Takagi T-K3 - Page 33

T-K3 Service Manual
Ver. 1.05
33
CONFI DENTIAL
Checkpoint
1
2
3 Check that the f ilter on the cold water inlet is clean.
4
1
1
2 Check if there is any blockage of the exhaust pipe.
3 Check the manifold pressure in the unit.
-Fault of flow adjustment valve
Checkpoint
1 Check whether the filter in cold water inlet is cleaned.
2 Check whether the gas supply pressure is adequate.
3
4 Fault of PCB in the T-K3.
① No volta
g
e to
g
as solenoid valve
(
SV 2
)
.
Normal: DC78
～
100V between COM
(
blue
)
& #53
(
oran
g
e
)
②
Normal: DC78
～
100V between COM
(
blue
)
& #73
(
red
)
5 Gas solen oid valve
(
SV 2
)
fault
① Disconnected wirin
g
to
g
as solenoid valve
(
SV 2
)
Normal: 1.3
～
1.9k
Ω
between COM
(
blue
)
& #53
(
oran
g
e
)
②
Normal: 0.9
～
1.7k
Ω
between COM
(
blue
)
& #73
(
red
)
6 PCB fault
①
No voltage to flow adjustment valve
Normal: DC7
～
16V between
(
red-black
)
7 Flow adjustment valve fault
Normal: 0.09
～
0.2k
Ω
between
(
red-black
)
・
The fan motor is still
spinning after
operation has
stopped
Nature of Fault Diagnosis
・
The hot water turns
cold and stays cold
Check whether the flow rate enough to keep the T-K3
running.
Check if ther e is a r ecirculation syste m installe d an d check
also if the recirculation line has enough check valves.
Check that the fixtures are free from debris and obstructions.
C
No voltage to gas solenoid valve (SV
3 ).
・
Abnormal sounds
come from the unit
Check if there is any blockage on the air inlet of the
unit.
Nature of
Fault
Malfunction description Cancellation method
This is normal. After operation has stopped, the fan
motor keeps its running from 5 to 50 sec. in order to re-
ignite quickly, as well as purge all the exhaust gas out
of the flue.
-Fault of gas solenoid valves (SV
3 & SV
2
)
during stage changes
・
Fluctuation
of hot water
temperature.
Diagnosis
Check for cross connections between cold water lines and hot
water lines.
C
Disconnected wirin
g
to
g
as solenoid valve
(
SV
3
)
J1
J1