Which RTL Control Box Is Right for My Project?
Two control boxes are available for the heating kits to control the temperature and for connection to the existing heating system. In both cases, the heating water temperature is controlled via a return temperature limiter [RTL]. The table provides a direct comparison of the respective range of functions.
 |
 |
|
| Multibox 4k-RTL | Kompabox RTL | |
| Connection to conventional heating systems with 70°C flow temperature | check_circle | check_circle |
| Connection to panel heating systems with max. 50°C flow temperature | check_circle | |
| Return temperature limiter | check_circle | check_circle |
| Connection for bathroom radiator | check_circle | |
| Flow shut-off | check_circle | check_circle |
| Bleed valve - removal of air from the heating system | check_circle | |
| Thermostatic head with V-exact II for carrying out hydronic balancing | check_circle | |
| Smarthome ready* | check_circle | |
| Installation dimensions in mm (H×W×D) | 190×240×60 | 150×230×60 |
| Product pages | Details | Details |
* For integration into Smarthome systems, the thermostat head of the Multibox 4K-RTL can be exchanged and replaced with a wireless radiator thermostat. The Smarthome thermostat head must fit a 30 × 1.5 mm connection thread or have an appropriate adapter. Integration into a Smarthome system offers additional control convenience, especially when operating several heating sets.
question_exchange
The thermostatic head of the Multibox 4K-RTL valve can be replaced by a smarthome servo drive. Depending on the smart home system used, there are various brands to choose from. The smart home-compatible thermostat must have an M30x1.5 connection thread and come with the appropriate adapters for the IMI thermostat head K, which is installed as standard in the Multibox.
The control of the heating temperature via the RTL principle (=return temperature limiter) is an established heating control technology. It is particularly suitable if the new radiant heating is to be integrated into an existing heating system with higher flow temperatures. The RTL valve permanently measures the heating water temperature in the heating circuit. If this is too high for a radiant heating system (the limit is about 45°C), the valve interrupts the flow through the heating circuit and no further hot water flows into the heating circuit. Thus, the water in the heating circuit then cools down again. If the temperature falls below the maximum temperature of the radiant heating, the RTL valve opens again. A detailed technical explanation of how it works can be found directly on the product pages for our RTL boxes.
An RTL valve is required for connection to heating systems that feed water into the circuit at a flow temperature of up to 65°C. RTL stands for return temperature limiter.
The Multibox 4K-RTL limits the return temperature and has a flow shut-off including a vent valve and a regulating spindle with which hydraulic balancing can be carried out.
It is controlled without additional energy and can be individually adjusted using the thermostatic head supplied. This functions as a continuous proportional controller. The change in the room air temperature (controlled variable) is proportional to the change in the valve stroke (actuating variable). If the room air temperature rises, the temperature in the temperature sensor expands and acts on the corrugated pipe. This throttles or increases the water supply in the underfloor heating circuit via the valve spindle.
Even if the heat generator is to be replaced at a later date with a modern heat source with low heating temperatures, such as a heat pump, the Multibox 4k-RTL can still be used. Because the flow temperature will then be moderately below 45°C, the Multibox will not have to regulate and you can continue to use the actuator. Our alternative RTL box, the Kompabox RTL, is not suitable for this.