John Wood Takagi - 240H-340H-540H - Manual (Page 22)

22
Page
-Measuring inlet gas pressure-
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.
WATER CONNECTIONS
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. If the
water heater is installed within, or subjected to, a closed loop water system, a thermal expansion tank
must be installed.
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.
• Do not use this water heater if any part has been submersed under water.
Immediately call a licensed professional to inspect the water heater to replace
any damaged parts.
• Do not reverse the hot outlet and cold inlet connections to the water heater.
This will not properly activate the water heater.
CAUTION
Installation
Installation Manual
1. Shut off the manual gas valve on the gas supply line.
2. Remove the screw for the pressure port located on the gas
inlet of the water heater shown in the diagram on 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 and minimum burn, the manometer should read
from 1.24 to 2.61 kPa (5.0” to 10.5” W.C.) for Natural gas,
from 1.99 to 3.48 kPa (8.0” to 14.0” W.C.) for Propane.
3. 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 heater.
4. 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. 41.)
Cold
inlet
Hot
outlet
Gas inlet
As Close as
Possible
Pressure Relief Valve
Pressure port