4.13 Measuring gas pressure
4.13.1 Gas supply pressure
Confirm gas pressure upon installation.
▶ Shut off gas supply at installer supplied shutoff valve for
this water heater.
▶ Locate the inlet gas pressure test port (see Fig. 21).
▶ Loosen the screw inside test port fitting (do not remove)
and connect the manometer tube to the test port (see
Static Pressure Test
▶ Turn the gas supply back on.
▶ Record the static gas pressure reading in table 10.
Dynamic Pressure Test
▶ Turn ON the appliance.
▶ Access menu P1 Max. Power, see chapter 8.11.2.
Note: While in this mode the appliance will run constantly at
maximum power and allow maximum water flow.
For inlet gas pressure adjustment consider the following table:
Inlet gas pressure
Minimum inlet gas pressure under full operation
▶ Operate all other gas appliances (except heater) on the
same gas piping system at maximum output.
▶ Open all hot water taps to achieve a flow rate of at least 6
gallons per minute. (1 tub and 2 sinks should be sufficient).
If heater goes back to P2, open more hot water fixtures to
allow sufficient flow and access to P1.
▶ Record the lowest operating gas pressure reading in
▶ Turn OFF the appliance.
▶ Shut off gas supply.
▶ Disconnect the manometer tube from the test point.
▶ Tighten the screw inside test point fitting.
Gas pressures lower than 3.5" W.C. for Natural Gas may result
in reduced power output.
Greentherm T9800 SEO 160/199 | SECO 199 – 6 720 817 281 (2018/12)
Gas pressure test port
 Gas pressure measuring point
Static Gas Pressure Reading
Dynamic Gas Pressure
Table 10 Inlet gas pressure readings
Electrical power supply
▶ For safety reasons, disconnect the power supply cord to
the water heater before any service or testing is performed.
▶ For safety reasons install a proper waterproof outlet.
▶ This water heater must be electrically grounded in
accordance with the most recent edition of the National
Electrical Code. NFPA 70. In Canada, all electrical wiring to
the heater must be in accordance with local codes and the
Canadian Electrical Code, CSA C22.1 Part 1. Do not rely on
the gas or water piping to ground the metal parts of the