36 | Electrical connections
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.28).
▶ 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 18.
Dynamic Pressure Test
▶ Turn ON the appliance.
▶ Access menu P1 Max. Power, see section 6.6.
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
Table 17 Minimum inlet gas pressure under full operation
1) For lower inlet gas pressure refer to section 4.6.3.
▶ 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 to keep the water heater in P1.
▶ Record the lowest operating gas pressure reading in
▶ Disconnect the manometer tube from the test point.
▶ Tighten the screw inside test point fitting.
Depending on the vent length, gas pressures below 5" W.C. for
Natural Gas or 8" W.C. for LPG may result in reduced power
output or possible error codes and must be corrected. See Gas
Connections, chapter 4.8, page 28.
6 720 816 815 (2016/10)
Gas pressure test port
 Gas pressure measuring port
Static Gas Pressure Reading
Dynamic Gas Pressure
Table 18 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
▶ 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
▶ Modification of or tampering with the
power supply cord is prohibited.
▶ Use of extension cords is prohibited.
The water heater requires an electrical power supply from a
120VAC / 60Hz properly rated receptacle and must be
The water heater is wired as shown in the wiring diagram
(chapter 10, Fig. 51).
Greentherm 9800 SE 160/199 | SEC 199