CHECKING THE GAS SUPPLY PRESSURE
Checking the Gas Supply Pressure
Gas pressure checks are done with flowing gas using a gas pressure gauge capable of reading pressure in inches of water column.
•Supply gas pressure checks are measured before the gas control valve/thermostat and as close to the water heater as possible.
•Manifold (main burner) gas pressure is measured at the pressure tap on the bottom of the gas control valve/thermostat. Use an Allen wrench to remove the plug then attach the gas gauge.
NOTE: Desired gas pressures will be noted on the gas valve label located on the gas control valve/ thermostat.
WHITE RODGERS GAS CONTROL | GAS PRESSURE LABEL |
VALVE/THERMOSTAT SHOWN |
|
GAS |
PRESSURE |
GAUGE |
CONNECTED AT |
PRESSURE TAP |
MANIFOLD GAS PRESSURE TEST
Figure 16
IF . . . | . . . THEN |
supply gas pressure is under desired pressure | • increase supply gas pressure regulator setting |
requirement | and, |
| • increase supply gas piping size. |
supply gas pressure is over desired pressure | • add gas pressure regulator. |
| • reduce setting on existing regulator. |
manifold gas pressure is more than | • ensure there is adequate supply gas pressure |
W.C. from values indicated on gas valve | • ensure the main burner orifice is the correct size |
| |
| for the water heater model being tested. |
| • if the above tests have been performed and the |
| results were correct replace the gas control valve. |
|
|
CHECKING FOR SUFFICIENT COMBUSTION AIR OR VENTING ISSUES
Combustion Air Test
The Installation Instructions and Use & Care Guide gives guidelines under “Air Requirements” and “Unconfined “ or “Confined Space” sections. If you want to test for a lack of air:
1.Turn on every appliance and fan that exhausts air from the utility room and/or house. Make sure all windows and doors are closed, as well as chimney dampers.
2.Open a hot water faucet so that the main burner will ignite
3.Remove the outer door of the water heater – not the inner door
4.Monitor the flame characteristics for several minutes
If the flame begins to “yellow” open a door or window, to the outdoors, to see if additional air corrects this back to blue. If it does, the room needs more air supply.
EXHAUST FAN |
VENT |
REVERSE FLOW |
OF VENT PRODUCTS |
Figure 17
18
