Dometic/March raw water pumps for HVAC

[ahill]

Had my pump wake me up in the middle of the night making one hell of a noise!
After several weeks of working at the problem (boat is 150 miles away), I discovered that these pumps work thru a magnetic field.
There is no connection between the pump and impeller housing. The pump has a cylindrical magnet secured to the motorshaft by a set screw. The impeller is in a nylon housing that fits into the cylinder causing a large metal base on the impeller shaft to spin!
My set screw had backed out. Put some locktite on it, tightened it and problem solved after 3 motel nights sorting it out. BTW the Dometic pump is made by March. Lewis Marine Supply in FL was $100 cheaper than BOW for a replacement pump and also has the impeller/magnet housing for $90.

 

[BobP]

I understand the magnetic coupling isolates the 120V motor from possible water penetration versus conmventional seals, not so safe if it occurs. As well as perhaps a softer (quieter) start.

March makes good pumps, and Dometic has been buying up everything including Cruise Air and Marine Air A/Cs, and then locking up the product prices from fair market forces in finding sales / doscounts and the like, which I don't like.

My new AC had to be Mermaid Marine, in response!
And the March pump I specified had a second label on the box as I recall; "Dometic".

 

[ahill]

My Dometic labeled pump, when stripped of it's appendages, revealed March stamped on the end plate!