Measuring Inlet Gas Pressure; Water Connections - Takagi AT-KJr3U-IN Installation Manual And Owner's Manual

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 to the OFF position.
WARNING
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.
Shut off the manual gas valve on the gas supply line.
1.
Remove the screw for the pressure port located on the gas inlet of
2.
the water heater shown in the diagram on the right.
Connect the manometer to the pressure port.
3.
Re-open the manual gas valve. Verify that there are no gas leaks.
4.
With all gas burning equipment off, take a reading of the static gas
5.
pressure.
Measure gas supply pressure at maximum heater operation: Open
6.
up water faucets to create maximum flow. Press and hold the
MAX button on the computer board. Take a reading of the supply
dynamic gas pressure with all gas burning equipment running at
maximum rate.
The static and dynamic pressures should be within the ranges
7.
specified on the heater's rating plate and the table on p. 26.
The difference of static to dynamic pressure should not exceed
8.
1.5" W.C. Pressure drops that exceed 1.5" W.C. can indicate
restricted gas flow, undersized gas lines, and/or undersized supply regulators.
• Do not use this water heater if any part has been submersed under water. Do not attempt
to repair the unit. It must be replaced. Failure to follow these instructions could lead to
property damage, personal injury, or loss of life.
WARNING
NOTICE
• Do not reverse the hot outlet and cold inlet connections to the water heater.
This will not activate the water heater properly.
All pipes, pipe fittings, valves and other components, including soldering materials, must be suitable for
potable water systems.
1. A manual shutoff valve must be installed on the cold water inlet to the water heater between the
main water supply line and the water heater.
2. In addition, a manual shutoff valve is also recommended on the hot water outlet of the unit.
Isolation valves are recommended as shown in the picture at right.
3. If the water heater is installed within, or subjected to, a closed
loop water system, a thermal expansion tank must be installed to
handle thermal expansion.
4. Before installing the water heater, flush the
water line to remove all debris, and after
installation is complete, purge the air from
the line. Failure to do so may cause damage
to the water heater.
5. There is a wire mesh filter within the cold
inlet to trap debris from entering your heater.
This will need to be cleaned periodically to
maintain optimum flow. (Refer to p. 46.)

-Measuring inlet gas pressure-

WATER CONNECTIONS

As Close as
Pressure relief valve
28
Page
Installation Manual
Possible
Hot
outlet
Installation
Pressure port
Gas
inlet
Cold
inlet