• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

can anyone help me work out this circuit diagram

Not open for further replies.


New Member
Hi all,

I have bought a used kerosene jet wash with the mains switch missing, but there are 2 black wires marked S1 and S2 that are part of a 5 core cable that goes to the mains switch, I'm no electrician but S looks like it is for switch?.

I have drawn this diagram on a drawing program that I have never used before and as far as I am aware it is an identical copy of the boards.

Please tell me if you see anything you thing wrong and i'll look into it

I think that S1 & S2 are some kind of under/over pressure cut out but I need to know where they should be connected too?

what I do know is that relay 2 is for the hot water and pulls the burner in and seems to work fine and is 240v

Relay 3 is 24v ac and comes in when the trigger is opened and water is released

The wires for TC1 & TC2 are tiny aprox 0.25 dia so i'm sure it would have to be a 24v circuit

Once again sorry for the crude drawing and the lack of knowledge

I hope this looks nice and easy to you technical people, just need to know where S1 & S2 go and what this circuit is for

Cheers guys



New Member
This circuit controls the water flow according to pressure and temp. I would think TC1 TC2 is temp control and S1 S2 goes to a temp sensor.
Last edited:


New Member
Hi, thanks for the reply, I guessed it was either over temp or pressure cut out but S1 & S2 come from a 5 core cable with a cable gland on it as if it goes to the mains switch!!! there is nothing close that they can connect to, they had ring terminals on the ends too as if they fitted to a switch or terminal, there are 2 other cables with glans on one is the armour cable mains in and the other goes dirct to the pump so it can run without the burner.

There is a switch that controls the burner right next to where the start stop switch would be, this switch is 24v ac HSC1 HSC2 single pole double throw BUT part of the switch body is missing for what would be the off position!!

There would have to be a power supply to S1 because it is switched by relay 1 what I cant work out is where it comes from I have lots of pics of the machine and the components and wires if that will help anyone

AHHHHHHHH much head f**k my brain hurts :confused:
Not open for further replies.

Latest threads

EE World Online Articles