45
110331-07 - 8/23
PHTM II
Combi Installation, Operating & Service Instructions
Figure 13-4: Boiler-to-Boiler Connections
X4
X5
X6
BCC
X2
Fuses
X1
X3
XB-2
XB-1
RJ45 Connections (2)
13
Field Wiring
(continued)
2. External power must not be applied to any low
voltage terminals - doing so may damage boiler
control. Note following:
A. Heat T'Stat (field supplied) - Connect room
thermostat or zone panel end switch (isolated
contact only) to "Heat T'stat" terminals.
B. Aux T'Stat - Connect jumper, common
recirculation timer (field supplied) or point
of use push button (field supplied). Auxiliary
T'Stat can also be used for 2nd zone or
indirect demand. Refer to Table 16-13
for explanation.
C. External Limit: External limit terminals are
intended for use with field supplied safety
device, such as a manual reset high limit or
LWCO. When an external limit is used,
jumper between these two terminals must be
removed.
D. Outdoor Sensor - Use only Tasseron TSA00AA
(P/N 108681-01) 10k outdoor sensor. When
optional sensor is connected, boiler
control will provide outdoor air sensor based
freeze protection interlocks. When placing
sensor, consider following:
i
. Locate sensor on outside of building.
ii
. Avoid placing sensor in areas where it may
be covered with ice or snow.
iii
. Avoid direct radiation from sun.
iv
. Avoid placing sensor near potential
sources of electrical noise such as
transformers, power lines, and fluorescent
lighting.
v
. Wire sensor to boiler using minimum 22
AWG wire.
vi.
Where electrical noise sources cannot be
avoided, wire sensor using 2 conductor,
UL Type CM, AWM Style 2092 shielded
cable. Connect one end of shielding on
this cable to ground.
E. Recirculation (Header) Temperature
Sensor - When optional sensor is
installed and Recirculation (Comfort)
Mode is enabled, boiler will attempt to
maintain target domestic hot water
recirculation temperature in recirculation
piping. Use only Honeywell 32003971-
003 (P/N 108703-01) sensor. Locate sensor as
shown in Figure 11-3. Wire sensor using a 2
conductor, UL Type CM, AWM Style 2092,
300 Volt 60°C shielded cable. Connect
one end of shielding on this cable to ground.
See Table 16-11 for information on enabling
recirculation sensor.
F. LWCO wiring - Although not necessary to
protect this boiler, some jurisdictions may
require installation of LWCO with this boiler.
i
. Refer to Section 10 Heating System Piping
for LWCO kits available from manufacturer.
ii
. LWCO from these kits is installed to
4 pin connector on Low Voltage
Connections terminal strip.
G. RJ45 Connections - Boiler-to-Boiler
communication network is used for multiple
boiler ("Lead-Lag") installations.
Note: Combi boilers may only be used as
slaves in such a system. Refer to Table 16-16
for information on enabling this feature.
Boiler lead/lag sequencer connection is made
directly to control. Refer to Figure 13-4.