the device will measure incorrect temperatures and behave unpredictably.

Saswell 908 7 RF (Wireless Model)

Saswell 908 7 RF is a wireless version with a separate receiver (the receiver is mounted near the boiler, and the thermostat is portable). When performing a factory reset on this model, it is crucial to reset both components – the thermostat and the receiver. If you reset only the thermostat, the pairing with the receiver will be lost and the system will stop working. Procedure: first reset the receiver (it usually has a dedicated RESET button on the body), then reset the thermostat. After that, you must re-pair both components – the pairing procedure is described in the manual and usually involves putting the receiver into pairing mode and initiating the pairing process on the thermostat. For more information on the differences between wired and wireless thermostats, see the article Wired or Wireless Programmable Thermostat: Which One Suits Your System.

What to Do Before Reset: Backup Settings

A factory reset is irreversible. This means that once you start it, there is no "back" button. Therefore, it is reasonable to document the current state of the device before the reset. If this seems time-consuming, remember it next time when you will have to search for the correct hysteresis values for your specific boiler again.

What to note before resetting:

Weekly schedule: all time zones for each day of the week, target temperatures in each zone. The best way is to take a photo of the display for each setting or record it in a table.
Thermometer calibration: if you have calibrated the thermostat, record the offset value (usually expressed in ±°C). After the reset, you will have to repeat the calibration.
Hysteresis: the temperature difference at which the boiler turns on and off. The factory setting is usually 0.5 °C or 1 °C, but if you have changed it, record the current value.
Protection limits: minimum and maximum allowed temperature, frost protection.
Sensor type: built-in air sensor, floor NTC sensor, or combined. This setting is critical for proper operation.
Service code (if changed): if you have changed the factory service code, record the new one.

Procedure after factory reset: what to set and in what order

After a successful reset, you will have a device in a brand new state. Now follows the setup in a logical order, reflecting the dependencies of individual parameters.

Step 1: Setting the clock and day of the week

The first and absolutely necessary thing. A programmable thermostat without a properly set time is useless – it will not know when to activate which time zone. On most thermostats, the clock is set by pressing the "CLK" button or by long-pressing "SET" when the current time is displayed. Set the hours, minutes, and day of the week (note: most European thermostats count Monday as the first day, while some American models start with Sunday – check the manual).

Step 2: Setting the sensor type

This is a critical setting that must be done before any other. If your thermostat supports an external floor sensor (NTC probe), you must select the correct input type in the technician menu. The options are usually three:

IN: only internal air sensor
FL: only external floor sensor (thermostat regulates based on floor temperature)
AL: combined – regulates based on air, but the floor sensor serves as a safety limit

After a factory reset, the type is always set to IN. If you use a floor sensor and do not set this, the thermostat will respond to the current air temperature in the room and you will wonder why the floor is cold, even though the thermostat "does not indicate a need for heating".

Step 3: Hysteresis and protection limits

Hysteresis determines by how many degrees the temperature must drop below the set value for the boiler to turn on, and by how many degrees it must rise above the set value for the boiler to turn off. A factory setting of 0.5 °C is suitable for most situations. For condensing boilers with modulation, you can increase it to 1 °C to avoid short cycling. For older boilers without modulation and with high power (30+ kW), a hysteresis of 1–1.5 °C may be appropriate. Set the protection limits (minimum temperature, maximum temperature) according to the requirements of your heating system.

Step 4: Calibration of the temperature sensor

If you calibrated the thermometer before the reset and have recorded the offset value, enter it again. If not, place a reference thermometer in the same location as the thermostat (on the wall, at a height of 1.2–1.5 m, away from direct sunlight and drafts) and wait 30 minutes. Compare the values and if the difference is more than 1 °C, set the correction. The topic of calibration is discussed in more detail in the article "Calibration and Accuracy of Temperature Measurement" in our Knowledge Center.

Step 5: Programming the weekly schedule

The last step and at the same time the most important one in terms of energy saving. Here you set the times when the room should be heated to a comfortable temperature and when a setback temperature is sufficient. A detailed guide on programming time zones can be found in the article Weekly thermostat program: how to correctly set time zones and temperatures. A typical recommended setting for a working household:

6:00–8:00 – comfortable temperature 21 °C (morning wake-up)
8:00–16:00 – setback temperature 16–17 °C (empty household)
16:00–22:00 – comfortable temperature 21 °C (coming home)
22:00–6:00 – night setback temperature 17–18 °C (sleeping)

Problems you may encounter: errors during reset and their solutions

Thermostat cannot be put into reset mode

The most common cause: incorrect button combination or not holding the buttons long enough. Most thermostats require holding for 5–10 seconds – count aloud, because 5 seconds feels longer than expected. Another cause: the thermostat is locked. If you set a PIN before locking, the reset will not work in the locked state. Try entering the factory PIN (usually 0000, 1234 or a number from the manual) and unlock the thermostat.

