Priming AC water pump

[km1125]

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Also, can anyone confirm the AC discharge is the far left discharge with the stain in this photo?

A lot of times it's the condensate drain that gets the stains, because there's some rusting going on in the bottom of the pan below the A/C unit. You don't want to squirt water back into that if it is indeed the condensate drain. Sometimes the condensate drains into the shower sump, which then gets pumped overboard and causes a similar stain. You also don't want to squirt water back into that drain either. You can run the shower and see where that water gets pumped out to determine which thru-hull serves which purpose.

[Rocketman]

I personally loosen the output hose from the pump to let the air out when the pump is running. As soon as you get water flow tighten back up. Sometimes you can run the boat at about 15 mph or more and the water pressure pushing water up will prime it as well.

[tomschauer]

I installed a tee and a valve in my discharge line. Crack the valve until you get water and then close it. Good to go. Also helps to winterize.

[km1125]

QR_BBPOST I installed a tee and a valve in my discharge line. Crack the valve until you get water and then close it. Good to go. Also helps to winterize.

If this happened frequently you could put that "T" in and a 12V water valve with the output plumbed over the side somewhere. Add a push-button switch to activate the water valve to 'purge' air. The overboard line is really just in case there are any leaks when the valve isn't activated.

[Midnightsun]

Still am pretty sure if you inspect the lines and look for a rise in the hose between the filter and pump where air could get trapped you will correct the priming issue. Bottom line is if water can naturally get to the pump then you do not need to prime. Think of the water intake and the line from there as just an open line as this is essentially what it is. Water will flow naturally from the inlet until it reaches the point in the system where the line is higher than the water level. As long as the pump is flooded then it will operate normally.

If you simply cannot figure this out or do not want to, a simple t connection from your potable water line with an in-line valve will do the trick. Just open the valve and a rush of water will be supplied. Close the valve and you are good to go. Only thing to remember is you do need to have your water pump on when doing this.

[tomschauer]

For me, it only happens once per year. The pump will not push the air out of the system until it develops full flow. It takes a few seconds with the valve open to purge the air from the strainer to the pump outlet.

[kclife]

OK so we unscrewed the pump from the mount and lowered it below the filter and it was able to fill up the water pump and re-prime the system. Thanks for everyone’s help-all systems go for now! We plan on remounting the water pump so it is lower than the filter to avoid losing prime in the future when we clean the filter.