I called Aqualarm. They recommend (although not in the package
literature) having the unit 12" from any elbows or fittings that could
upset the flow. My installation does not allow for this and I have a
180 degree hose bend just before the alarm. They don't know if this
is the cause or not but they would expect a pipe elbow to cause the
inconsidtent behavior I have observed.

They say the sensing is stable all the way to the low end of the
calibration. They can't explain why I sometimes can't get the alarm
to stop even by running RPM way up. That is an indication that it
should possibly be returned and checked but I don't want to take it
out this summer.

Their recommendation is to use it at lowest calibration which is 1 1/2
to 2 gpm. This is what I have been doing the past few days. It won't
give me early warning that the strainer is plugging or the water pump
failing but will alert me to the seacock being closed or a bag getting
over the intake. I think that is worth keeping it in the boat
although I think I would go with a proper temperature gauge if I was
doing it over.

--

Roger Long



"Roger Long" wrote in message
.. .
I'm finding the Aqualarm raw water flow alarm to be a much better
idea in theory than practice. I'm going to call them soon and would
be like to hear any other experiences.

Basically, the calibration seems to drift constantly. I resigned
myself to having to recalibrate it every time I start the engine
which isn't a big deal while I'm waiting for the engine to warm up.
I just set 1000 RPM and push the collar until it just shuts off.
That leaves it set to come on at the water flow corresponding to
about 800 RPM which makes it a nice warning that I'm letting the
engine get slow enough that it might stall during docking.

However, I restart the engine when the wind dies after sailing and
the alarm is going. About half the time I can get it to shut up by
running the RPM briefly up into the cruise range. The rest of the
time, it won't stop beeping until I go down and shove the adjusting
collar to a lower setting. I would think this is my raw water
system draining down and the pump losing its prime except that
plenty of water is coming out the exhaust.

I have a small engine and am using it near the bottom of the unit's
calibration range where it probably isn't as stable. It must work
better with engines 50 hp and up than with my 20 hp Yanmar or it
would have been off the market long ago.

--

Roger Long