AERCO Boiler Valve Controller (BVC) PRIOR to Serial-12-840-1 - Manual (Page 8)

GENERAL INFORMATION
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Figure 1 - The AERCO Boiler Valve Controller Box
1.4 USE OF THE BOILER VALVE CONTROLLER
There are two basic purposes of the BVCs. They are as follows.
1. Reduce the required minimum system water flow to minimal single boiler flow.
2. Eliminate the need for a boiler bypass flow path by being able to open up flow through the
boilers when system demand is satisfied, thereby preventing system pump dead head
conditions.
1.5 TRIGGERED VERSUS MANUAL OPERATION
The BVC operates in two modes; automated and manual. The automated mode runs without
operator intervention. Depending on the operational status of the boilers, voltages are applied to
the BVC electronic input terminals, causing the MOVs to open or close as appropriate.
The BVC may also be used manually to open and close the boiler valves as desired. For
instance, if only one of the boilers in a four boiler system is firing, it may be desirable to open
the valves on the remaining three (non-firing) boilers. This allows water circulation
commensurate with the flow requirements of the system supply heat circulation pump.
Should the BVC be used manually to change the open/close state of a MOV, the MOV may
subsequently have its open/close state changed either manually or automatically, in accordance
with the boiler system valve state open/close operational rules.