Crown Boiler BWF061 - Manual (Page 33)

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Wiring Variations
1) Multiple Circulator Zones – Figure 33 shows wiring for two or more circulator zones using Honeywell R845As. One
fewer R845A is used than the total number of circulator zones. A DPST Honeywell RA832A may be substituted in place
of the R845A using the “X” and “X” terminals in place of the “5” and “6” terminals on a R845A.
A call for heat from the “zone #1” thermostat causes the zone #1 circulator to start and the boiler to fire exactly as in a
single zone system (see “Sequence of Operation”). A call for heat from any other thermostat will energize the DPST relay
in that zone’s R845A. When this relay is energized, electrical continuity is created between terminals 3 and 4, energizing
the circulator for that zone. At the same time, electrical continuity is created between terminals 5 and 6 on the R845A,
creating a current path from terminal “R” to “Y” on the R8285 fan center in the BWF. Assuming that the supply water
temperature is below the high limit setting, the normal ignition sequence will be initiated. If this happens when there is no
call from the zone #1 thermostat, the relay on the R8285A will not be energized and the zone #1 circulator will remain
off.
2) Multiple Zones using Zone Valves – Figure 34 shows wiring for multiple zones using Honeywell V8043F zone valves.
This wiring diagram may be used for other 24-volt zone valves as long as they are equipped with end switches. Do not
attempt to use the transformer on the R8285 to power the zone valves; use a separate transformer. Up to five V8043Fs
may be powered by one 48VA transformer, such as the Honeywell AT87A.
A call for heat from a given thermostat will result in the application of 24 volts across the TH and TR terminals on the
corresponding zone valve, energizing the zone valve motor. The zone valve opens and the end switch contacts are then
made. The end switches are connected in parallel with each other and to the BWF “thermostat” connections so that any
zone valve that opens will also start the circulator and fire the boiler (assuming the high limit is not open). Zone valve
terminal TH/TR has no internal connection on the zone valve; it is merely a “binding post” used to connect two or more
wires.