header tank warning level

[tjk]

Hi Forum

I have just fitted a header tank as fitted to vw, skoda, seat .The cap is rated at 21.75 psi which seems to working well.

Two Questions -Is psi to high and how to wire up level warning. There is no float in tank but to thin prongs that go about 3/4s to bottom. My quest is that when the water level is above these prongs it completes the circuit. I would have to use a relay as it would be live when at proper level, But was this designed to run full 12 volts or a smaller voltage. I may well be way off the markany ideas please.

TJK

[Guest]

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If it makes the circuit when full, you will need to "interpose" it with a relay. So using a normaly closed contact of the relay to you buzzer/light, the tank switch wired to operate the relay coil, when the tank is full, circuit made, this will energise the coil thus opening the relay contact!

Put an inline fuse for the relay contact and use a fused relay (which i think fuses the coil)

The switch should take the full 12v!

Jason

[tjk]

imported post

Hi Jason

Many thanks for your reply

TJK

[marshman]

imported post

Hi,

I'm not 100% certain but if it is not a float swtch but two closely spaced probes I think you may have a problem getting it to switch a relay. The problem couldl be that there may not be enough current flowing to energise the relay coil. I suspect that because it is from a modern car there were some electronics involved. If this proves to be the case then you will need a transistor to amplify the current before you can use it to switch anything. It may be worth trying with a relay first but I would not be hopeful of success.

Roger

[singapore stag]

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Further to Roger's suggestion,..if this is the kind of sensor switch on the header then electronics are involved,

[tjk]

imported post

Hi

Yes I see your point . the sensor is just two long prongs with no insulation on them, not as in the picture

TJK