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Old 03-31-2014, 06:19 PM   #14
LarryM
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City: League City, TX
Vessel Name: Pelago
Vessel Model: Wellcraft 3300 Coastal
Join Date: Aug 2011
Posts: 1,069
Quote:
Originally Posted by Ski in NC View Post
Not a simple question, really. Clamping on the mixer, once water flow stops the jacket becomes a void and heat transfer is poor. Attaching to the hose, heat transfer there is not very good either. I'm not sure which will pick up the heat first. Considering Borel's rep, I would defer to their instructions. They have probably tested in both places.

I used the mixer, partly because a SS clamp works well there, and also I use the mixer as the ground. Understood the limitations then, too.

I think either place works well enough.
I agree. Aqualarm makes a very similar alarm kit and state on their website "The Wet Exhaust detector has an aluminum band that adjusts from 2" to 8", making easy installation on the elbow or flexible hose." They supply 200F switches in their kits.

My Kohler diesel generator came from the factory with a temperature sensor on the mixing elbow that will shut it down if it gets too hot.

I don't think the location would matter much on a generator or small diesel, but I know for a fact that on high-horsepower Mercruisers, the hoses can overheat if there is reduced raw water flowing through the riser due to blockage or a failing pump. The flow is sufficient to cool the riser, but there is not enough water volume to mix with, and cool the exhaust gas at high power settings. The temperature downstream of the injection point can be significantly higher than the elbow itself. In these installations the mixing occurs in the hose, not the riser, so the band is best placed on the hose since it is the most susceptible to heat damage and failure.

Again, for our purposes, I would feel comfortable with either location.

Larry
M/V Boomarang
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