Takagi 110U Indoor (T-KJr2U-IN) Installation Manual And Owner's Manual page 18

GAS SUPPLY AND GAS PIPE SIZING
-General-
Check that the type of gas matches the rating plate first.
Ensure that any and all gas regulators used are operating properly and
providing gas pressures within the specified range shown below. Excess gas
inlet pressure may cause serious accidents.
CAUTION
The manufacturer is not liable for any property and/or personal
damage resulting from gas conversions
Gas type Inlet gas pressure
NOTICE