21EC fresh water tank will not fill

NW_Raven

New member
Joined
Jun 12, 2025
Messages
2
Fluid Motion Model
R-21 EC
Vessel Name
Little Brother
On my 2016 21EC, i am unable to fill the fresh water tank through the fill cap. The just sits there in the pipe and rejects any water injected.

I know the tank is empty because i filled it at the beginning of our trip, used a lot of water via the electric pump to the sink, and now that pump runs dry.

Ideas?
 
Plugged vent line?
 
Pull the cover on top of the tank off to expose the hoses if what’s visible above the cover to the vent and fill pipe looks OK. Only a few screws and the cover will lift out.
 
Took a look at some old photos of mine today. The fill line is 1-1/2" dia. or bigger so unlikely to be a vent issue. Opening the tap on the sink should also vent it and allow the fill hose to drain. Don't see how it wouldn't fill unless the fill hose is completely kinked or collapsed or somehow something has the hose plugged off. I pulled my tank a few years ago and added a drain line at the bottom to allow easier draining and flushing of plumbers glycol that I use to winterize the pump, tank and lines.
IMG_7081.JPGEMFJ8078.JPG
 
Thank you for the suggestions and ideas. (My reply has been delayed by my voyaging, which took me out of cell range for a while.)

I located the vent hose and detached it from the through-hull fitting. Since I was then able to put water into the tank, I figured the vent fitting was blocked in some way. Indeed, the mesh screen on the vent on the outside was crusted with salt and other particles. I washed it out as best I could, then re-attached the vent hose.

All works now.

In retrospect, the source of the problem seems obvious. However, I have never had this happen before on this or previous boats, so I was surprised more than anything.

Thanks again for the help, all.
 
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