John Wood Takagi - 910 - Manual (Page 11)

11
Gas Supply And Gas Pipe Sizing
TO TURN OFF GAS
TO APPLIANCE
Turn off all electric power to the water heater if service
is to be performed.
Turn the manual gas valve located on the outside of
the unit clockwise 3 to the off position. 1.
2.
WARNING
Conversion of this unit from natural gas
to propane or vise versa will void all war-
ranty. Contact your local distributor to get
the correct unit for your gas type. The
manufacturer is not liable for any property
and/or personal damage resulting from gas
conversions.
*Check that the type of gas matches the rating plate first.
1. The minimum and maximum inlet gas pressures are:
Gas type Inlet gas pressure
Natural Gas Min.: 5.0" WC – Max.: 10.5" WC
Propane Gas Min.: 8.0" WC – Max.: 14.0" WC
2. Gas pressure below this specified range for the 910
and/or insufficient gas volume will adversely affect per-
formance. These pressures are measured when the 910
is in full operation.
3. Inlet gas pressure must not exceed the above maximum
values; gas pressure above the specified range will
cause dangerous operating conditions and damage to
the unit. Ensure that any and all gas regulators used
are operating properly and are providing gas pressures
within the specified range shown above.
4. Until testing of the main gas line supply pressure is com-
pleted, ensure the gas line to the 910 is disconnected to
avoid any damage to the water heater.
Measuring Inlet Gas Pressure
The 910 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.
Shut off the manual gas
valve on the supply gas
line.
Open a faucet. The unit
should turn on and the
gas in the gas pipe line
should purge. Leave the
faucet on to keep the
unit running until the unit
shut down due to lack of gas supply. Then shut the faucet
off.
Remove the screw for the pressure port located on the
gas inlet of the 910 shown in the diagram to the right.
Connect the manometer to the pressure port.
Re-open the manual gas valve. Check to see that there
are no gas leaks. 1.
2.
3.
4.
5.
Open some of the fixtures that use the highest flow rate
to turn on the 910.
Check the inlet gas pressure. When the 910 is on a
maximum burn, the manometer should read from 5.0”
to 10.5” WC for Natural gas, from 8.0” to 14.0” WC for
Liquid Propane.
Size the gas pipe appropriately to supply
the necessary volume of gas required for
the 910 models (380,000 BTU/h for both
Natural Gas and Liquid Propane) using
CSA B149.1 or local codes. Otherwise, flow
capabilities and output temperatures will be
limited.
Install a manual gas shut-off valve between the 910 and
the gas supply line.
When the gas connections are completed, it is necessary
to perform a gas leak test either by applying soapy water
to all gas fittings and observing for bubbles or by using a
gas leak detection device.
Always purge the gas line of any debris and/or water
before connecting to the gas inlet.
6.
7.
1.
2.
3.