PEERLESS PUREFIRE PFW-199, Installation, Operation & Maintenance Manual

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d. Dependent Boiler Designation: Dependent boilers
must have different boiler addresses “2” to “8”.
Each dependent boiler must be connected to a
circulating pump. Table 8.11 shows address
selections for Stand-alone, Managing &
Dependent boilers.
e. Cascade Operation: When a call for hot water is
present, either from a thermostat or a by sensing
low tank temperature, the master boiler chooses a
lead boiler based on the Cascade Rotation Interval
(See Below).
• The control starts the lead boiler. After the
start delay time, each boiler in the cascade
system is started in succession.
The default value of this parameter is the
minimum to prevent a long delay before
starting another boiler. If the delay is
significant, it is possible that the tank
temperature will fall before all boilers are in
operation. If many boilers are installed and the
load is highly variable, consider using two
cascade systems. In this case, the tank sensors
for each system can be placed such that the
second group of boilers only comes on if there
is a very large load.
Figure 8.54: Cascade Address Selection
C A S C A D E
A d d r e s s S e l e c t i o n
B o i l e r A d d r e s s : 0 ▼
Parameter
Stand-alone
(Default)
Managing
Boiler
Dependent
Boilers
Boiler Address 0 1 2-8
Table 8.11: Boiler Address Selection Range
Figure 8.55: Start Delay Time
C A S C A D E ▲
S t a r t D e l a y T i m e :
1 0 s e c ▼
Parameter Minimum Default Maximum
Start Delay Time 10 seconds 10 seconds
240 seconds
(4 minutes)
Table 8.12: Start Delay Time Range
41
BOILER CONTROL: INTERNAL WIRING & OPERATION
Figure 8.52: Interconnection of Cascade Link Wires
Figure 8.53: Switching the Master Switch to the
“ON” position