Recommend me...............

[Graham_Wright]

.................. a water flow sensor.
I wish to detect flow in the sea water feed to the engine heat exchanger.
There are many such systems on offer on ebay but a simple moving/not moving switch would suit me better than an impulse generator.
Any suggestions please?

 

[Buck Turgidson]

What's wrong with looking at your exhaust like everyone else?

 

[Keith-i]

Aqualarm

 

[johnalison]

What's wrong with looking at your exhaust like everyone else?

Fine when the boat is stationary, and should be part of everyone's routine, but not so easy when under way. On my boat the exhaust comes out on the starboard quarter, which means that when on port tack it is at or below the surface. It can be very hard to judge the output when motor-sailing on port tack, when even the sound tends to get muffled, and I can see the OP's need for something better than relying on observation.

 

[Graham_Wright]

What's wrong with looking at your exhaust like everyone else?

Centre cockpit and the transom is an interesting trip in weather!
Apart from that, I doubt anyone spends all their time at sea checking the exhaust outlet.
I would like something that warns against blockages (and forgetfulness )

 

[Graham_Wright]

Aqualarm

I prefer to pay less than $100. One of those is actually a flap actuated switch (magnetic or proximity) which is what I am looking for.
I'm sure the Chinese have copied it.

 

[Alex_Blackwood]

.................. a water flow sensor.
I wish to detect flow in the sea water feed to the engine heat exchanger.
There are many such systems on offer on ebay but a simple moving/not moving switch would suit me better than an impulse generator.
Any suggestions please?

https://www.watercoolinguk.co.uk/cat/Flow-Indicators_1148.html

 

[Refueler]

Just a thought .... would a temp alarm set at a lowish temp on the exhaust be better ? Water flow may be fine - but what if HE is kaput / cooling not actioning for engine ?

 

[migs]

I used one of these:

https://cpc.farnell.com/gentech-international/fs-02/flow-switch-300v-0-5amps/dp/SN35507?ost=sn35507

I put Tru Design hose barbs on each end and fitted the flow switch in line with the water flow. It’s been working very well for the last five years, and has saved my bacon on more than one occasion...

The flow switch provides a simple contact closure that you could use to drive a buzzer, but I made a standalone battery-powered electronic version to avoid running any new boat wiring. The rechargeable battery lasts about a year and the device plays a tune when the flow starts (to check the unit is working) and a different one when the flow stops.

 

[Minchsailor]

NASA cooling water temperature alarm - got me out of trouble after I had cleaned the filter and failed to open the seacock..........

 

[ChromeDome]

Aqualarm

+1
Actually 2 - I have two engines

 

[Graham_Wright]

Just a thought .... would a temp alarm set at a lowish temp on the exhaust be better ? Water flow may be fine - but what if HE is kaput / cooling not actioning for engine ?

Probably too late to save the Jabsco impeller. As a deaf old git and despite checklists everywhere, it is not unknown for me to forget to open the sea valve.

 

[Graham_Wright]

I used one of these:

https://cpc.farnell.com/gentech-international/fs-02/flow-switch-300v-0-5amps/dp/SN35507?ost=sn35507

I put Tru Design hose barbs on each end and fitted the flow switch in line with the water flow. It’s been working very well for the last five years, and has saved my bacon on more than one occasion...

The flow switch provides a simple contact closure that you could use to drive a buzzer, but I made a standalone battery-powered electronic version to avoid running any new boat wiring. The rechargeable battery lasts about a year and the device plays a tune when the flow starts (to check the unit is working) and a different one when the flow stops.

That's the right principle but the one listed is too small. I'll have a look at Mr Farnell's other offers.

 

[Graham_Wright]

Got one (thanks Roger)
FS22A | Cynergy3 FS Series Flow Controller, 3.75 L/min, Relay Output, 240 V, 22 mm Pipe | RS

£35 and tomorrow delivery.

 

[Graham_Wright]

It's arrived (thanks RS) but it is gravity operated and detects upwards flow (although RS state it will work horizontally).
From sea valve to filter is upwards but filter to Jabsco is downwards. There are two inlets so I suppose I could double up.

 

[ridgy]

I was just about to get one of these:
SM010

 

[Graham_Wright]

I was just about to get one of these:
SM010

Bit too slow for Jabsco protection.

 

[jamie N]

This will indicate whether your hot bit is being cooled. You can easily set it to alarm if it isn't, and you can also monitor what the temperature is at the bit where you expect it to be 'warmer/cooler' than it is if everything's working OK.
The item's available at all the usual places, is reliable and costs about £3.50. I house mine in a wee tupperware pot, and it's about a fiver (including labour)!

 

[rickywright78]

Hi @jamie N

Can you share more of where / how you have fitted this. I’d be keen to give it a go so would love to know how you’ve went about it.

Thanks Ricky

 

[superheat6k]

Following the weed fouling and consequent seizure of the stbd engine on my last boat I have fitted both flow switches - Aqualarm and exhaust temperature probes - Silicon Marine.

Both systems are linked to the Stbd engine supply switch and both will operate very loud alarms, which can be silenced.

The set up cost me ~ £300. The wrecked engine directly cost ~ £8,000 to fix (which the Insurers paid for) and me since at least double that in lost no claims leading to higher premiums.

The bright outer LEDs are on when the engines are running and flow is present Red = Port (not danger) & Green = Stbd (not OK). The central amber LED is also a sound alarm, so flashes and buzzes if there is a problem, or when starting / stopping the engines, which pre-tests the switch functions each start up. One of the buttons on the Silicon panel cancels the buzzer, the other turns the whole set up on.

The flow switches mount in a 1 1/4" (32mm) hose, and use small bodied magnetic reed switches which are mounted outside the case of the switch so are never affected by the seawater passing through.

I would also say that in my industry the vast majority of water chillers are protected by paddle flow switches and not fancy electronic flow sensors.

I managed to break one of the glass phial reed switches due to rough handling when inserting into the hose, but Aqualarm kindly sent me two replacement switches FOC, so now I have a spare.

If this set up is of interest I have also attached the wiring diagram for the combined set up.