Rittal Switch Board A/C

[Bunya nut]

Having problems with a Rittal SK 3305140 Switchboard A/C - 3 phase, basic controller - 2005. When powered up, the green light will flash (on 1 second/off 1 second)continually. Sometimes the evap fan will start up and run for a bit, sometimes even the compressor and cond fan run for a very short time. But that green light if it doesn't flash straight away, it'll start soon after a motor starts and then nothing will be allowed to run.
We've changed the pc board, electrically tested every motor and safety, thermistors measure about 8 k ohm each, run the compressor D.O.L. and even taken fans from other working units - but that green light continues to flash. We've also tried the new pcb in another working unit and it runs fine.
Any inside info on Rittal fault codes etc would be great, as there is very limited support where I am.

[r.bartlett]

We are the Southern UK Rittal appointed service agents

The green flashing light means 'door open' but obviously that's not the case here..It is possible that it's phase rotation -have you tried swapping two of the phases?

I have had one with the green light flashing but this was a drain sensor fault (roof mounted unit) so again this isn't appropiate

I did have one of these units which had a similar fault (although it was the red and green led on) the previous company had tried new controller,pcb, sensors so they gave up and disappeared..

Turned out to be the controller cable. They used to use a 1m cable for all the cabinets and occasionally the spare would dangle down and the condenser fan would slice it and the unit would not respond.

The basic controller is pretty rubbish as far as diagnosis goes..

http://www.rittal.de/downloads/Bedie...02/3302_gb.pdf

[Bunya nut]

Thanks for the link, will come in handy for sure. Tried phase reversal, checked all leads for continuity and had a closer look at the door limit switch area (none fitted) even swapped wiring lume with a working unit... am still at a loss with the unit.
These machines can be so touchy at times. Going to have another go at it later next week. Any other sugestions welcome. Thanks r.bartlett.

[chemi-cool]

I would simply install a different controller, there is nothing complicated here, any controller with two sensors and a digital input will do the job.
If you are not sure which controller to use, take with you the relevant page from the manual Mr. B have uploaded and show it to your supplier.

[Ken W]

Sorry to jump in on your post but I have a problem in that there is no lights at all on the basic controller.

I have swapped two phases and replace the basic controller.

Do you think it is the control board or could it be the cable? The cable appears to be in tact and I can see one red LED lit on the control board.

Thanks for any advice