Hi, I am new to sailboats. My family and I just got our new (old) sailboat and we have been working on it.
We have an oldie but goodie.
Our marine diesel heater pump sounds like it runs continuously. Is that normal? Or should it turn on and shut off?
The heater itself works great. I'm just concerned about the pump

Thank you in advance!

Get to know your systems. Most older but good heater systems use a pulse pump .Pump can go direct to furnace carburetor or to a day tank for a gravity feed. Day tanks need to overfill back to source and be monitored while filling. (needs vent too) I found the twist knob timer switch from older small washing machines allowed for 1/2AI..Pump pulse fast buzz. A day tank with a deck fill allows switching to stove oil or diesel as seasons change.Pumps direct to carb depend on the float and needle to control the fuel flow .If that fails or flameout or heavy sooting fuel will eventually fill the bilge. Slow click speed dependent on carb setting. Pump switch should be safe distance from heater .Allways carried a spare pump but never used it .Most problems were results of too low heat settings (sooting)

 

Cape Len nailed this. Ours cycles with the furnace duty but runs continuously. It would helpful to know what type of diesel heater you have.