mitsi thermistor

[mcunliffe4]

could anyone help.

indoor unit PLFYP125 VAMA
outdoor unit PUHYP400 YMFB

On contoller fault codes 5109 and 5102
Suspect thermistor fault but could anyone please tell me which ones these correspond with,

Many thanks guys

[Thermatech]

This one can be a bit confusing.

All fault codes starting with 51 relate to temperature sensors open or closed circuit.
The remote controler should also indicate the address of the unit with the fault.

If the address is for the outdoor unit then 5102 is for TH2 suction temp sensor.

If the address is for an indoor unit then it is for TH22 which is a pipe temp sensor. You will need to find which indoor unit by looking at the address settings for each indoor unit in the system or if you are lucky the O&M manual should have the address settings of all units with the commissioning sheets.
Each indoor unit has 3 temp sensors one for return air & 2 coil temp sensors.

For the 5109 fault this will be one or both temp sensors for TH9a & TH9b on the outdoor unit
which are on the subcooler circuit & the CS refrigerant blend estimation sensing circuit.

The wiring diagram on the inverter pack lid will show which temp sensors you need to test & replace.

[mcunliffe4]

Thanks mate, i ordered up all 3 sensors for the fancoil and the TH9 sensor for the outdoor unit, no manuals or commisioning sheets on site so managed to trace location of particular units using the barrel switches, are these sensors difficult to replace. Am I right in thinking TH22 is the Liquid temp sensor ?

[Thermatech]

Th22 liquid pipe sensor on indoor unit might be a bit tricky on a cassette unit.
If you cant thread it through you might need to drop the drip tray for access.