57
MIN setting in the ADJUST menu of the VERSA
IC
®
Control will serve to truncate the lower tem-
perature range of the EMS signal while the
TARGET MAX setting will serve to truncate the
upper range of the EMS signal (see page 59).
Example:
An MVB H7-2003A has a set-point
range based on the ID card of 50°F to 220°F (1
VDC =50°F & 10 VDC=220°F). If the Target MIN
setting is increased to 140°F and the TARGET
MAX is reduced to 180°F the boiler will respond
to a EMS signal as follows. With a contact clo-
sure at the ENABLE terminals and a 1 VDC
input signal to the boiler a call for heat will be
generated to maintain the system at 140°F sys-
tem temperature (for 10 VDC a CFH will
maintain 180°F).
The VERSA IC
®
Control will determine the firing
rate required to achieve the designated target
temperature provided from the EMS.
•
Rate Control: Firing-rate control will not
work with a multi-boiler cascade arrange-
ment.
Multi-boiler systems require each boiler
to be driven individually when wanting to provide
firing rate control from an EMS or multi-boiler
sequencer
such
as
our
Raypak
TempTra Hybrid. When configured to
allow an energy management system to provide
a burner firing rate input to the VERSA IC
®
Control, the control requires both a contact clo-
sure at the enable/disable connection as well as
a DC voltage input to allow the boiler to fire. The
minimum voltage required to fire the burner is
1.0 VDC (5.6mA) which also equates to low fire.
A voltage of 10 VDC (20mA) equates to a call for
full fire. To turn off the burner the EMS will need
to open the contact across the enable/disable.
Reducing the voltage input signal below. 88
VDC (5.3mA) will also shut off the active burner
call. When operating in response to a firing rate
input from an EMS the VERSA IC
®
Control does
not provide temperature control of the system,
however will still provide Max Delta T functional-
ity as well as Manual High Limit operation. The
EMS system is now fully responsible for supply
water temperature control as well as managing
minimum cycle times to prevent short cycling of
the equipment.
Cascade Set-up and Operation
The VERSA IC
®
system has the capability of control-
ling the operation of up to 4 heaters without the
addition of an external sequencing controller. In order
to establish a cascade system, one heater needs to
have the VERSA IC
®
Control DIP switch #2 set to the
ON position to be recognized as the Master heater in
the system. On all other heaters, turn OFF VERSA
®
DIP switch #2 so the system recognizes them as fol-
lowers. In addition, communication wire needs to run
from the J3 connections on each follower PIM™ (min-
imum 22AWG twisted pair wire) to the CN2 terminals
on the VERSA
®
board on the Master heater. Once the
field wiring is installed as per the instructions remem-
ber to enable each of the Follower units within the
SETUP menu on the Master. Once enabled within the
VERSA IC
®
control system it is now possible to view
the individual boiler data at the Master boiler as well as
for the Master boiler to begin using the Followers to
answer any heat requests from the system.
Wiring the Cascade System
Communication Bus
Designate the primary boiler as the master boiler/boil-
er 1 by leaving DIP switch #2 on the VERSA IC
®
board
in the ON position. All other connected units must have
their VERSA
®
DIP switch #2 OFF to designate them
as followers. Follower VERSA
®
boards are ignored by
their corresponding PIM™ Modules. Use minimum of
22 AWG wire to connect the master VERSA
®
board to
the PIM™ on the followers. Up to 3 followers can be
connected to the VERSA
®
Master. For systems requir-
ing more than 4 connected boilers, an external
sequencer such as the Raypak TempTra
Hybrid can be used.
It is recommended that the shortest length cable pos-
sible be used to reach between the boilers. Do not run
unprotected cables across the floor or where they will
become wet or damaged. Do not run communication
cables in parallel with, or close to or against, high volt-
age (120 VAC or greater) wiring. Raypak recommends
that the total maximum length of each set of communi-
!"
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Fig. 40: VERSA
®
0-10 VDC Chart
Summary of Contents for 5000.72A
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