Priming Water Pump

[IamProStreet]

Went to de-winterize the trailer and the pump would not prime. It seems to do this on occasion. Was thinking about putting a tee in the feed line right next to the pump and having a line that was accessible without having to remove the wall. I would install a shutoff and a cap to insure no leaks. When need to prime the pump remove the cap and open the shutoff and pour some water into the tube and lift it up to get it to flow towards the pump. Any thoughts?

[Dwilcox]

These pumps should prime with no problem. If you are pulling up more than 10 feet, then maybe. All my pumps have pulled a prime at 4 feet of lift and 10 feet horizontally, no problem. If it won't pull a prime, then you may be sucking air somewhere, the most common cause. If you have a filter bowl just before the pump and you did not suck antifreeze through it, it may have a small crack in it.

[jimmarako]

Does your trailer have a shower miser or similar system? If so maybe its not fully closed.

Jim M.

[HangDiver]

Had this happen last year when I went to de-winterize. Realized I forgot to switch the valve from the antifreeze line to the FWT. Ooops.

[Bob K4TAX]

The diaphragm pumps don't require priming.

If the pre-filter bowl located in the line between the fresh water tank and the intake to the pump is cracked or loose it will suck air and not pump water.

If there is any leak on the intake side of the pump, it will suck air and not pump. Inspect all valves to assure they are in the correct position to pull water from the freshwater tank.

Bob

[IamProStreet]

I just use compressed air to winterize. The first time it happened we were on the road for the day. My water tank is at the rear of the trailer and the pump is about 20’ away. I pulled the bowl off the pump to add the water there and there was no cracks. Pretty sure the shower miser was fully turned off.

[Bob K4TAX]

Originally Posted by IamProStreet

I just use compressed air to winterize. The first time it happened we were on the road for the day. My water tank is at the rear of the trailer and the pump is about 20’ away. I pulled the bowl off the pump to add the water there and there was no cracks. Pretty sure the shower miser was fully turned off.

Yes, I too use compressed to blow out the lines and winterize. However, there is one caveat, the intake side of the pump and the filter is NOT in the pressurized line. Just remove the bowl, drain the water, and put it back securely in place. It will then be ready for the next camping season. And one does not need to remember to install it.

Bob

[NMWildcat]

When mine struggles to prime, I open a faucet for a few seconds then close. Let it run for a bit. Repeat. Sometimes it will take 10 minutes, but it always primes eventually w/o having to do anything else.
I take that back. Once the pump screen had to be cleaned out before it primed, years ago.

[NavyLCDR]

Originally Posted by IamProStreet

Went to de-winterize the trailer and the pump would not prime. It seems to do this on occasion. Was thinking about putting a tee in the feed line right next to the pump and having a line that was accessible without having to remove the wall. I would install a shutoff and a cap to insure no leaks. When need to prime the pump remove the cap and open the shutoff and pour some water into the tube and lift it up to get it to flow towards the pump. Any thoughts?

Why not just use the antifreeze suction hose? That being said, the diaphragm pumps used in RVs are self-priming. You either have an air leak, not enough water in the freshwater tank, or not enough patience.

[5picker]

Originally Posted by NMWildcat

When mine struggles to prime, I open a faucet for a few seconds then close. Let it run for a bit. Repeat. Sometimes it will take 10 minutes, but it always primes eventually w/o having to do anything else.
I take that back. Once the pump screen had to be cleaned out before it primed, years ago.

X2
I've had several times over the years where the pump wouldn't prime. A couple times when winterizing with antifreeze and once or twice otherwise.

There were no leaks and plenty of liquid to draw from. I think sometimes air pressure builds on the pressure side to where the suction side won't draw. Opening a faucet for a bit always has rectified the issue.

[IamProStreet]

Originally Posted by NavyLCDR

Why not just use the antifreeze suction hose? That being said, the diaphragm pumps used in RVs are self-priming. You either have an air leak, not enough water in the freshwater tank, or not enough patience.

Maybe I need to learn the proper procedure to prime the pump then. I let it run for about a minute or so then opened a faucet and air came out, shut the faucet then opened it and more air then no air the next time. Shut the pump off and waited 20 seconds or so and tried again. Probably ran the pump 4-5 minutes before taking the wall down to add water to the strainer bowl.

[Mr. Dan]

Originally Posted by IamProStreet

Maybe I need to learn the proper procedure to prime the pump then. I let it run for about a minute or so then opened a faucet and air came out, shut the faucet then opened it and more air then no air the next time. Shut the pump off and waited 20 seconds or so and tried again. Probably ran the pump 4-5 minutes before taking the wall down to add water to the strainer bowl.

The point is learning how to prime a diaphragm pump is not the issue. It shouldn’t have to be primed. The issue is figuring out why it loses its prime. Mine wouldn’t move water and there was something wrong with the check valve. I tried an experiment. I opened the valve to draw in antifreeze, turned on the pump, blew as hard as I could into the antifreeze take-up line, closed the antifreeze valve and the pump started moving water. The final fix for mine was installing a new pump head with its new check valve.

[IamProStreet]

Originally Posted by NavyLCDR

Why not just use the antifreeze suction hose? That being said, the diaphragm pumps used in RVs are self-priming. You either have an air leak, not enough water in the freshwater tank, or not enough patience.

Using winterize port may work exactly how I envisioned the tee. I will have to look into any suction leaks.

[IamProStreet]

Originally Posted by NavyLCDR

Why not just use the antifreeze suction hose? That being said, the diaphragm pumps used in RVs are self-priming. You either have an air leak, not enough water in the freshwater tank, or not enough patience.

Ran into pump loosing prime going from city water to dry camping. Set the Nautilus valves to sanitize and used a bottle of water to dump into the hose connection and the pump pulled it in and primed. Thanks for the suggestion!!!