mitsubishi mr slim P6 error

[symon22]

hi chaps,
i have a re-occuring error code p6 on a mitsi mr slim unit .

have followed the mitsi fault code sheets and have found no fault.

the unit checks out fine in all modes of operation and works fine for a period of time then fails with the same problem.

have any of you any pointers ,or have come across this before,

any input would be greatful

thanks..

[p_p]

I have come across this before and allways found it to be refrigerant charge problem.

Regards

PP

[Thermatech]

Mr Slim A control R407c & R410a systems.
P6 = indoor coil frost protection in cooling or indoor coil overheat protection in heating.

Cooling
One of the 2 indoor coil sensors reads minus 15 deg C for 3 mins.
Heating
One of the indoor coil sensors reads over 70 deg C.

If you are sure the refrigerant charge is correct & system operation is correct then it could be a coil temperature sensor reading wrong temperature.
If you have one of those little monitor things which plug into the outdoor circuit board you can monitor the indoor coil temperature.
On later type remote controllers you can get all operating data like temp sensor data but you will need a service manual to do this.
Or you can measure the ohms resistance of the temp sensors & compare with the chart in the service manual.

[hishvac]

Having the p6 error code problem with a mr slim pu42ek21. any advice. pressure washed evap section . was plugged> topped off charge was 88 degrees in space with a 75 back.

[Thermatech]

I suspect that you have an R22 K control cooling only system.
On the old R22 K series Mr Slim systems sold in the UK P6 is coil frost fault in cooling mode & the indoor coil temperature sensor must be reading below +1 deg C.
So if you are sure indoor fan is working correctly & coil is clean most likely cause could be.
1/ indoor coil temp sensor fault
2/ short of gas
3/ part blockage of liquid line capillary

On the old UK models from early 1990's you could read the aprox indoor coil temp using the hard wired remote controller. In test mode the remote controller gave a code for the indoor coil temp & a chart in the service manual to convert.
As your unit is USA model & deg F I suspect it my be slightly different