Tft Series Installation and Operation Instructions
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Trinity
35
Table 9-2 Minimum and Maximum Modulation Rates
Model
Min. Modulation Rate (RPM)
Max. Modulation Rate (RPM)
Tft60
1525
4650
Tft85
1525
6300
Tft110
1625
7000
Tft154
1740
7980 (7500 – LP)
Tft201
1450
8000
Tft285
1000
7300
Tft340
1100
6650
Tft399
1
1050
7800 (7500 – LP)
Notes:
1
Modulation rates specified for model Tft399 are for units with serial numbers greater than
90974; consult earlier instruction manuals for modulation rates for earlier serial numbers.
Carbon Monoxide
- Never leave the unit operating while producing Carbon Monoxide
(CO) concentrations in excess of 175ppm. Failure to follow this warning may result in
serious injury or death.
Manifold Pressure
- DO NOT adjust or measure the Manifold Pressure of the boiler.
Correct manifold pressure is factory set. Field adjustment could result in improper burner
operation resulting in fire, explosion, property damage or death.
Adjustments to the Throttle/Input Adjustment Screw may only be made by a qualified
gas technician, while using a calibrated combustion analyzer capable of measuring CO
2
and CO. Adjustments may only be performed if the gas line pressure is maintained above
minimum levels throughout the duration of the test, see Table 9-1. Failure to follow these
instructions may result in serious injury or death.
Adjustment
Throttle / Input Screw Adjustments -
The boiler is equipped with a Throttle/Input Adjustment Screw, located
on the Gas Valve. It is used to adjust the flow of gas leaving the gas valve entering the Venturi and then the
combustion air stream. Turn the Throttle screw in (clockwise) to reduce the flow of gas, make combustion
leaner, and reduce the concentration of CO
2
in the flue gases. Turn the Throttle screw out (counterclockwise)
to increase the CO
2
level and flow of gas in the combustion air stream.
Typical adjustment required is 0-1/2 of
a turn in or out from the factory setting. See Figures 9-1 to 9-3 for Throttle screw location and Table 9-1 for
appropriate CO
2
levels.
Combustion Calibration
- To calibrate burner operation, perform the following procedure using a calibrated
combustion analyzer capable of measuring CO
2
and CO from Natural and Propane Gas burning boilers:
1.
Operate the unit at the maximum modulation rate, see Table 9-2.
2.
Ensure the gas line pressure is maintained within tolerance, see Table 9-1.
3.
While at the maximum modulation rate, measure the CO
2
and CO; adjust as necessary, using the Throttle
Screw, to be within the limits listed in Table 9-1.
4.
Operate the unit at the minimum modulation rate (Table 9-2). Ensure the combustion remains smooth and
CO
2
and CO remain within the limits (Table 9-1). If not, do not adjust further, contact NTI for assistance.
Throttle/Input Adjustment Screw
Increase gas
Turn Counter Clockwise
Decrease gas
Turn Clockwise
