Raypak VERSA IC, Инструкция по установке и эксплуатации

Страница: 18 / 80

18
A
B
AB
MASTER
Fig. 19: MODE 2 Hydronic Multi-Boiler with Indirect DHW on system, with CWP (MIX TYPE = PLNT)
The system can also be set to operate the indirect
DHW call with or without priority. The system temper-
ature will be controlled by the System Sensor
connected to the Master (S3a) during a call for hydron-
ic heat or an indirect call. See
System Sensor
Installation
on page 9. The Indirect DHW Sensor
(S5a) determines the indirect call based on the user-
defined set-point. The VERSA IC
®
control system also
allows for a thermostat controller (tank-stat) to be
mounted in the indirect tank and provide a call for indi-
rect operation via contact closure in lieu of the tank
sensor. The thermostat wiring connection is at the field
wiring strip on MVB/XTherm, or the Master PIM™ J1
terminal block at terminals 8 and 10. When using an
indirect DHW sensor to control tank temperature, con-
tact closure is required across the indirect override
connections for proper operation (see IND Sensor,
page 42 for further details). To ensure proper operation
during "limp-along" mode connect an aqua-stat across
the indirect DHW override terminals of master unit,
install jumper across indirect DHW terminals of follow-
er units and set the rest of the follower PIM™'s
operator dial to be equal to DHW Target temperature.
In lieu of aquastat across the indirect DHW override
terminals of the master unit a jumper may be used.
This configuration requires all PIM™ operator dials be
set to DHW Target temperature to prevent an over-
temp condition from occurring during "limp-along".
It is also recommended the system pump and DHW
pump be connected in parallel from each cascade fol-
lower, to allow these pumps to be functional during
limp-along operation.
During an indirect call-for-heat with or without priority
selected, the cascade firing rate is determined by the
System Supply Sensor (S3a) temperature. The
VERSA IC
®
will provide Max Delta T control to cycle
the burner if the Max Delta T is exceeded between
Boiler Outlet Sensors (S1a-b-c-d) and Boiler Inlet
Sensors (S2a-b-c-d).
In order to enable MIX settings, VERSA
®
DIP #3 must
be set to ON position. Raypak’s Cold Water protection
system utilizes a proportional 3-way valve to bypass
water from the boiler outlets to the inlets (S2 a-b-c-d)
during operation, when the system return water tem-
perature is below the minimum acceptable level,
among all active units, as defined in the Installation
and Operating manual for the product being installed.
Priority mode toggles off the System Pump (P2a)
when an indirect call-for-heat is present. Boiler Pumps
(P1a-b-c-d) run in conjunction with their associated
burner during all heat calls regardless of priority. The
Indirect DHW pump (P3a) runs during an indirect call-
for-heat with no “off” delay. The Boiler Pumps
(P1a-b-c-d) are delay “off” as user-defined in the BOIL-
ER menu and System Pump (P2a) is delay “off” in the
SETUP menu. The System Pump (P2a) runs whenev-
er the system is enabled for heating and the outdoor
air temperature is lower than the WWSD temperature
setting (if utilized) unless an indirect call-for-heat is
present with priority.
Mode 2 is used for this configuration. Ensure DIP
switches #1 and 2 on the VERSA
®
Master Control
Board are in the ON position to make programming
changes. Prior to setting any DIP switches the heater
must be turned off. It is important to remember to
Maximum distance not to exceed 4 pipe
diameters or 12” whichever is less