6.Compare the actual manifold gas pressure reading recorded above to the required minimum/maximum values given in Table 4 on page 13.Adjust manifold gas pressure as necessary, see the instructions that follow.
7.Record the supply gas pressure when the 24 VAC Gas Valve is energized and the Main Burner is ignited. This is a “dynamic” gas pressure reading; while the water heater is firing.
8.Compare the actual supply gas pressure reading recorded above to the required minimum/maximum values given in Table 4 on page 13. Adjust supply gas pressure as necessary, see the instructions that follow.
| MANIFOLD GAS | GAS CONTROL |
| PRESSURE REGULATOR | KNOB |
| COVER SCREW | |
|
| |
| HONEYWELL |
|
INLET | ON | OUTLET |
|
| |
| OFF | MANIFOLD GAS |
| PRESSURE TAP | |
|
| 1/8’ NPT PLUG |
| 24 VAC GAS VALVE TOP VIEW | |
Figure 56
Supply Gas Pressure Adjustment
Fire and Explosion Hazard
Do not use water heater with any gas other than the gas shown on the rating label.
Excessive gas pressure to gas valve can cause serious injury or death.
Turn off gas lines during installation.
Contact a qualified installer or service agency for installation and service.
Supply gas pressure shall be measured while the water heater is not firing (static pressure) and while the water heater is firing at full capacity (dynamic pressure).
If the supply gas pressure to the water heater is not between the required minimum and maximum values given in Table 4 on page 13 adjust the supply gas regulator as necessary. Adjust the supply gas regulator(s) per the regulator manufacturer’s instructions to achieve the required “static” and “dynamic” supply gas pressure.
Multiple Appliance Installations:
In multiple water heater installations or in installations where the installed water heater(s) share a common gas supply main with other gas fired appliances; the supply gas pressures shall be measured at each water heater with all gas fired appliances connected to a common main firing at full capacity.
On multiple water heater installations the supply gas line regulators shall be adjusted to provide gas pressure to each water heater within the minimum and maximum supply pressure requirements listed in Table 4 on page 13 with all gas fired appliances connected
to a common gas main firing at full capacity.
Note: A pressure drop of more than 1.5” W. C. (0.37 kPa) when the Main Burner ignites is an indication of an inadequate supply of gas and can lead to ignition failure, rough starts and/or rough operation. If a drop of more than 1.5” W. C. (0.37 kPa) in supply gas pressure occurs when the Main Burner ignites, ensure the supply gas lines and regulator(s) are properly sized and installed. See the requirements for Supply Gas Regulator and Supply Gas Line on page 13. See Supply Gas Line Installation on page 37 and Supply Gas Regulator Installation on page 38. Ensure all requirements and installation instructions are maintained.
Manifold Gas Pressure Adjustment
Fire and Explosion Hazard
Under no circumstances should the input exceed the rate shown on the water heater’s rating label.
Overfiring could result in fire or explosion.
Gas and carbon monoxide detectors are available.
Breathing Hazard - Carbon Monoxide Gas
Under no circumstances should the input exceed the rate shown on the water heater’s rating label.
Overfiring could result in damage to the water heater and sooting.
Gas and carbon monoxide detectors are available.
Breathing carbon monoxide can cause brain damage or death. Always read and understand instruction manual.
Ensure the "dynamic" supply gas pressure is above the minimum requirements in Table 4 on page 13 before any adjustments are made to the manifold gas pressure. Attempts to adjust manifold gas pressure during periods of low supply gas pressure could result in overfiring when the supply gas pressure returns to normal. See Supply Gas Pressure Adjustment on this page.
If necessary, adjust the manifold gas pressure as follows:
1.Follow the instructions for Initial Start Up on page 50 to connect manometers to the supply and manifold gas pressure taps and to start the water heater.
2.Remove the manifold gas pressure regulator cover screw, see Figure 56.
3.Using a small flat tip screw driver turn the adjustment screw clockwise to increase manifold gas pressure and counter clockwise to decrease manifold gas pressure.
Note: Turn the manifold gas pressure adjustment screw in small increments (no more than 1/4 turn) and allow the manifold gas pressure to stabilize for several minutes before making further adjustments.
4.Replace the gas pressure regulator cover screw.
5.Cycle the burner on and off several times to check operation.
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