23
MASTER
Fig. 22: MODE 3 Hydronic Multi - Boiler with Indirect DHW on system
Maximum distance not to exceed 4 pipe
diameters or 12” whichever is less
below the minimum acceptable level as defined in the
Installation and Operating manual for the product
being installed.(See page 43).
The Boiler Pump (P1) runs during any call for burner
operation and is delayed “off” as user-defined in the
BOILER menu after the burner has shut down. The
System Pump (P2) runs whenever the system is
enabled for heating and the outdoor air temperature is
lower than the WWSD temperature setting (if utilized).
An indirect DHW call-for-heat will toggle the System
Pump (P2) off until the indirect call-for-heat is satisfied
or the priority timer has elapsed allowing the system to
return to heating mode. The Indirect DHW Pump (P3)
runs during an indirect call-for-heat with no “off” delay.
The System Pump is delayed “off” as user-defined in
the SETUP menu.
Mode 3 is used for this configuration. Ensure DIP
switches #1 and 2 on the VERSA
®
Control Board are
in the ON position to make programming changes.
Prior to setting any DIP switches, the heater must be
turned off.
MODE 3 Cascade
The following diagrams will show cascade systems (up
to 4 boilers maximum) with and without CWP in con-
junction with an indirect DHW demand located on the
system loop. The CWP diagrams will show either an
individual 3-way valve at the boiler (MIX Type = BOIL)
or a single 3-way valve providing CWP to all connect-
ed boilers within the cascade (MIX Type = PLNT). The
following piping configurations can be used as fixed
set-point or set up to work in conjunction with an
Outdoor Air Reset Sensor connected to the Master
boiler (S4a) to adjust the target water temperature as
the outdoor air temperature changes.
Reverse/return piping is shown and is recommended
to ensure balanced flow through each of the connect-
ed boilers. Primary/secondary piping is the only
method supported by Raypak to ensure proper boiler
and system functionality while achieving maximum
system efficiency.
NOTE:
0-10VDC firing rate control ignores all
functions except Max Delta T, CWP, Limit and Safety
Switches.
Summary of Contents for 5000.72A
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