Specifications

COMMISSIONING
47
Gas Inlet Test Point Pressure
To check the gas inlet pressure:
1. Close any hot taps and ensure the burners are not operating.
2. Close the gas isolation valve at the gas
inlet to the water heater.
3. Locate the gas inlet test point on the gas
connection to the water heater.
 Remove the test point screw and
washer from the test point orifice.
 Connect the manometer.
4. Open the gas isolation valve fully at the
gas inlet to the water heater.
5. Observe the gas pressure reading on
the manometer.
If the manometer reading is between the minimum and maximum gas pressure ratings on the rating
label, no adjustment is required.
If the manometer reading is below the minimum gas pressure rating on the rating label, then either the
gas pipe to the water heater is undersized and needs to be rectified or adjustment is required at the gas
regulator.
If the manometer reading is above the maximum gas pressure ratings on the rating label, then
adjustment is required at the gas regulator.
6. Switch on the electrical supply at the power outlet to the water heater if it is not already switched on and
turn on a controller, if one is fitted, by pressing the on / off button.
7. Open a hot tap fully and ensure the burners are fully ignited.
It may be necessary to open a second tap.
8. Turn on all other gas burning appliances in the house which are on the same gas supply.
9. Observe the gas pressure reading on the manometer.
If the manometer reading is between the minimum and maximum gas pressure ratings on the rating
label, no adjustment is required.
If the manometer reading is below the minimum gas pressure rating on the rating label, then either the
gas pipe to the water heater is undersized and needs to be rectified or adjustment is required at the gas
regulator.
If the manometer reading is above the maximum gas pressure ratings on the rating label, then
adjustment is required at the gas regulator.
10. Turn off the other gas burning appliances in the house.
11. If an adjustment was made during Step 9, repeat this procedure from Step 5.
12. Close the hot tap(s).
13. Close the gas isolation valve at the inlet to the water heater.
14. Remove the manometer and refit and tighten the test point screw and washer.
15. Open the gas isolation valve fully at the gas inlet to the water heater.
16. Open a hot tap again so the burners ignite.
17. Test for gas leaks.
18. Close the hot tap.
GAS INLET
INLET TEST
POINT ORIFICE
TEST
POINT
SCREW
WASHER
MANOMETER
INLET GAS PRESSURE TEST
873, 874, 876 SERIES - CONTINUOUS FLOW GAS WATER HEATER