Installations with high-volume radiators
+ underfloor heating with thermostatic mixing valves
Installation with mixed zones:
- radiators served by zone pumps (high flow rate)
- underfloor heating with thermostatic mixing valves
Connection to a boiler that is ready for a zone control unit
BOILER: in this case the boiler is configured for connection of a zone control unit. The boiler may heat domestic hot water either instantaneously or via a cylinder, and may have a sealed or an open combustion chamber.
The boiler does not have to be fitted with a by-pass (lmmergas fits this device as standard to the great majority of its boiler models).
ZONES: The system can be divided into a maximum of three zones. A CAR or Super CAR can be used to control one zone (instead of an On-Off room thermostat): in that case terminals 13 and 14 on terminal block "M3" of the zone control unit must be left free, while the CAR or Super CAR is connected to the boiler terminal block, observing the + and - polarity. Each zone is fitted with a circulation pump , which can deliver a high flow rate.
In radiator zones the zone pumps may be connected either on the flow into the zone or on the return from the zone (so we are dealing only with the temperature of the medium being pumped). In zones with radiant surfaces (e.g. underfloor heating) the zone circulation pumps are installed on the flow into the zone, with the mixing valve upstream of the pump. The "common" port of the mixing valve is connected upstream of the pump. If the temperature in the underfloor heating zones is controlled by On-Off room thermostats, the safety thermostat contact must be wired in series with the room thermostat contact. If the underfloor heating zone is controlled by a CAR or Super CAR remote control, the safety thermostat contact must be wired in series with the zone pump.
Installation with mixed zones:
• radiators served by zone pumps (high flow rate)
• underfloor heating with thermostatic mixing valves
Connection to a boiler that is NOT prepared for a zone control unit
BOILER: This layout can be used for boilers that are not designed for connection of a zone control unit.
ZONES: With this arrangement an unlimited number of zones is permitted. None of them can be controlled by a CAR or Super CAR remote control.
All zones are served by circulation pumps: this type of installation is therefore intended for situations where a high flow rate has to be ensured in every zone.
The zone pumps can be powered through their respective room thermostats even when the boiler is set to summer mode or to DHW priority: this has no adverse effect on the operation of the boiler, but it is nevertheless advisable to switch the zone pumps off during summer mode. In radiator zones the zone pumps may be connected on the flow as well as on the return from the zone (so we are dealing only with the temperature of the medium being pumped). In zones with radiant surfaces (underfloor heating) the zone pumps are installed on the flow into the zone, and the mixing valve must be upstream of the pump.
The "common" port of the mixing valve is connected upstream of the pump. The safety thermostat contact must be wired in series with the contact of the relevant room thermostat.