air con not responding until power reset

[andyh]

I come across calls every now and then to air conditioning systems (no particular make) that do not respond to any setting modes.
When i switch the supply isolator off for a few seconds then back on again the sytem responds and operates perfectly.
I assume this can be down to a temporary corrupted power supply/electrical spike that affects the pcb/s?

Has anyone experienced this type of fault and if so do you know why?

Many thanks Andy!

[Brian_UK]

Common problem I think Andy.

I put it down to Bill Gates having written the code for the on board software running the damn things

[NoNickName]

It's called watch dog. When it operates correctly, the watch dog resets the uP. If not, the software hangs forever.
I would perform a power line test analysis with an oscilloscope.

[slingblade]

I would perform a power line test analysis with an oscilloscope

Good idea.
As luck would have it, i have 3 of those in the boot of my car for just such an occasion.

[The Viking]

Hang on,

By turning the power off you will, on most systems, reset any and all fault-codes.

So before you turn the power off, check LEDs and controllers for indication of errors......


Just a thought.

[NoNickName]

Good idea.
As luck would have it, i have 3 of those in the boot of my car for just such an occasion.

It may look pompous, but I bought it from the ebay for 280 euro and it's really very useful to check fast events like spikes or to measure LRA.
I just returned a 120 ton compressor to the producer who claimed 470A LRA PWS, while really it pulls 630A