Cooling water alarm

[srp]

For anyone thats interested, I've just put some information on the Corribee website - it's based on the alarm described in PBO about a year ago, but with a (very slightly!) more sophisticated circuit. Current drain is around 20mA. Total cost (including the flow switch) was around £20, and it has all the advantages of the original in that it gives a warning before the engine overheats (unlike an exhaust temp sensor). Here

 

[Flossdog]

Following an incident where my plastic exhaust water trap melted, I fitted a Vetus exhaust temp alarm but wanted to also fit a flow alarm. I bought the bits as described in PBO but didn't in the end fit them as I was concerned by the smaller bore of the flow sensor restricting water flow. What I did do was to buy a Halyard water intake sensor which operates when there is low pressure in the water intake due to weed blockage. Works a treat too and has already proved its worth.

 

[srp]

CPC also do a slightly larger bore flow switch - approximately 3/4" instead of 1/2" - which would be suitable for larger engines. I chose the 1/2" version as it more or less matched the water pump inlet on the Yanmar 1gm10. There's nothing in the switch to actually restrict the flow, as the float is contained in the tee piece. larger version

 

[Roger_D]

Looks very good, thanks....another winter project, but tell me, the reduction from 3/4 to 1/2 will restrict the flow a little, so are there flow switches of greater diameter? (presumably not as you would have done so) My memory tells me that there are reed swithes or such that clamp on to hoses...but I am not sure.