Takagi T-M50 Installation Manual And Owner's Manual page 18

1. Turn off all electric power to the water heater if service is to be performed.
2. Turn the manual gas valve located on the outside of the unit clockwise  to
the off position.
The water heater cannot perform properly without sufficient inlet gas pressure. Below are
instructions on how to check the inlet gas pressure. THIS IS ONLY TO BE DONE BY A
LICENSED PROFESSIONAL.
1. Shut off the manual gas valve on the supply gas line.
2. Remove the screw for the pressure port located
on the gas inlet of the water heater shown in the
diagram to the right.
3. Connect the manometer to the pressure port.
4. Re-open the manual gas valve. Check to see that
there are no gas leaks. Open some of the
fixtures that use the highest flow rate to turn on
the water heater.
5. Check the inlet gas pressure. When the water
heater is on maximum burn, the manometer
should read from 5.0" to 10.5" WC for Natural
gas, from 8.0" to 14.0" WC for Propane.
-Measuring inlet gas pressure-
- 18 -