COMMISSIONING
40
GAS INLET PRESSURE
IMPORTANT – CHECK
the gas supply pressure at the inlet to the water heater
with the water heater and all other gas burning appliances in the premises
operating (burners alight).
The minimum gas supply pressure for Natural Gas is 1.13 kPa.
If this minimum cannot be achieved, it may indicate the meter or the gas line to
the water heater is undersized. It is important to ensure that an adequate gas
supply pressure is available to the water heater when other gas burning
appliances, on the same gas supply, are operating.
GAS SUPPLY PRESSURE TESTING
To check and adjust the gas supply pressure to the water heater:
1. Ensure all other gas appliances in the premises are operating (burners
alight).
2. Remove the access cover.
3. Close down the gas control (refer to “Close Down Procedure” on page 47)
and close the gas isolation valve to the water heater.
4. Remove the screw from the inlet pressure test point on the left hand side of
the gas control and attach the manometer hose to the test point (refer to the
gas control diagram on page 41 for location).
5. Open the gas isolation valve fully.
6. Light the water heater and ensure the burner is operating (refer to “Lighting
the Water Heater” on page 43).
7. Take the manometer reading (burner must be operating).
The supply pressure must be above the minimum rating.
8. Close down the gas control (refer to “Close Down Procedure” on page 47)
and close the gas isolation valve to the water heater.
9. Remove the manometer hose from the inlet pressure test point and replace
test point screw.
10. Open the gas isolation valve fully.
11. Check the gas inlet pressure test point for leaks.
12. If the gas inlet pressure is correct, then check the burner gas pressure of
the water heater. Refer to “Burner Gas Pressure Testing And Adjustment”
on page 41.
13. If the minimum gas pressure cannot be obtained, check the size of the gas
pipe to the water heater or if adjustment to the main gas supply regulator is
required, then contact your local Gas Authority.