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frank
30-03-2014, 08:33 PM
Guy's
I've got a Tosh Rav...about 6kW...R410a....can't recall exact model at the mo, which keeps on shutting down after approx 5 minutes.
I've traced the fault to the compresser not being happy as it is ramped up to 266hz.!!!!
Anyone know what the maximum hz should be?
At 223 hz the amp draw is 8.4 so it's not over current
Discharge target is 100C but it is only around 69C when it shuts down
marc5180
30-03-2014, 09:20 PM
Guy's
I've got a Tosh Rav...about 6kW...R410a....can't recall exact model at the mo, which keeps on shutting down after approx 5 minutes.
I've traced the fault to the compresser not being happy as it is ramped up to 266hz.!!!!
Anyone know what the maximum hz should be?
At 223 hz the amp draw is 8.4 so it's not over current
Discharge target is 100C but it is only around 69C when it shuts down

Hi Frank, are you sure that's right, 266hz seems unusually high.
I know it's a different manufacturer but city multis only ramp up to a max 113hz.

Could it be a low discharge superheat fault?

I'll look in my manuals later to see if I've got any info on the max compressor hz if no one else has posted.
frank
30-03-2014, 09:34 PM
Exactly Marc...Daikin only go to 189 hz or so.

My hz clamp doesn't lie... :)��
marc5180
30-03-2014, 09:56 PM
Just out of interest, what's the discharge at and what mode was it running in?
frank
31-03-2014, 09:03 AM
Heating mode, discharge temp at cut out was +68C...target is 100C according to the service manual

Full model number is RAV-SM802AT-E
marc5180
31-03-2014, 10:26 AM
As you probably know, It doesn't seem to show the Hz for some reason but rather the rps of the compressor. At 8.4 amps it's roughly 75 rps but in heating mode this can go up to 120rps which consumes 14amps so going off them figures suggest it's only running about 60%.

It does say 'the compressor Hz measured with a clamp meter is 2 times the revolutions (rps) of the compressor'

Even so, that's still a long way off 223Hz.
frank
31-03-2014, 12:18 PM
Yep..got that already. On the graph for the compressor, it shows maximum 120rps @ 14A, so taking Hz to be (rps x 2) it looks like the compressor maximum rpm = 7200. At 266hz, (133rps) it seems to be pushing the compressor outside of it's envelope (7980 rpm) at 60% capacity :p

The sound it makes seems to confirm this.

Spoke to Tosh Tech this morning, he seems to agree that it is the inverter pcb at fault but suggests we megger the compressor first to make sure that it is healthy.