Tx I&O Manual │Gas Valve and Burner Set-up
9.0 GAS VALVE AND BURNER SET-UP
Set-up of the Trinity Tx gas valve must be performed by a licensed Gas Technician.
Failure to perform the set-up correctly may result in incorrect operation, component
failure, property damage, serious injury or death.
Combustion Calibration Procedure
To calibrate burner combustion, perform the following procedure using a calibrated combustion analyzer
capable of measuring CO
2
and CO from a Natural Gas or Propane burning appliance:
1. Set analyzer to the appropriate fuel (Natural Gas or Propane).
2. Gas Line Pressure Test – monitor gas line pressure throughout all combustion tests and verify it is
maintained within tolerance. See Gas Line Pressure Test below.
3. Set Throttle Screw – operate burner to the maximum modulation rate (see Table 9-2); set combustion
according to Table 9-1 using the Throttle Screw; allow time for the analyzer readings to stabilize between
adjustments – record CO
2
value. See Throttle Screw Adjustment below.
4. Set Offset Screw – operate burner to the minimum modulation rate (see Table 9-2); using the Offset Screw,
set the CO
2
to 0.4-0.8% lower than the value obtained during the maximum modulation rate test (e.g. if CO
2
at Max = 9.5%, then CO
2
at Min must = 8.8-9.1%). See Offset Screw Adjustment below.
Combustion Calibration is mandatory upon installation and during each annual
service. Failure to perform the Combustion Calibration in accordance with these
instructions may result in incorrect combustion leading to burner damage or excessive
Carbon Monoxide concentrations causing property damage, personal injury or death.
Carbon Monoxide - Never leave the unit operating while producing Carbon Monoxide
(CO) concentrations in excess of 175 ppm. Failure to follow this warning may result in
serious injury or death.
Throttle Screw Adjustment
The gas valve Throttle Screw (see Figures 9-1 & 9-2) is used to calibrate the CO
2
concentration with the burner
operating at or near the maximum modulation rate (see Table 9-2). Turning the Throttle Screw in (clockwise)
decreases the CO
2
concentration. Turning the Throttle Screw out (counterclockwise) increases the CO
2
concentration. Typical adjustment required is 0 –
1
/
2
of a turn in or out from the factory setting.
NOTE: Calibration of the Throttle Screw should only be performed with the burner operating at or near the
maximum modulation rate (see Table 9-2).
Adjustments to the Throttle Screw may only be made by a qualified gas technician
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.
Offset Screw Adjustment
The gas valve Offset Screw (see Figures 9-1 & 9-2) is used to calibrate the CO
2
offset at minimum modulation
vs. maximum modulation. Turning the Offset Screw in (clockwise) increases the CO
2
concentration at minimum
modulation rate. Turning the Offset Screw out (counterclockwise) decreases the CO
2
concentration at minimum
modulation rate. Typical adjustment required is 0 -
1
/
8
th
of a turn in or out from the factory setting.
NOTE: Calibration of the Offset Screw must only be performed with the burner operating at the minimum
modulation rate (see Table 9-2).
Adjustments to the Offset Screw may only be made by a qualified gas technician using a
calibrated combustion analyzer capable of measuring CO
2
and CO, and only with the
burner at the minimum modulation rate (see Table 9-2). Attempting to set the Offset
Screw while the burner is operating at a modulation rate other than the minimum will
result in incorrect combustion and may lead to burner damage or excessive CO.
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