Comparison Salus RT 310i vs Salus 091FLRF

The type of equipment for which the regulator is suitable.

Modern thermostats and automation systems can be used for:

- For different types of boilers — gas, electric, solid fuel.
- For heaters and underfloor heating - for both at the same time: the control features in both cases are very similar, which makes it easy to combine them in one device.
- For pumps — namely for circulation pumps of heating systems.
— For heat pumps. A heat pump provides heat transfer from the environment to the room, providing heating. (Air conditioners work on a similar principle, but their main task is cooling).
— For fancoils. A fancoil is a device that cools or heats air by passing it through a system of pipes with a coolant circulating through them. And for the necessary heating or cooling of the coolant, another component of the system is responsible - a chiller, usually installed outdoors. A feature of such climate systems is that most of them can be used not only for heating in the cold season but also for cooling in the hot season.
— For outdoor system. Regulators for various climatic equipment installed outdoors. These can be, for example, anti-icing systems, devices f...or heating pipelines, chillers for chiller-fan coil systems, etc.

In many models, several options are combined at once; for example, most devices for electric boilers are quite compatible with gas boilers.

In any case, it is the first criterion that one should pay attention to when choosing.

The way to install the thermostat.

— Into mounting box. Installation in a standard junction box. Simply put, the regulator is mounted into the wall in the manner of a conventional switch or socket (most often even the mounting dimensions are the same, although there are exceptions). For installation, most likely, you will have to work with a rotary hammer, but the device will be securely fixed and at the same time will take up a minimum of space.

— On wall. These thermostats usually have a flat shape with a small thickness. Wall mounting is easier than embedding, but somewhat less reliable — in case of an unfortunate set of circumstances, the device can be hit and seriously damaged.

— To boiler. Installing a thermostat directly on the boiler. This option is traditional for devices used in solid fuel boilers (see "Type") that control combustion through a chain connected to an air damper, but it can also be found in other types of regulators — for example, designed for gas boilers. In the first case, this method of installation is due to the design features of the device (see "Chain length"). In the second case, installation on the boiler simplifies the design and installation, but at the same time makes the regulator not very convenient: on the one hand, the design does not have a remote unit, the connection of which is associated with certa...in troubles, on the other hand, you will have to approach each time to adjust the thermostat. to the boiler, which is not always convenient.

— DIN rail. Mounting on a special metal rail, which can also be used for electrical grounding. Such rails are commonly used in distribution boards. Most often, this installation method is used in industrial equipment, although it can also be useful for residential premises. Note that there are several types and sizes of DIN rails. Therefore, before buying a regulator with such an installation, it is highly desirable to clarify its compatibility with the seat.

— Portable. Devices that do not require permanent installation in the same place. By definition, they use a wireless connection (see above). Most often, portable thermostats are equipped with stands for installation on a table or other flat surfaces and are designed more for desktop use than for the role of a portable remote control. Nevertheless, the design makes it easy to move such a device from place to place, which can be useful, for example, in a large house, where you have to be in different places at different times and it would be inconvenient to run to the wall or built-in thermostat every time. Among the disadvantages of portable thermostats, one can mention the rather high cost and the need to use a battery (respectively, a limited operating time).

— In socket. Thermostats plugged into a regular household outlet. Usually, such devices have their own socket on the case and play the role of an adapter switch through which an electric heater (or other device) is connected to the network. With this connection, the thermostat controls the power coming from the outlet: turns it off when the required temperature is reached and turns it on when necessary. Such devices are extremely easy to install. Moreover, they are easily rearranged from outlet to outlet. On the other hand, the very location of the thermostat is not very convenient — sockets are often located in hard-to-reach and not the best places for a temperature sensor.

The maximum load in terms of current power that the thermostat can withstand. In other words, the maximum electrical power that it can pass through itself without failures and damage.

The choice for this parameter directly depends on the power consumed by the boiler or heater connected through the thermostat; load limitation is of particular importance when working with electric boilers, the energy consumption of which is measured in kilowatts. When connected directly, the power of the heater should not exceed the maximum load of the thermostat, otherwise the latter will simply fail. However, when using additional protective devices (contactors), many models allow connection to a more powerful load than originally allowed.

