air conditioner high-low voltage error

dodo41 · Apr 3, 2020

Hello friends. My air conditioner gives E6 error. It gives High / Low voltage error in the user manual. But when I measure the incoming energy, it's 220V. reading. I am uploading a few photos below. There is no energy in cable number 5 in the first picture. Does it have to be? The air conditioner comes from the outdoor unit to the indoor unit cable. I see it feeding the Out Fan in the air conditioner indoor unit. However, there is no energy due to the error, or is the problem arising from this?
I upload the photo of the card and cable distribution picture inside the air conditioner. Does anyone have an idea? For example, everything is normal but the circuit measuring the voltage is defective. Can we bridge this?
I measured the output of the transformer inside the air conditioner, and I did not come across a problem.

dodo41 · Apr 10, 2020

Hope it works

marconi · Apr 10, 2020

Remember the trim pot does turn a complete circle!
Please measure V1, V2 and V3 as you did earlier.
V2 should be about 9V or 0.75 x V1.
Carefully turn the trim pot until V3 is lowest voltage - I think that will be about 9V or 0.75 x V1 that is V2.
If air con does not start then try increase V3 little by little until you reach V3 = V1

dodo41 · Apr 10, 2020

Hello Again Marconi.
As soon as I changed the trimpot, my air conditioner worked.
I watched it for about 5 minutes and it didn't fail.
I still measured the V3 Value and the Value is 3.64V.
Should I continue to operate in this way?
I wonder if the error will recur.

westward10 · Apr 10, 2020

This has been an incredible thread and Marconi's knowledge and patience to hopefully have solved this with someone who is 2.5k miles away is amazing. Marconi you are a star I think we were all on edge of our seats at the end.

Mike Johnson · Apr 10, 2020

Will Marconi get an extra Esteemed if we give him enough Winner or like's, he deserves some kind of recognition.

marconi · Apr 10, 2020

dodo41: Thank you for your news. I'd like to know what V1 and V2 are please and your mains voltage at the time you measured these voltages.

From now on we will have to see what happens to decide whether to increase V3 or reduce V3.

Your air conditioning equipment has a mains voltage from 198V - 242V. The circuit we found faulty is creating a voltage V3 which is proportional to the mains voltage in your home. For a mains voltage of 220V ac then V3 is as you measured it = 3.64V. If the mains voltage was 240V I suppose that V3 will be 240/220 x 3.64 = 3.97V
If the mains voltage was 200V I calculate V3 to be 200/220 x 3.64 = 3.31V

For the upper mains voltage limit 242V, V3max would be 242/220 x 3.64 = 4V and for the lower limit 198V, V3min is 3.276V

Thus V3 must stay in the range 3.276 to 4 - not a very big interval - for the microcontroller to recognise the mains voltage as within the acceptable band.

At the moment 3.64V is 0.364V above the lower threshold and 0.36V below the upper threshold, or in other words mid interval.

I suppose your hom'es mains voltage is like the UK's - generally the upper level does not change much but on days of heavy network load the voltage will drop a few volts. If anything I think you may have to adjust the trim pot to increase V3 on days of low network voltage - but only time will tell. You knwo how to do it now and of course do measure the mains voltage, V1, V2 and V3 so you know what is happening require an adjustment.

If this is not clear tell me but now I must take Mabel our dog for a walk because she waiting.