Section IV: Installation (cont..)
electrical connections
Indirect
IndirectCirculator
Aquastat
L1 HOT 
120 VOLT
L2 NEUTRAL
Figure 9: Boiler Maintaining 180°F
Figures 9 and 10 are general wiring diagrams. For a maintaining temperature boiler, Figure 9 should closely match your system. For cold start boilers your wiring may resemble Figure 10, but will vary depending on the boiler type and controls or relays used. It is not possible to list all wiring
variations here. When connecting to a cold start boiler, always remember that in principle an indirect water heater operates as another heating zone. The difference is when the indirect water heater calls for heat, the indirect water heater circulator must start rather than opening a zone valve; the system circulator stays off; and the boiler must light to reach high limit.
WIRING NOTES:
1. Dashed lines indicate low voltage (24 VAC)
L1 HOT
120 VOLT
L2 NEUTRAL
Indirect
Aquastat
Burner
Control
Indirect Circulator
R845 Relay or Equivalent
2. Use jumper wire between terminals #1 and #3 on R845 relay
THERMOSTAT SPECIFICATIONS:
Thermostats can operate at low or line voltages.
24 volt | N/A |
120 volt | 8 amp |
240 volt | 5 amp |
This equipment must be properly grounded to prevent a potential shock hazard, and to reduce deterioration of the anode due to electrolysis. Refer to local electrical codes and ordinances.
Figure 10: Cold Start Boiler
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