Can somebody please try ID this electrical item and what the circuit does?

[habanerocat]

This part of the circuit may be in relation to refrigeration or cooling in general.
I've been asked to evaluate this circuit but I don't know what IL1 is.
I assume BS21 is a switch, switching possibly temperature probes.

But I'm confused in general. Can anybody help.

 

[habanerocat]

Did that circuit diagram upload correctly?
I'm seeing the wrong image.

 

[RRaghunath]

IL1 seems to be a Thermistor.


R Raghunath

 

[habanerocat]

Thanks, but I think it's a version of one of these....