Mitsi Electric RP6AA Pump Fault

[gwilliamson]

Hi Chaps

Has anyone had this problem or similar before.

Went to an account a couple of weeks ago with a P5 fault which was put down to a faulty pump or sensor.

Went back today and changed the above and still have the P5 error. Spent some time on the phone with Mitsi technical and they believe it must be a faulty indoor pcb.

I have ordered a PCB and will return as soon as it arrives but they didnt really inspire me with confidence when arriving at there diagnosis!

Have any of you had similar problems and is there any obvious things i should check on this Mitsi Elec kit before i change the PCB.

I have not worked with Mitsi Elec much in the past, normally install for the dark side with MHI and Daikin.

Any advice would be much appreciated.

Thanks

Gareth

[Daikin=Overated]

Hi Chaps

Has anyone had this problem or similar before.

Went to an account a couple of weeks ago with a P5 fault which was put down to a faulty pump or sensor.

Went back today and changed the above and still have the P5 error. Spent some time on the phone with Mitsi technical and they believe it must be a faulty indoor pcb.

I have ordered a PCB and will return as soon as it arrives but they didnt really inspire me with confidence when arriving at there diagnosis!

Have any of you had similar problems and is there any obvious things i should check on this Mitsi Elec kit before i change the PCB.

I have not worked with Mitsi Elec much in the past, normally install for the dark side with MHI and Daikin.

Any advice would be much appreciated.

Thanks

Gareth

Check at the pump connections that your getting 240v volts, or if it's switched through a float switch or similar then check the mechanism and continuity. The only component that can really be at fault on the pcb is the switching relay so find and check the output doing the above whilst triggering the float switch by hand manually. Very Unlikley though not unheard of regarding Mitsi's diagnostics....how old was the system, and how bad was the drip tray?

Is the pump pumping water if when you determine that it works at all. Are the drains clear??

Well worth checking the dip switch settings too with Mitsi, as there have been a batch of defective sticky dip switches fitted to indoor/outdoor pcb's over the last 2 years causing intermittant faults where the tiny dip switch hasn't made contact. Get switch cleaning lubricant and whilst the system shut down (isolated) give each bank of switches a squirt of cleaner then gently rock the switch back and forth a couple of times with a flat head terminal driver. give this ago, let me know how you get on (applies to both indoor/outdoor unit dip switches).

[gwilliamson]

I would say 3 - 4 years old and the drip tray was disgusting. However cleaned all that out and checked all the pipe work.

The fault comes up instantly even though the drip tray is empty. Its an electronic sensor rather than a float.

Thanks

Gareth

[Daikin=Overated]

Is it a Mitsi inverter? If so check the dip switches as advised. Sounds like the drains could be blocked if the tray was that bad, if the pump can't pump, the float will trigger the alarm when the level raises in the tray and give you the fault.

I appreciate the fault remains and prompts immediately, if you check all the above and believe there to be no fault then this fault may simply need clearing?

[gwilliamson]

When you say clearing the fault how exactly would you do this?
Daft question i know but the Mitsu guy just asked me to switch off the indoor power supply for 20 seconds?

[coolhibby1875]

this fault could also be that the sensor in the drain gully is coated in slime or sludge and is not sensing the air across it this also will bring up a p5 fault

[Brian_UK]

As Coolhibby says, check the sensor.

Any scale or crud on the sensor tip should always be cleaned off as the sensor will no 'dry' and achieve the switch off temperature.

[Thermatech]

The drain sensor is often mounted on the pump bracket & so I suspect that you would have made sure it was clean when you fitted the new pump.
Do I understand correctly that you changed the pump & sensor together ?

Mitsubishi drain sensors normally are a heated temp sensor.
So when the drain water level is ok the sensor is in air & very hot which is measured at the circuit board.
When the water level is high the sensor is in the water & is therfore cold which the circuit board reads & stops on drain fault.

So the exact mounting possition of the sensor is important & both the temperature sensor & heater need to work correctly.

If you replaced the pump & sensor & you are sure they are both mounted at correct possition then it could be that the circuit board is the problem.

[gwilliamson]

Hi

Yep, Changed both the sensor and pump just to make sure.

Just wondering is there a set procedure for resetting the error in a Mitsi Elec remote or will switching off the supply to the indoor unit suffice?