Pagetslady
Well-Known Member
Hi has any body fitted one of these Aqualarm raw water alarms if so does it reduce the flow, or if not this one what would you recomend.
Mike.
Mike.
Aqualarm raw water alarm
- Thread starter Pagetslady
- Start date
Flossdog
Well-Known Member
I have the Halyard sea strainer alarm on my boat which I guess is the same as the Aqualarm. Worked very well when first fitted but the control box has given up the ghost after 5 years. I have other overheat alarms so haven't bothered to replace it (at high cost!).
pampas
Well-Known Member
No to your question (Very slightly) Several years ago PBO showed how to make one' very reliable bits from Cpc and maplins I made one forgot the cost, compared to production units. Peanuts.
Mistroma
Well-Known Member
My previous boat's engine suffered a number of chokes on my first passage through the Forth & Clyde canal. I don't know what was shown in PBO but I fitted a DIY alarm about 12 years ago. It always alerted me when the filter was blocked or the pump lost suction for any reason.
I didn't attempt to monitor flow as temperature measurement was a much simpler option. The temperature of the raw water pump rose rapidly if the water flow rate dropped. I bought a digital thermometer with remote probe and an alarm. The probe was clipped to the pump body using a jubilee clip and the readout mounted outside the engine compartment.
I only spent £10-£20 and it worked extremely well. I think that the temperature usually sat under 10-12C but rose sharply to >30C within a minute of getting a choke. The impeller was never damaged as the pump still contained some water even when the strainer became blocked. Quite easy to get very early warning by setting the max. temp. alarm just above the normal running temperature.
I'd bet that it's still easy to buy a cheap digital thermometer with alarm and remote sensor. The only downside was that I still had to check the exhaist outlet after starting the engine (good practice anyway). The system only gives warning if a blockage happens after the engine block has warmed up. Not a very big problem.
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nimbusgb
Well-Known Member
I fitted one of the 22mm flow sensors in the intake side of my raw water system. The original piping is 1 inch. I ran a whole bunch of tests with endless hosepipes, buckets, a stopwatch and some drenchings. Made no discernable difference to flow.
pampas
Well-Known Member
Found the PBO article
View attachment 29054
This is the system I mentioned with all the bits required.
View attachment 29054
This is the system I mentioned with all the bits required.