Mitsubishi Electric PQHY-P72ZLMU-A Service Handbook page 259

[ IX Troubleshooting ]
1. Error Code
2134
Abnormal water temperature
2. Error definition and error detection method
1) If a water inlet pipe temperature (TH7) of 5°C[41ºF] or below OR 50°C[122ºF] or above is detected (first detection) during op-
eration, the heat source unit stops, goes into the 3-minute restart delay mode, and automatically restarts after three minutes.
2) If a water inlet pipe temperature (TH7) of 5°C[41ºF] or below OR 50°C[122ºF] or above is detected again (second detection)
within 30 minutes of the first stoppage of the heat source unit, the unit will make an abnormal stop, and the error code "2134"
appears on the LED.
3) If a water inlet pipe temperature (TH7) of 5°C[41ºF] or below OR 50°C[122ºF] or above is detected after 30 minutes of the first
stoppage of the heat source unit, this is considered as the first detection, and the sequence as described in section 1) above
is followed.
4) The period of 30 minutes after a stoppage of the heat source unit is considered a preliminary error, and a preliminary error
code appears on the LED display.
3. Cause, check method and remedy
(1) Heat source water circulation pump fault
(2) Cooling tower or heater problem
(3) Thermistor fault (TH7)
(4) Thermistor signal input circuit fault on the control
board
(5) Improper installation of thermistor (TH7)
HWE15150
Cause Check method and remedy
Operate the pump, and check for proper operation.
Check the cooling tower and heater, and correct any prob-
lems found.
Check thermistor resistance.
Check the sensor reading on the LED.
Check the sensor reading on the LED.
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