It is the range in which the air temperature can be set on the regulator. The choice for this indicator depends on the expected conditions in the room. So, in a residential building, the lower temperature limit at the level of 5–10 °C is quite sufficient; the upper limit is within 30–40 °C (regardless of whether we are talking about air or floor temperature). But in control devices designed for industrial use, this range will be much wider — from sub-zero temperatures to the upper limit of 100 – 125 °C.

Automatic temperature control hysteresis provided by the device.

Hysteresis can be described as the difference between the on and off temperatures of a system controlled by a thermostat. Usually, the permissible deviations of the actual temperature from the nominal one in one direction or another are half the hysteresis. So, at a set temperature of 22 °C and a hysteresis of 0.5 °C, the controller will turn on the heating as soon as the room temperature drops to 21.75 °C, and turn it off when it rises to 22.25 °C. Accordingly, the lower this indicator, the more carefully the temperature is maintained and the fewer fluctuations. On the other hand, small hysteresis values require accurate and expensive thermal sensors, increase fuel/energy consumption and wear of the entire system, and create an increased risk of false alarms (for example, from a cool draft on the thermal sensor). In addition, relatively small temperature fluctuations are practically imperceptible in terms of human comfort. Therefore, many modern thermostats have a hysteresis of 1 °C — this, usually, is quite enough for domestic use.

Also note that this parameter can be both fixed and adjustable. The first option is simpler and cheaper, and the second provides additional options for setting the thermostat to the specifics of the situation.

The presence of an air temperature sensor in the design or delivery set of the controller — such a sensor can be either built into the device or external.

Air temperature is one of the key parameters that determine the climate in the room and the comfort of staying in it. Accordingly, the air temperature sensor allows the regulator to evaluate the general conditions in the room and control the heating operation, taking into account how the microclimate corresponds to the desired one. However, note that such sensors are not always applicable. For example, in kitchens and bathrooms, they may not work correctly (when hot water, a gas stove or a water heater is turned on, etc.), so in such conditions it is better to use floor temperature sensors (see below).

The type of timer provided in the design of the thermostat. In this case, a timer means a scheduler that allows you to programme different operating modes for different periods (for example, lower the temperature at night and increase it by the time you get up). Such schedulers are divided into types depending on the time covered.

— Daily. The timer allowing to set the programme within 24 h; then the programme will be repeated every day. This variety is the simplest and, as a result, inexpensive. On the other hand, for most users, the daily routine on weekdays and weekends are noticeably different, and, most likely, the timer will have to be reprogrammed at least twice every week — before the weekend and at the end of the weekend.

— Weekly. A timer that allows you to set a work programme for certain days of the week. The simplest varieties of such schedulers work according to the “5 + 2” scheme: one programme is set for 5 working days, the other for 2 days off. However, there are more advanced options — up to the ability to programme each day of the week separately. Anyway, weekly timers are more convenient and require less reprogramming than daily timers but they are much more expensive.

The largest number of individual cycles that the thermostat timer can set in one day.

The cycle is the period during which the thermostat operates on one set of settings. For example, if there are 2 cycles, you can provide turning off the heating while you are at work and turn it on shortly before returning home. However, most thermostats provide a noticeably larger number of cycles — up to 24.

Note that in weekly timers (see "Timer type") this parameter may differ depending on the day of the week. For example, weekdays usually have more extensive settings than weekends.

The shortest duration a programmable thermostat cycle can have (see "Programmable cycles per day").

The lower this parameter (with the same number of cycles per day) — the wider the possibilities for programming the operation of the thermostat, in particular, for its specific setting (for example, you can provide a short period of preliminary "intensive heating" after working at low temperatures). On the other hand, due to a certain inertia in the operation of heating systems, it makes no sense to make an interval shorter than 10 minutes — the thermostat simply does not have time to work out the specified settings in less time. And in the most "long" models, this parameter is about 30 minutes.