Lx – WH Series Installation and Operation Instructions
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Trinity Lx
35
9.0
GAS VALVE AND BURNER SET-UP
The Trinity Lx gas valve must be set-up by a licensed Gas Technician. Improper set-up
may result in incorrect operation, damage to components or property, injury or death.
Gas Line Pressure
The water heater gas valve is equipped with a line pressure test port; see Figures 9-1 through 9-3. Use the
following procedure to measure the gas line pressure to the water heater to ensure if falls within the range given
in Table 9-1:
1.
Turn the supply of gas to the water heater off.
2.
Open the bleed screw of the line pressure test port approximately 1-1/2 turns (Lx200WH-Lx500WH
models). This port is directly connected to the gas line feeding the water heater. For Lx600WH-Lx800WH
models, replace 1/8” NPT plug in the inlet flange of the gas valve with a hose barb fitting suitable for
manometer tubing used. See Figures 9-1 through 9-4.
3.
Force 1/4
ID tubing over the housing of the line pressure test port; install the other end of the tubing to an
appropriate line pressure test gauge or manometer. Ensure both ends of the tubing make a tight connection.
4.
Open the supply of gas to the water heater and check for gas leaks.
5.
Observe the line pressure under static conditions and compare it to Table 9-1. The pressure will be greatest
under static conditions.
6.
With all other gas appliances in the applications running, operate the burner to the maximum firing rate (see
Table 9-2) and compare the observed line pressure with Table 9-1. The pressure will be lowest during the
maximum flow of gas.
7.
Adjust the gas line pressure to ensure the parameters in Table 9-1 are attained under all conditions. If
possible adjust the line pressure to the "Nominal/Desired" value listed in Table 9-1, while the unit is
operating at the maximum modulation rate, see Table 9-2.
8.
Continue observing the gas line pressure until the completion of the combustion analyses, incase
adjustments need to be made.
9.
Upon completion of the line pressure testing, return the bleed screw of the Line Pressure Test Port to the
closed position. For the Lx600-800 models, replace the installed hose barb fitting with the factory 1/8” NPT
plug; use NG/LP approved thread sealant.
The line pressure is a function of the gas supply and is affected solely by field provided
parameters such as line size and regulator settings. Under no circumstances can the water
heater gas valve influence or be used to adjust the gas line pressure.
Failure to close the bleed screw of the Line Pressure Test Port will cause a severe leakage
of gas, resulting in a fire or explosion causing property damage, serious injury or death.
Table 9-1 Line Pressure and Combustion Parameters
Gas
Line Pressure (inches wc)
CO
2
(%)
1
CO (ppm)
Max.
Nominal/Desired
Min.
Max.
Min.
Max.
Natural
7
4
2
10.5
8.8
9.8
175
Propane
11
8
13
9.8
10.8
175
Notes:
1
It is permissible to have higher CO
2
values with the burner operating at the minimum modulation rate.
2
The minimum permissible line pressure when operating with Natural Gas is 5.5 inches wc for model Lx500WH.
Table 9-2 Minimum and Maximum Modulation Rates
Modulation
Rates (rpm)
Lx200WH Lx300WH Lx400WH Lx500WH Lx600WH Lx700WH Lx800WH
Minimum
925
1250
1550
1400
1050
1250
1250
Maximum
5950
5850
7250
6400
4350
4300
5300
Carbon Monoxide
- Never leave the water heater operating if emitting Carbon Monoxide
(CO) concentrations in excess of 175ppm. Failure to comply may result in injury of death.
Manifold Pressure
- DO NOT adjust or measure the Manifold Pressure of the water
heater. Correct manifold pressure is factory set. Field adjustment could result in improper
burner operation resulting in fire, explosion, property damage or death.
