Free ZSR103 3 Zone Pump Control

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Free ZSR104 4 Zone Pump Control

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Free ZSR106 6 Zone Pump Control

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Caleffi ZSR Single Zone Switching Relay Box- Space Heating & DHW

Caleffi ZSR103, ZSR104 and ZSR106 are multi-zone pump and boiler operation control switching relay box.


The zone box “talks” to low voltage thermostats(24V, dry contact) and has DHW priority function.

When any of zones call for heat, the corresponding zone pump relays are ON as well as priority pump relay. LED indicator lights up.

The dry contact AUX, XX closes when any of zones calls for heat. XX connects to boiler TT terminals, AUX may be used as dry-contact signal for other control purpose.

DHW priority can be set up by the dip switch, Dry contact Zone 1E/S closes whenever DHW calls for demand.

Switching relay box is expandable via D,P & Ground terminals.

Power supply:  120 VAC 50/60 Hz
Transformer voltage:  24 VAC
Max transformer load: 
    12 VA (ZSR103 and ZSR104)
    20 VA (ZSR106)

Electrical switch rating:  20 A max combined
Electrical switch rating pump output:  120 VAC, 5 A each

Dry contact rating (AUX, XX, ZONE1 E/S):  120 VAC max, 2 A each

Replaceable fuses:  Type 2AG, 5 A slow blow

ICON of PDF  Brief Technical Specification                      ICON of PDF Wiring Guide and Application Examples

  • Example-1
  • Example-2_edit
  • Example-3
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