Ariston System A 24 RFF, System A 30 RFF 13. Electrical Connections

29
FIG. 38
13. Electrical Connections (continued)
13.2 Connecting Zone Valves (System A)
The boiler can be connected to a central heating system that uses
two zone valves to allow connection to an indirect storage cylinder.
There are two wiring diagrams shown, one for the connection to an
Unvented Cylinder (Diagram. A) and one for connection to an open
vented cylinder (Diagram B).
In both cases the boiler connection is shown as ROOM, which
relates to the terminal on the PCB for external controls (see 12F IG.
31).
When connecting the boiler to an external cylinder do not run 240V
cables and the cables for the ROOM terminal (Fig. 38) together, use
separate cables to prevent induced voltage on the low voltage
switching circuit.
NOTE:THEUSEOFA‘Y’ PLAN SYSTEM IS NOT POSSIBLE WITH THE
SYSTEM A BOILER DUE TO THE LOW VOLTAGE SWITCHING OF THE
APPLIANCE.
* IMPORTANT!!
ENSURETHAT A BALANCING VALVE IS FITTED ON THE
CYLINDERRETURN AND BALANCED CORRECTLY AT
COMMISSIONINGSTAGE.
*