Trinity Lx
│
Installation and Operation Instructions
Lx – WH Series
38
Adjustment
Input Screw Adjustments -
The water heater is equipped with a Throttle/Input Adjustment Screw, located on
the Gas Valve and Venturi Assembly. The Throttle screw is used to adjust the flow of gas leaving the gas
valve, entering the Venturi and hence entering the combustion air stream. By turning the adjustment screw in,
clockwise, the flow of gas is reduced and the combustion becomes leaner, thus reducing the concentration of
CO
2
in the flue gases. To increase the CO
2
the Throttle screw must be adjusted out, counterclockwise, thus
increasing the flow of gas from the gas valve to the combustion air stream. See Figure 9-5 for screw direction.
Lx200WH & Lx300WH Adjustments -
The throttle screw for models Lx200WH & Lx300WH is a multiple
turn valve. Typical adjustment required for Natural Gas is 0-1 full turns in or out from the factory setting.
Typical adjustment for LP Gas is 0-3 full turns in or out from the factory setting upon inserting the LP orifice
as per the applicable Propane conversion instructions. See Figure 9-1 for throttle screw location.
Lx400WH Adjustments -
The throttle screw for the Lx400WH is a geared valve with a 4:1 ratio. Adjusting the
throttle screw 4 complete turns will return the valve to the original location, 2 turns from fully open will
completely close the valve. Typical adjustment required is 0-1/4 turn in or out from the factory setting. See
Figure 9-2 for throttle screw location.
Lx500WH Adjustments –
The throttle screw for the Lx500WH is a multiple turn valve. Typical adjustment
required for Natural Gas is 0-1 full turns in or out from the factory setting. To adjust combustion for Propane
Gas, turn the throttle screw all the way in (clockwise until it stops), then turn the throttle screw out
(counterclockwise) 4-1/2 turns and set with a combustion analyzer. See Figure 9-3 for throttle screw location.
Lx600WH-Lx800WH Adjustments -
Remove the cap and adjust the input screw by turning it clockwise to
decrease gas flow and counter-clockwise to increase gas flow. Typical adjustment required is 0-1/8 turns in or
out. See Figure 9-4 for throttle screw location.
Figure 9-5 Throttle/Input Adjustment Screw (All Models)
Decrease Gas -
Turn Clockwise
Increase Gas -
Turn Counter Clockwise
IF FOR ANY REASON THE INPUT SCREW IS ADJUSTED, A "COMBUSTION ANALYZER"
MUST BE USED TO ENSURE SAFE AND PROPER OPERATION OF THE GAS VALVE.
Adjustments to the Throttle screw may only be made by a qualified gas technician, while
using a calibrated combustion analyzer capable of measuring CO
2
and CO. Failure to
follow these instructions may result in serious injury or death.
Adjustments to the Throttle screw 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.
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 appliances:
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.
