Slant/Fin CHS-399 - Manual (Page 34)

Slant Fin Corp. │ Installation and Operation Instructions CHS Series
34
9.0 GAS VALVE AND BURNER SET-UP
Set-up of the CHS 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.
Gas Line Pressure
The boiler gas valve is equipped with a line pressure test port; see Figures 9-1 and 9-2. Use the following
procedure to measure the gas line pressure to the boiler to ensure if falls within the range given in Table 9-1:
1. Turn the supply of gas to the boiler off.
2. Open the bleed screw of the line pressure test port approximately 1-1/2 turns. This port is directly
connected to the gas line feeding the boiler. See Figures 9-1 and 9-2.
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 boiler 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 application 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, in case
adjustments need to be made.
9. Complete pressure testing, and then return the bleed screw of the Line Pressure Test Port to the closed
position.
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 boiler
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
(%)* CO (ppm)
Max.* Nominal/Desired Min. Max. Min. Max.
Natural 7 4 10.5 8.7 9.7 175
Propane 11 8 13 10.5 11.5 175
*Note: Observe the combustion products with the burner operating at the maximum modulation rate.
Table 9-2 Minimum and Maximum Modulation Rates
Model Min. Modulation Rate (RPM) Max. Modulation Rate (RPM)
CHS-85 1525 (1700 on LP) 6300
CHS-110 1625 (2150 on LP) 7000
CHS-155 900 3700
CHS-175 900 4100
CHS-200 900 4650
CHS-250 900 5900
CHS-300 1500 5000 (4800 on LP)
CHS-399 1500 6900 (6600 on LP)
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.