Can anybody back my theory up?

[Coolie]

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

[frank]

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

[rbartlett]

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

cheers

richard

[Brian_UK]

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.

[Coolie]

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

[Brian_UK]

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

Is this where we all go - Told you so

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