Tft Series Installation and Operation Instructions
│
Trinity
51
Lead Lag Instructions - Common
Plumbing
– install as many as 8 Tft boilers in parallel in a primary/secondary plumbing configuration as
illustrated in Figure 11-1. Size common piping as per Table 11-1.
Boiler Pump
– each boiler must have its own circulator (see Figure 11-1) which is controlled by its
PUMP B
output; see
Field Wiring
Figure 12-1 and Table 12-1. The Boiler Pump must be sized according to Table 10-4.
Communication Wiring
– using 3-wire cable, daisy-chain terminals
DATA +
,
DATA –
and
DATA COM
of each
boiler in parallel; see
Field Wiring
Table 12-2a and Figure 12-2.
System Sensor (Optional)
– install a system sensor (NTI P/N: 84010) on the outlet (supply) pipe feeding the
heating system, see Figure 11-1. Wire the system sensor to
SENSOR COM
and
SYSTEM
of the Master Boiler;
see
Field Wiring
Table 12-2a and Figure 12-2. The system sensor automatically becomes the modulation
sensor for the boiler system, i.e. the control attempts to achieve setpoint temperature at the location of the
sensor. If a system sensor is
NOT
used, at the Master boiler set the applicable sensor input to
Unconfigured
as follows:
Configure
– Sensor Configuration – S10 (J10-7) sensor
Outdoor Sensor (Optional)
– wire the outdoor sensor to
SENSOR COM
and
OUTDOOR
of any one of the
boilers in the cascade; see
Field Wiring
Table 12-2a and Figure 12-2. Note: only one outdoor sensor is
needed for the multiple boiler system.
Modbus Address –
assign a unique
MB2 Modbus Address
to each boiler in the cascade. Access the
MB2
Modbus Address
setting via the
System Identification & Access
menu as follows:
Configure
– System Identification & Access – MB2 Modbus Address
Master Enable
– choose
one
(and only one) boiler in the cascade to be the Master, this boiler will receive all
control wiring and will be used for setting control parameters (see steps below). On this one boiler, set
Master enable
equal to
Enabled
via the
Lead Lag Master Configuration
menu, accessed as follows:
Configure
– Lead Lag Master Configuration – Master enable
Table 11-1
Minimum Pipe Sizes for Multiple Boiler Applications
# of
Units
Tft60
Tft85
Tft110
Tft154
Tft175
Tft201
Tft285
Tft340
Tft399
Pipe Size
2
1”
1-1/4”
1-1/2”
1-1/2”
2”
2”
2”
2-1/2”
2-1/2”
3
1-1/4”
1-1/2”
2”
2”
2”
2-1/2”
2-1/2”
3”
3”
4
1-1/2”
2”
2”
2-1/2”
2-1/2”
2-1/2”
3”
3”
3”
5
1-1/2”
2”
2-1/2”
2-1/2”
3”
3”
4”
4”
4”
6
2”
2”
2-1/2”
3”
3”
4”
4”
4”
5”
7
2”
2-1/2”
2-1/2”
3”
4”
4”
4”
5”
5”
8
2”
2-1/2”
3”
3”
4”
4”
4”
5”
5”
Note: Minimum pipe size based on assumed temperature rise of 25ºF at maximum firing rate.
