Raypak RSIT30 Installation & Operating Instructions Manual page 12

Figure 7 is a controls diagram for a boiler that is always
on, maintaining hot water in the boiler loop. The aquas-
tat turns on a circulator to induce boiler water flow
through the indirect water heater.
FIELD
INSTALLED
24VAC
Boiler Maintaining 180ºF
Fig. 7:
Cold-Start Boiler
Fig. 8:
Figure 8 depicts wiring the indirect water heater to a
cold-start boiler system using a Honeywell RS845. In
this type of system, the boiler does not run unless there
is a call for heat in one of the zones of the system. When
connecting to a cold-start boiler, always remember that
in principle an indirect water heater operates as another
heating zone. The difference is that when the indirect
water heater calls for heat, the indirect water heater cir-
culator must start rather than opening a zone valve; the
system circulator stays off, and the boiler must light to
reach Operating Temperature.
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