Troubleshooting; Error Codes - Takagi T-M1 Installation Manual And Owner's Manual

Common Trouble Shooting
The T-M1 can burn gas at a maximum input
rate of 235,000 BTUH. This puts a limit on the
possible output temperature
capabilities. If the water doesn't seem hot
enough, compare the flow and temperature
that is being attained to the T-M1 flow vs.
temperature chart (See flow chart on the last
page of this manual). If the unit is not
performing according to the chart, first check
that the gas supply pipe is sized properly and
that the gas pressure is within the required
range. If the gas line is sized properly, check
the plumbing for mixing valves, thermostatic
valves, anti-scald devices, single handled
faucets with built in temperature or pressure
compensators valves and hot and cold crossed
connections. If the unit is performing in
accordance with the flow chart, it may be
undersized for the application. If the unit is
performing according to the chart, the output
temperature can be adjusted using the TM-
RE10 or the dipswitches on the unit.
It Takes Too Long to Get Hot Water
The T-M1 takes three seconds to ignite and
three more seconds to heat the incoming
ground water up to the set temperature. The
time it takes to deliver hot water from the T-M1
to your fixtures depends on the length of piping
between the two. The longer the distance, the
more time it will take.
receive hot water to your fixtures quicker, you
may want to consider a hot water recirculation
system.
Error Symptom
031 Wrong Gas Type
Insufficient Gas
101
Supply
111 Ignition failed
121 Loss Flame
141 Hi-Limit Switch Trip
211 Vent Pipe
Output Thermistor
311
Fail
Inlet Thermistor
321
Fail
and flow
If you would like to
Error Symptom
331 Mixing Thermistor Fail
Abnormal
391
Thermocouple
441 Flow Sensor
Abnormal Main Gas
510
Abnormal Two-Way
541
611 Abnormal Fan Motor
Abnormal Output Adjust
651
661 Abnormal Bypass Valve
The T-M1 Will Not Initiate
First check the flow rate through the unit. If the
flow is less than .75 GPM, the unit will not
initiate. Check the filter for any debris or
damage. If you have installed a combination
system (a T-M1 doing both domestic hot water
and space heating), completely isolate the
heating system temporarily to ensure flow is
not backfeeding through your heating system
to supply the domestic water (by-passing the
T-M1).
If neither of those remedies start the unit, press
the lower green button marked "test (off)" on
the GFCI inside the unit. If the red light above it
does not come on, there is a problem with the
electrical supply to the unit. If that red light
does come on, hit the "reset (on)" button and
open a hot water faucet to re-try the unit. If the
problem persists contact Takagi for instructions
All Takagi units are self diagnostic for safety
and convenience when trouble shooting. If
there is a problem with the installation or the
unit, it will display a numerical error code on
the TM-RE10 (if installed) or at the bottom left
corner of the computer board to communicate
the source of the problem. Consult the
following chart for the cause of an error code:
The T-M1 consists of five major control
operations: Temperature control, Gas control,
Water control, Burner Control, and Main
computer control
Error
701
711
721
741
Valve
751
Valve
761
991
Valve
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ERROR CODES

.
Symptom
Abnormal Computer Board
Abnormal Gas Solenoid
Valve
Computer Pre-post Check
Problem
Main remote control
Trouble
Temperature Remote
control Trouble
Multi-system Controller
Abnormal Burning