Trinity
│
Installation and Operation Instructions
Tft Series
44
Boiler System Plumbing
The Trinity Tft boiler uses a low mass heat exchanger that requires a minimum rate of forced water circulation
any time the burner is operating (See Table 10-2 for minimum flow rate requirements). To ensure the minimum
flow rate is attained, NTI strongly recommends installing the boiler in a “Primary/Secondary” plumbing
configuration utilizing “Closely Spaced Tees” or a “Low Loss Header” to de-couple the Boiler-Primary loop
from the System-Secondary loop(s). See the examples of Primary/Secondary Loop configurations in Figures 10-
5 and 10-6.
Table 10-2 Minimum Flow Rate Requirements
Model
Flow (US gpm)
Model
Flow (US gpm)
Tft60
3
Tft201
7.5
Tft85
3.5
Tft285
11
Tft110
4
Tft340
13
Tft154
6
Tft399
15
System Components –
As a minimum, a properly installed system will include the following major components
identified in Table 10-3.
Table 10-3
System Major Component Checklist
Factory Supplied
Components
Field Supplied Components
Pressure Relief Valve
Boiler Loop Circulator (Pump B in Figure 10-5 or Pump C in Figure 10-6)
Pressure/Temperature Gauge
DHW Loop Circulator (Pump A in Figure 10-5 and Figure 10-6, for applications
utilizing and Indirect Fired Water Heater)
Auto Air Vent
Central Heat (CH) Loop Circulator(s)
(CH Circulator - Pump C in Figure 10-5; Zone Circulators in Figure 10-6)
Central Air Removal Devices (i.e. Micro Bubbler or Air-Scoop)
Pressure Regulating “Fill Valve”
Backflow Preventer
Expansion Tank
Circulating Pumps
– Trinity Tft boilers are equipped with three 120VAC pump outputs:
1.
PUMP A
“DHW Pump” - operates during a Domestic Hot Water demand (DHW).
2.
PUMP B
“Boiler Pump” - operates during any demand.
3.
PUMP C
“CH Pump”
- operates during a Central Heat/Thermostat demand (THERMOSTAT).
Ensure pumps are oriented as per the manufacturers’ instructions. Wiring of these circulators will depend on the
system configuration selected; see Figures 10-5 and 10-6. For further wiring details see Section 12.0.
Circulators responsible for forcing the water flow through the boiler must be sized
according to Table 10-4. Pump recommendations are based on a Primary/Secondary
plumbing configuration (see Figures 10-5 and 10-6) using the listed pipe size in the
Boiler-Primary Loop, with up to 50 equivalent feet of pipe length. The installer is
responsible for sizing the boiler circulator(s) and piping for applications using non
Primary/Secondary plumbing; Figure 10-4 provides Head Loss curves for this purpose.
Failure to ensure the minimum water flow rate through the boiler when the burner is
operating will result in “short-cycling”, reduced performance and operating efficiency,
and may also cause overheating and premature failure which will void the warranty.
Failure to follow instructions may result in fire, property damage, serious injury or death.
