The lmmergas VICTRIX and HERCULES condensing boilers can supply a low-temperature heating system directly once the jumper on the boiler's electronic board has been changed. On the lmmergas VICTRIX, for example, the flow temperature to the heating system can be set to a control range of 25 °C to 50 °C. Under these conditions it is advisable to wire a safety thermostat with a limit temperature of 60 °C in series with the boiler's power supply (for this specific case). On this model, the thermostat must be fitted on the flow pipe to the heating system at least 2 metres from the boiler.
You will find the full range in the underfloor heating category – system insulation boards, pipe, manifolds, controls and electric heating mats.
Connecting a 2-zone or 3-zone DIM to condensing boilers
Once the boiler has been set for direct low-temperature operation, a 2-zone or 3-zone DIM unit makes it possible to control low-temperature circuits (such as underfloor heating) divided into zones, as the following example illustrates.
If a CAR or Super CAR is used to control a zone, it is wired directly to the boiler. The CAR (or Super CAR) will control the one zone that is defined as the main zone on the hydraulic manifold. The CAR (or Super CAR) must be set to On-Off operating mode (see the instructions in the user manual for the device concerned).
When a CAR (or Super CAR) is used, the room thermostat terminals for the main zone on the hydraulic manifold must be left unconnected.
The electrical connection between the boiler and the DIM must not be longer than 15 metres.
2-zone and 3-zone kits for HERCULES models (by Immergas)
The HERCULES boiler can serve a low-temperature system directly: this is achieved by setting the boiler's electronic board to a flow temperature range of 25-45 °C to the heating system.
Connecting the 2-zone or 3-zone control kits allows the boiler to serve systems divided into low-temperature zones only. A boiler working directly with a low-temperature circuit must be fitted with a safety device which, in the event of a fault, ensures that the temperature does not exceed the 55 °C limit, above which problems could arise in the low-temperature circuit.
The low-temperature safety thermostat is wired in series with the system circulation pump so that the thermostat switches the pump off when the temperature limit (55 °C) is exceeded.