Takagi 100 Series, Service Handbook

Page: 7 / 80

On-Demand Water Heater Service Handbook for 240, 340 & 540 Condensing Models • 7
TR
OUBLE
SHOO
TING
Remote Controller:
If you are using a remote controller,
the remote’s power button must be
turned on. Press the power button on
the remote until the amber Stand-By
LED is lit.
High Altitude:
If the heater is installed at an altitude of
over 2,000 feet, it may cause a lack of air
and incomplete combustion. See Dip
Switch Settings, page 23.
Long Vent Run
The length of your vent run may
require changes to your DIP switch
settings. See Dip Switch Settings, page
23. Also, see the installation manual
for venting requirements.
Hard Water:
What is the hardness of the water?
A means for reducing scale is always
recommended, but one must be installed
if water hardness levels exceed 7 grains
per gallon (120 ppm) for single family
domestic applications or 4 grains per
gallon (70 ppm) for all other applications.
If a means for conditioning hard water is
not installed, existing installations may
gradually accumulate scale buildup on the
heat exchanger and a leak could result.
(Descaling instructions are listed on page
38.) Heat exchanger leaks due to hard
water scale are not covered under the
warranty.
Water with higher concentrations
of dissolved minerals like calcium or
magnesium is considered to be “hard”
water. The higher the “hardness” of the
water, the more frequently the water
heater will need regular maintenance to
ensure trouble free operation at the best
possible efficiency.
New Installations:
If a newly installed water heater won’t
operate at all or operates erratically,
check for the following:
◦
Reversed hot and cold
plumbing connections. The
water heater must sense
water flow to initialize
operations. Water flowing
through the heater
backwards will not activate
the flow sensor.
◦
A dirty inlet filter. A dirty
inlet filter can either prevent
water from flowing through
the water heater entirely, or
create turbulence that can
prevent the flow sensor from
measuring the water flow.
◦
Misconfiguration of the Easy-
Link system (if applicable).
◦
Gas line that has not been
purged correctly.
External Problem:
1. Test whether the problem is within
the unit or external to the unit
(i.e., in the plumbing system) by
attempting to run hot water locally
through the isolation valve. Ensure
that the hot water shutoff is closed
while running water through the
hot isolation valve drain port. See
Figure 2, page 8.
2. Does the heater ignite and
continue to run properly? If it runs
properly through the hot isolation
valve, the plumbing system is at
fault. If the heater shuts down
with an error code or no operation
occurs, the problem is with the
water heater. NOTICE: If no error
code is displayed, you can use
Diagnostic Mode to review stored
error codes. See page 45.
Preliminary
Checklist
To get started, review the following
topics. You may also refer to “General
Issues,” if necessary.
Gas/Water/Electric:
•
Verify that the correct gas type
is being used. Check the supply
gas, the gas type dip switch, and
the gas type shown on the rating
plate. All three must agree in
terms of gas type, and your water
heater model must be designed
for use with that type of gas
(natural gas or LP).
•
The gas supply valve should
be fully open and the gas line
purged.
•
The water supply valve should be
fully open.
•
The unit must be connected to a
120 VAC 60 Hz power supply.
•
There is a power switch inside
the heater, located directly above
the control board, that must be
turned on before the heater can
operate.
TROUBLESHOOTING NORMAL OPERATION /