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Need to replace a Solic 200 Triac (I think ) - poor connection on immersion element -ran v hot and has stopped diverting despite saying it is ...........
I believe it says BTA400800B VV PHL101 -but is hard to read. Does anyone know correct part ? seem to be several variations of BTA40800B type...
Rgds George

Hello George
Have you measured the resistance of the heater / thermostat to confirm its not open circuit.
The BTA40-800B should not have failed with the wires going high resistance.

Hi Alan , - installed at brother in laws , -worked fine initially then he complained it was getting very hot / and stopped working........
Removed it himself then found a burnt neutral wire on his immersion element. unsure of the time sequence ? you've made me think -did he remove it prior to repairing wire ??
Guess i need to bench test it ,,,,,,,,,,
George

Would it have got hot with high resistance ??
George

I have played about with them connected to a 100 watt tungsten bulb / small heater while testing.
It should not have got hot.
High resistance on the immersion heater neutral should not have upset it.
Earth fault on the element would.

Hmmm - was definitely a burnt connection on immersion N. Think i need to test it . Was fitted to 4kw system with a low house consumption so perhaps was diverting lots before N on immersion failed .....(not previously used to heat water as on oil boiler) . Unsure how hot is hot ?
George

Don't believe there is an earth fault ? but don't want to ask as he's given me the Solic 200
George

Testing on the work bench I just connect the current transformer onto an electric heater to simulate generation with the current transformer turned the other way round.

Maybe worth doing a light bulb test before replacing the triac. But it's not unheard of for a poor connection to kill electronic components - arcing across the bad connection can cause voltage spikes. Although triacs more usually fail short-circuit, i.e. immersion continuously on.

BTA40800B seems to come up consistently with the right one for me:
BT = triac series
A = insulated case
40 = 40amps, RD91 package
800 = 800V
B = 50mA sensitivity

seems to be a STmicroelectronics part.

UPDATE
Finally got around to replacing Triac today and yes it works again
Nice cheap repair -thankyou China components.....
Temporary install to replace my wireless version which i have broken boost switch on pcb and has problem of cutting out on overheat (but not overheat) at low diversion levels.....will get repair or pcb replacement.....
Thanks all for input.....