Can anybody back my theory up?

I got sent on a call out today to the British Red Cross, to deal with a unit blowing out "Black Soot". When I arrived I found a Toshiba Split system with the indoor wall mounted unit iced up.
Upon investigating, I found that the fan scroll was extremely, and I mean extremely, clogged. My innitial theory was that the deminished air flow across the evaporator caused the ice build up. That was untill I looked at the outdoor unit. This was only very briefly as I had to leave to make it to evening class for my HNC. I found that even though the indoor unit setpoint was 29 degc(to melt the ice) the comp was still running. Even when I had it in fan only mode, the comp was still running.
Now it is a very old system and as far as I'm aware does not have an emergency run mode. I also thought it might have been the return air thermistor but ruled it out when the comp was running in fan mode! I am going back tomorrow to fully investigate the poblem. Now, after thinking a bit about the problem the only thing I can think of is that the indoor pcb is knackered, therefore sending the signal to the comp to run when it shouldn't!

• Firstly does anybody know much about toshiba, your help will be greatly appreciated
• Does anybody have a number for their tech dept here in the uk.
• Does anybody have any suggestions

2 points come to mind but the first is probably the one that is causing the trouble - sounds like the contactor is welded.

The second one is to check the indoor coil sensor

http://www.toshiba-aircon.co.uk/html...r_support.html

cheers

richard

I'll back up Franks comment, there is a small power relay on the indoor board, about the size of a matchbox, that welds itself in the ON position. Disconnect the power wire and watch the compressor stop.

Turned out to be the contactor after all!
Still had continuity across the switch with the unit isolated.

Quote:

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Originally Posted by Coolie

Turned out to be the contactor after all!
Still had continuity across the switch with the unit isolated.

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Is this where we all go - Told you so ;) :D

Glad that you sorted the problem Coolie especially on a friday.