I installed a new "shoot thru hull" transducer using silicone sealant like I have several times in the past. This meter is giving false readings or constantly displaying "1.5 feet". Before launching the boat, I had accidentally turned the power on to the meter for several minutes. I'm wondering if this has damaged the transducer, or maybe there is an air bubble between it and the bottom of the bilge.
Suggestions?
Doubt that the transducer would be faulty because you powered up the unit. If possible re-bed the transducer. I used bathroom caulking with good results, working the caulk between the transducer and hull to reduce any voids.
It's possible the transducer got hot . I've installed a number of them using the wax from a toilet seating kit.
Everyone of the chartplotters and depth meters I've installed had cautions about powering up the transducer out of the water .
I would try ,reseating it , check connections and try to program an offset to see if you can get a consistent reading .
The most common problem over the years has been a bad installation and air or a liquid throwing off the reading. A few had a problem because the hull at the site had something in its construction, thickness, material, gap that caused incorrect reading. If this is the same boat and site as before forget that problem.
I'm sure many people give a short test of power to the unit at the time of installation. I don't know about several minutes.
Once Debby has passed I'll remove the transducer and try re-installing it. This install was done on a 90+ degree evening with low light. Most likely it's bubbles in the silicone. The previous unit worked for years in this same spot until I accidentally ripped out the wire.