Reset was performed, but the thermostat still behaves the same

If old settings remain after the reset, it may mean that only a soft reset was performed instead of a factory reset. Check whether the correct type of reset was done. Another possibility: the backup battery (CR2032 or similar, which some models have to preserve the time during power outages) retains the settings even when the main batteries are changed. In this case, you need to replace the backup battery as well and repeat the reset.

After the reset, the thermostat does not control the boiler

This is a problem that comes from an incorrectly set output relay or protocol. After a factory reset, the relay is set to normally open contact (NO). If your boiler requires normally closed contact (NC), you must change this in the installation menu. Also check whether the correct temperature for activation is set – if the target temperature is lower than the current one, the boiler will not turn on and the thermostat will behave correctly, but you will mistakenly think it is not working. Compatibility of the thermostat with the boiler is discussed in detail in the article Compatibility of programmable thermostats with boilers and heating systems.

Wireless thermostat does not communicate with the receiver after reset

As mentioned in the case of Saswell 908 7 RF: resetting the thermostat will cancel the pairing. You must pair both components again. Follow the receiver's manual – usually it involves putting the receiver into pairing mode (LED blinks rapidly) and then starting the pairing from the thermostat's menu. If pairing still does not work after several attempts, check the mutual distance (it should not be through thick reinforced concrete walls or very far) and try pairing with the thermostat placed directly next to the receiver.

Situations when reset WILL NOT HELP – and what to do instead

Not every problem can be solved with a factory reset. It is good to know when a reset is ineffective and the problem lies elsewhere:

Physically damaged temperature sensor: if the NTC sensor (internal or external) shows a short circuit or broken circuit, reset will not help – the sensor must be replaced or the wiring checked.
Relay failure: if the relay inside the thermostat physically does not switch, reset will not fix it. The relay can be tested with a multimeter in continuity mode when the heating is turned on.
Compatibility issue with the boiler: some condensing boilers with modulation require a special protocol (OpenTherm). If you have such a boiler, a regular on/off thermostat will never understand it, regardless of the reset.
Dead or faulty battery: if the thermostat uses batteries, a dead battery can cause strange behavior – frozen display, incorrect temperature readings. Reset will not help here; you need to replace the batteries with new alkaline ones.
Faulty firmware: extremely rare, but possible. If the thermostat repeatedly freezes despite resets and battery changes, it may be a firmware issue that is resolved by contacting the manufacturer for a replacement.

If the problem persists after a factory reset and you are sure the settings are correct, see the article Common faults of programmable thermostats and how to eliminate them, where each fault is systematically analyzed and diagnosed.

Preventive measures: how to avoid situations where reset is necessary

From a long-term perspective, it is better to prevent situations that lead to a necessary reset. A few practical tips from practice:

Document the settings right after installation. When the installer removes the thermostat and sets all parameters, ask them to record all values or take a photo. It will save you hours of searching when setting it up again. A detailed installation procedure can be found in the article Installation of a programmable thermostat: step-by-step installation guide.

Regularly replace the batteries. Batteries should be replaced once a year, ideally at the beginning of the heating season. Do not wait until the display starts flashing a warning – a dead battery can cause loss of settings and unpredictable behavior.

Do not experiment with the installation menu without documentation. If you enter the service menu and change a setting, always note the old setting for reference. This is especially important for hysteresis, sensor type, and safety limits.

Use the lock function carefully. The keyboard lock function is useful if you have children at home or do not want tenants to change the settings. But write down the PIN in a safe place – a forgotten PIN without factory documentation leads directly to a factory reset.

Most frequently asked questions (FAQ)

I lost the thermostat manual. Where can I find the reset procedure?

First option: the manufacturer's website. Every serious manufacturer (SALUS, Saswell, Euroster) publishes manuals for free download. Search by the exact model designation. Second option: the seller from whom you bought the thermostat. Reputable online shops provide or publish manuals directly with the product. Third option: communities and forums – for popular models you can find the reset procedure in

Do you have a question about this topic?

Not sure or dealing with a specific situation in your household? Write to us – we are happy to help.